When is a blood test for immunity tension prescribed? Protective levels of anti-polio antibodies How to determine if a vaccine is needed or not

Poliomyelitis is an acute viral disease that can lead to death or severe damage to the central nervous system. Mass vaccination has made significant progress in the fight against this disease. However, it still remains endemic to a number of countries in Africa and Asia. Outbreaks of the disease have been recorded in recent years in the states bordering Russia.

immunity to polio

Having immunity to polio reduces the chance of getting sick to a minimum. Vaccination and allow to form such resistance of the body to infection. However, even if all the measures have been taken, over time, the body's immune defenses may weaken. Permanent immunity is developed in persons who have had a disease or are vaccinated with a live vaccine.

To find out if a person has antibodies to the polio virus, a serological blood test is performed. This study allows you to determine the risk of infection when faced with a virus. Usually an antibody test before traveling to regions where cases of polio have been recorded.

Where can I get an antibody test

Testing for antibodies to the polio virus is performed in public and commercial laboratories. The study is not very popular, therefore, it is not carried out in all medical centers. To find out exactly where in your city you can do the analysis, consult with your local doctor or a specialist in the sanitary and epidemiological station.

In public institutions, the study is performed if there are indications. A referral for a free analysis can be given by an infectious disease specialist at a district clinic. In paid centers, the cost of determining antibodies to polio varies from 1,000 to 3,000 rubles.

How to test for polio antibodies

For the qualitative and quantitative determination of antibodies to the poliomyelitis virus, an enzyme immunoassay method is used. Antibodies are detected in serum or plasma. The result fluctuates ranging from 0 to 150 U/ml. If the titer is above 12 U / ml, we can talk about the presence of immunity to infection.

It is better to come to the study in the morning before the first meal. In a patient from a vein. It is believed that 0.5-1 ml of blood is sufficient for diagnosis. Paid analysis is performed within 1-2 working days, free - within two weeks.

The factors influencing the intensity of the immune response in humans to the introduction of vaccines are indicated. Data are given on significant fluctuations in the level of antibodies in those vaccinated with the same vaccine: from very high antibody titers to their complete absence. The necessity of correcting the development of immunity during vaccination is substantiated, methods and means of such correction are described. It is proposed to use the principles of individualization of vaccination, first of all, in high-risk groups.

The most effective method of combating infectious diseases is vaccination of the population. Each country develops its own vaccination calendar, taking into account the specifics of the epidemic situation, the availability of registered vaccines, financial capabilities and other factors. In all countries and large regions, a differential approach is used to vaccinate certain groups of individuals and individual contingents, taking into account:

  • demographic factors;
  • natural, climatic conditions;
  • epidemiological situation;
  • social factors.

There are groups of people at increased risk, the vaccination of which has its own characteristics:

  • risk groups associated with professional characteristics (medical workers, catering staff, etc.);
  • elderly and aged persons;
  • pregnant women;
  • newborns;
  • traveling abroad to endemic regions;
  • refugees.

High-risk groups of children include:

  • premature and weakened children;
  • children with immunodeficiencies (congenital immunodeficiency, HIV infection, radiation, drug immunosuppression, etc.);
  • patients with acute and chronic diseases (frequent SARS, diseases of the cardiovascular system, diseases of the blood, endocrine and nervous systems, etc.).

For differential vaccination apply:

  • vaccines of the same name with varying degrees of reactogenicity and immunogenicity (live, inactivated, split, subunit vaccines);
  • vaccines with a reduced content of toxoid (ADS-M, AD-M vaccines for routine age-related immunization) or with a reduced number of bacterial cells (BCG-M vaccine for vaccinating premature and debilitated children);
  • routine and accelerated immunization schedules for certain infections, such as hepatitis B;
  • different doses of vaccines for adults and children when immunized with the same vaccine (vaccines against hepatitis A and B, influenza, tick-borne encephalitis, etc.).

Unfortunately, this is where selective vaccination methods end. Vaccination of people is limited by the requirements of the vaccination calendar, various provisions and instructions, deviation from which entails legal liability in the event of post-vaccination complications. The vaccination calendar with averaged doses of vaccines and strict vaccination schedules equalizes the conditions for immunization of most citizens and is designed for an average person in terms of immunological activity.

In practice, individual vaccination schemes are not used, not to mention the use of any individual vaccines. In the recent past, attempts have been made to use autovaccines for the treatment of chronic infectious diseases (4, 21). Such vaccines were prepared from the microbial flora isolated from a particular patient and used to treat the same patient. Despite a good therapeutic effect, such vaccines are not produced due to great technological difficulties and the unprofitability of independent quality control.

When discussing the issues of immunological individualization of vaccination and developing the principles for its implementation, it is important to agree on the very concept of immunological individualization of vaccination. The following definition can be given: immunological individualization of vaccination is the correction of the immune response to vaccines using various means and methods of vaccination in order to create sufficient immunity in each person vaccinated (14). For such a correction, you can use different doses and vaccination schedules, as well as additional means of immunomodulating the immune response.

The susceptibility of people to infectious diseases is associated with the presence on their cells of special receptors for the pathogens that cause these infections. Mice are not susceptible to infection with the polio virus. At the same time, transgenic TgPVR mice susceptible to poliomyelitis have been created by introducing into their genome a gene encoding a cell receptor for the poliomyelitis virus (34, 38). Solving the problems of individual vaccination would be greatly accelerated if we knew the degree of sensitivity of each person to individual infections. There are no reliable methods for determining such sensitivity yet.

Immunological anti-infective resistance is under polygenic control; it consists of two systems of resistance: non-specific and specific. The first system includes nonspecific immunity factors and is controlled predominantly by genes not associated with the major histocompatibility complex (MHC). The second system ensures the development of acquired immunity associated with the formation of antibodies and effectors of cellular immunity. This system has its own genetic control, which depends on the MHC genes and their products (12, 13, 15).

There is a close relationship between a person's sensitivity to certain types of infections, the intensity of emerging immunity and the presence or absence of certain histocompatibility antigens, which are controlled by genes located in the A, B and C class I loci and the DR, DQ and DP class II loci of the HLA system ( Table 1).

Table 1. Immunity, infections and the HLA system

infections Association of HLA gene products with immunity and infections Literature
Immunity infections
Leprosy A1O, A1, B8, B14, B17, B7, BW40, B40, DR2, DR1, DR8 A2, AW19, DR4, DRW6 1, 37, 44,45
Tuberculosis BW40, BW21, BW22, BW44, B12, DRW6 B5, B14, B27, B8, B15, A28, BW35, BW49, B27, B12, CW5, DR2 1, 25, 26, 32, 41
salmonnelosis
A2 1
S. aureus infections DR1, DR2, BW35 DR3 1
Malaria BW35, A2-BW17 B53, DRB1 1,27
Measles
A10, A28, B15, B21 2
HIV infection B27 B35, A1-B8-DR3 29, 30, 31, 33, 35, 40
Hepatitis B DRB1
28, 42
Hepatitis C DR5
39, 43, 46

Insufficiently intense immunity to measles is associated with the presence of histocompatibility antigens AYu, A28, B15, B21, and the levels of the relative risk of the disease, respectively, for these markers are 3.2; 2.3; 3.4 and 4.0 (2). The presence of individual histocompatibility markers adversely affects the course of this infection. Individuals with A2, B7, B13, Bw 35, DR 2 antigens, and especially combinations of them, have a more severe course of measles compared to people with Al, B8, Cwl, DR3 antigens, and combinations thereof (24).

The mechanisms of action of MHC gene products, the presence of which increases the risk of disease, remain unknown. According to the most common hypothesis of mimicry, the structure of some microbial antigens is similar to the structure of such products, which allows viruses and bacteria to avoid the action of a protective reaction from the immune system.

The existence of a reverse association, when a high level of individual MHC antigens is combined with a high degree of resistance to an infectious agent, is explained by the fact that these antigens are products of lr genes (immune response genes), which determine the strength of the immune response to specific antigens. It is known that different people respond differently to the same vaccine. There are groups of individuals with strong and weak immune responses to each vaccine. The bulk of people occupy the middle position (3, 5, 6, 13, 17).

The strength of the immune response to a particular antigen depends on many factors: the composition of the vaccine and its antigens, the genotype of the organism, its phenotype, age, demographic, occupational factors, environmental factors, seasonal rhythms, the state of physiological systems, and even blood types. Individuals with blood type IV are more likely to experience T-system deficiency, which increases the risk of infections (8). Individuals with blood groups I and III have lower titers of anti-diphtheria and anti-tetanus antibodies (20).

Any antigen (bacteria, virus, large molecular antigen) after phagocytosis (pinocytosis) undergoes intracellular cleavage by phagolysosome enzymes. The resulting peptides interact with the products of the MHC genes formed in the cell and are presented in this form to lymphocytes. The lack of MHC products capable of binding to exoantigens leads to a decrease in the level of the immune response. Genetic control of the immune response and its restriction by MHC antigens is carried out at different levels of the immune system: at the level of auxiliary cells, helpers, effector cells, memory cells.

For many infections, a protective antibody titer has been determined, which provides resistance to infection in vaccinated people (Table 2). Protective titer, of course, is a relative concept. Sub-protective titers can play a significant role in anti-infective resistance, and high antibody titers are not an absolute guarantee of protection.

Table 2. Protective and maximum antibody titers in vaccinated

infections Antibody titers after vaccination Methods for the detection of antibodies
Protective titer Maximum credits
Diphtheria 1:40 ≥1:640 RPGA
Tetanus 1:20 ≥1:320 RPGA
Whooping cough 1:160 ≥1:2560 RA
Measles 1:10 ≥1:80 RNGA
1:4 ≥1:64 RTGA
Mumps 1:10 ≥1:80 RTGA
Hepatitis B 0.01 IU/ml ≥10 IU/ml
ELISA
Tick-borne encephalitis 1:20 ≥1:60 RTGA

For some types of vaccines, it is not possible to establish a protective titer. The level of circulating antibodies may not reflect the degree of protection of the body against infections, since in addition to humoral immunity, cellular immunity is involved in any anti-infective resistance. For most infections, protection against which is due to cellular factors (tuberculosis, tularemia, brucellosis, etc.), protective titers of cellular reactions after vaccination have not been established.

All measures for the specific prevention of controlled infections are aimed at creating herd immunity. To assess the effectiveness of such activities and the state of herd immunity, serological monitoring is carried out. The results of such monitoring indicate that even in the presence of herd immunity, there are always groups of individuals who do not have a protective level of antibodies (Table 3).

Table 3. Assessment of herd immunity to vaccine-preventable infections *

infections Test systems Contingent Presence of antibodies Number of vaccinated with antibody levels below protective
diphtheria, tetanus RPGA Children Antibody titers less than 1:20 No more than 10%
RPGA adults Seronegative No more than 20%
Measles ELISA Children Seronegative No more than 7%
Rubella ELISA Children Seronegative No more than 4%
Mumps ELISA Seronegative No more than 15%
ELISA Children vaccinated once Seronegative No more than 10%
Polio RN Children Seronegative Not more than 20% for each strain

* “Organization and conduct of serological monitoring of the state of herd immunity against controlled infections (diphtheria, tetanus, measles, rubella, mumps, poliomyelitis). MU 3.1.1760 - 03.

The immune response to vaccination varies from person to person. Individuals who respond poorly to one vaccine may respond well to another vaccine. Of paramount importance in this phenomenon are the genetic characteristics of the organism, which have been well studied in experiments on inbred mice using synthetic peptides containing 8-12 amino acids as antigens. Any large molecular antigen used to prepare a vaccine contains several such determinant groups, each of which causes its own immune response. The immunological response to a vaccine is essentially the sum of the responses to the peptides, so the differences between strong and weak vaccine responsive groups are smoothed out. An even more complex mosaic of immune responses occurs with the introduction of complex vaccines aimed at preventing several infections. In this case, the majority of those vaccinated respond well simultaneously to several antigens of complex combined vaccines, however, it is always possible to identify groups of people who respond poorly to 1-2 or several types of vaccines (5).

Characterization of the immune response to the introduction of vaccines.

Weak answer:

  • characterized by a low concentration of antibodies,
  • does not provide specific protection against infections,
  • is the cause of the development of bacteriocarrier and virus carrier.

Very strong answer:

  • provides specific protection against infections,
  • inhibits the formation of new antibodies,
  • prevents the engraftment of the virus of live vaccines,
  • promotes the formation of immune complexes,
  • increases the side effects of vaccines,
  • increases economic costs.

The basis for the development of the problem of correcting the development of immunity during vaccination are: the heterogeneity of the immune response to vaccines, the need for additional protection of individuals who respond poorly to vaccines, and the inappropriateness of excessive immunization.

The absence of an immune response and a weak immune response during vaccination is observed in 5-15% of apparently healthy individuals. Children who respond poorly to vaccines are more common among children with clinical signs of immunological disorders (16). More than 10% of individuals respond poorly to certain types of vaccines: 11.7% to live measles vaccine (2), 13.5% to recombinant hepatitis B vaccine (36), etc. In addition, a large percentage of apparently healthy people respond poorly to weakly immunogenic vaccines.

The second side of the problem is over-immunization. Due to the constant circulation of pathogens of some infections, people are naturally immunized without vaccination. Some of them have a high initial antibody titer and do not even need primary vaccination. Other individuals produce very high antibody titers after primary vaccination and do not need to be revaccinated.

Among the vaccinated, it is always possible to distinguish a group of people with high and very high levels of antibodies. This group makes up 10-15% of those vaccinated. When vaccinated against hepatitis B, antibody titers above 10 IU/ml are observed in 18.9% of people with a protective titer of 0.01 IU/ml (36).

Hyperimmunization occurs more frequently with boosters, which are required by the label for most commercial vaccines. With intensive formation of antibodies, revaccination is unnecessary and undesirable. Individuals with high levels of pre-antibodies respond poorly to revaccination (7,9). For example, among individuals who had high titers of anti-diphtheria antibodies before vaccination, 12.9% of people did not change the concentration of these antibodies after the administration of ADS-M toxoid, and in 5.6% of individuals, antibody titers became lower than the initial level (9). Thus, 18.5% of people did not need revaccination against diphtheria, and some of them revaccination was contraindicated. From the point of view of expediency, medical ethics and economy, excessive immunization is unjustified.

Ideally, it is desirable to have an idea of ​​the strength of a person's immunity to a particular infection even before vaccination. There are methods for mathematical prediction of the immunological efficacy of vaccination (revaccination) based on the immunological monitoring of large groups of people. However, the problem of predicting the development of immunity to a vaccine in individual people is practically not developed. The difficulties of such forecasting lie in the fact that the immune response to a vaccine is always specific, the body reacts differently to different vaccines.

There are several ways to determine indicators by which one could indirectly judge the immunological potencies of the body (18, 19). These indicators can be specific, associated with a specific antigen (vaccine), or non-specific, characterizing the state of non-specific immunity factors. It should also take into account the vaccination history, gender, age, profession, the presence of pathology in the vaccinated and other non-specific factors, which, of course, are not absolute criteria for assessing the specific protection of people from specific infections (3). Data from immunological studies should be included in the medical records of all vaccinated. These data will be the basis for making a decision on the need to use means of correcting immunity.

Immunity assessment can be performed before and after primary immunization or at any stage of the vaccination cycle. This allows you to determine the need for further immunization, cancellation of vaccination, or, conversely, the adoption of measures to enhance the immune response of the vaccinated. Correction of the level of immunity by antibody titers in high-risk individuals is available and real. Standard highly sensitive test systems that have passed all stages of registration should be used. It is expedient to develop test systems for the simultaneous determination of the level of antibodies to the antigens of many vaccines, for example, vaccination schedule vaccines.

To assess immunity, two parameters can be taken: the protective titer and the upper level of antibodies, which should not be exceeded by repeated vaccination. Establishing the upper level of antibodies is much more difficult than the protective titer. As such a level, upper titer values, slightly below the maximum values ​​determined in clinical trials of each vaccine, can be used.

In the practice of vaccination, it is impossible to arbitrarily change vaccination schedules, however, even now, in the instructions for the use of vaccines for the prevention of certain infections (rabies, tularemia, Q fever, etc.), it is prescribed to administer additional doses of drugs to recipients, provided that the level of antibodies after the previous vaccination did not reach protective titer.

Advantages of individualization of vaccination:

  • in a shorter period of time, herd immunity is formed,
  • the circulation of pathogens is reduced,
  • the number of cases of bacteriocarrier and virus carrier is reduced,
  • a large contingent of the population will be protected, another contingent will be spared from hyperimmunization,
  • the frequency of adverse reactions during vaccination decreases,
  • many ethical problems of vaccine prophylaxis will be solved.

Immunological personalization of vaccination can be carried out by selecting a vaccine among similar vaccines, choosing doses, vaccine administration schemes, using adjuvants and other immunomodulating agents. Naturally, each vaccine has its own characteristics, and each vaccine preparation requires its own tactics of immunological correction. At the same time, general methods and means of correcting the immune response to various types of vaccines can be recommended.

In healthy individuals with a level of immunity below protective:

  • increasing the dose of the vaccine
  • use of more immunogenic unidirectional vaccines,
  • the use of additional means to increase the immunogenicity of vaccines (adjuvants, cytokines, etc.),
  • change in the vaccination schedule (additional vaccination, etc.).

In healthy individuals with overproduction of antibodies:

  • reducing the dose of vaccines
  • reduction of the primary vaccination schedule,
  • refusal of revaccination. In persons with pathology:
  • the use of vaccines with a reduced antigenic load,
  • the use of vaccines administered by gentle methods,
  • change in the vaccination schedule.

Studies show that in most individuals with a weak immune response, protective antibody titers can be obtained with the help of additional stimulation agents. The number of refractory people who do not respond to a particular vaccine, which is associated with the genetic characteristics of these individuals, does not exceed tenths of a percent.

In medical practice, there are still no conditions for determining the level of antibodies in all vaccinated, although serological monitoring is widely used to assess herd immunity, and serological screening is used to select contingents of people when testing new vaccines, for example, vaccines against diphtheria (11), hepatitis B (36 ) and other infections.

The principles of immunological correction of vaccination should be extended primarily to risk groups, for example, when vaccinating people with various types of pathology: immunodeficiencies (23), allergies (10), malignant neoplasms (22), HIV infection, radiation, drug immunosuppression, etc.

Not all the provisions expressed in the article are indisputable, some of them require additional research. It is important that the problems of immunological individualization of vaccination be discussed in the scientific community and developed as soon as possible. Naturally, all changes in doses and schemes for the administration of specific vaccines, the use of means and methods for individualizing vaccination must be considered and approved in the prescribed manner.

It can, of course, be objected that the immunological correction of vaccination is not so necessary, since the correct implementation of vaccination already now makes it possible to prevent the epidemic process in relation to any controllable infection. At the same time, it should be taken into account that due to the introduction of immunological correction methods, most of the low-reacting individuals will be protected from infections, and the other part of the population will be spared from excessive hyperimmunization. Both of these groups of people make up about 20-30% of all vaccinated people. There is every reason to believe that individual adjustment of vaccination will significantly reduce the incidence of adverse reactions and complications after the introduction of vaccines. Selective immunization can solve many of the burning ethical problems of mass vaccination.

The costs of introducing immunological correction methods will be largely compensated by the cancellation of vaccination of 10-15% of hyperreactive people, and, as a result, large savings in vaccines. There will be a partial redistribution of the volume of vaccines from those who are not shown them to those who need them for additional stimulation of immunity.

In conclusion, it should be noted that the problem of immunological individualization concerns not only vaccines, but also other immunobiological drugs, primarily various immunomodulators, which are widely used for the prevention and treatment of many types of human pathology.

MU 3.1.2943-11

METHODOLOGICAL INSTRUCTIONS

3.1. PREVENTION OF INFECTIOUS DISEASES

Organization and conduct of serological monitoring of the state of collective immunity to infections controlled by means of specific prevention (diphtheria, tetanus, whooping cough, measles, rubella, mumps, poliomyelitis, hepatitis B)

1. DEVELOPED by the Federal Service for Supervision of Consumer Rights Protection and Population Welfare (E.B. Ezhlova, A.A. Melnikova, G.F. Lazikova, N.A. Koshkina); FBUZ "Federal Center for Hygiene and Epidemiology" of Rospotrebnadzor (N.Ya. Zhilina, O.P. Chernyavskaya); G.N. Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology of Rospotrebnadzor (N.M. Maksimova, S.S. Markina, T.N. Yakimova, N.T. Tikhonova, A.G. Gerasimova, O.V. Tsvirkun, N.V. Turaeva, N.S. Kushch); FGUN "Central Research Institute of Epidemiology" of Rospotrebnadzor (V.P. Chulanov, N.N. Pimenov, T.S. Selezneva, A.I. Zargaryants, I.V. Mikheeva); State Institution "Institute of Poliomyelitis and Viral Encephalitis named after M.P. Chumakov" of the Russian Academy of Medical Sciences (V.B. Seybil, O.E. Ivanova), State Institution "Moscow Research Institute of Vaccines and Serums named after I.I. Mechnikov of the Russian Academy of Medical Sciences (N V. Yuminova, R. G. Desyatskova); Omsk State Medical Academy (V. V. Dalmatov); Office of Rospotrebnadzor for the Novosibirsk Region (N.I. Shulgina); Office of Rospotrebnadzor for Moscow (I.N. Lytkina, V.S. Petina, N.I. Shulakova).

2. DEVELOPED instead of guidelines MU 3.1.1760-03 "Organization and conduct of serological monitoring of the state of herd immunity against controlled infections (diphtheria, tetanus, measles, rubella, mumps, poliomyelitis)".

3. APPROVED on July 15, 2011 and put into effect by the Chief State Sanitary Doctor of the Russian Federation G.G. Onishchenko.

1 area of ​​use

1 area of ​​use

1.1. The guidelines set out the basic principles for organizing and implementing serological monitoring of the state of herd immunity to infections controlled by means of specific prevention (diphtheria, tetanus, whooping cough, measles, rubella, mumps, poliomyelitis, hepatitis B).

1.2. These guidelines are intended for specialists of the bodies exercising state sanitary and epidemiological supervision, and specialists of medical and preventive organizations.

2. General provisions

2.1. Serological monitoring allows for a continuous process of objective assessment of the state of specific post-vaccination immunity to infectious agents controlled by means of specific prevention in "indicator" population groups and risk groups and is an indispensable element of epidemiological surveillance for diphtheria, tetanus, whooping cough, measles, rubella, mumps , poliomyelitis and hepatitis B, since epidemiological well-being in relation to these infections is determined by the state of post-vaccination immunity.

2.2. The purpose of serological monitoring is to assess the level of actual protection against infections of individuals, groups and the population as a whole, as well as to assess the quality of vaccination work in a particular area and in a particular healthcare organization.

2.3. Serological monitoring includes:

selection of "indicator" groups of the population, the state of specific immunity of which makes it possible to extrapolate the results obtained to the population of the surveyed territory as a whole;

organizing and conducting serological studies of blood sera of vaccinated people (in "indicator" population groups);

assessment of the effectiveness of the immunization.

The procedure for collecting, transporting and storing blood sera for research is carried out in accordance with Appendix 1.

2.4. "Indicator" populations include individuals with a documented vaccination history. At the same time, the period from the last vaccination to the examination for the presence of diphtheria and tetanus antibodies, pertussis agglutinins, antibodies to measles, rubella, mumps, poliomyelitis, hepatitis B viruses should be at least 3 months.

The introduction of "indicator" groups makes it possible to unify the forms and methods of analysis of inoculation work.

2.5. The organization and conduct of serological monitoring of the state of collective immunity of the population is carried out by healthcare organizations and bodies exercising state sanitary and epidemiological surveillance.

2.6. Conducting serological monitoring of the state of herd immunity is formalized by a resolution of the Chief State Sanitary Doctor for the constituent entity of the Russian Federation, in which, in agreement with the health authorities, the territories, time (schedule), contingents and number of population groups to be examined are determined, microbiological laboratories for research are determined, and as well as the persons responsible for the organization and conduct of this work.

In development of the decision of the Chief State Sanitary Doctor for the constituent entity of the Russian Federation, an order is issued by the health management authority of the constituent entity of the Russian Federation.

Serological monitoring is annually included in the work plans of the territorial bodies of Rospotrebnadzor and healthcare organizations.

3. Materials and methods

3.1. The material for the study is blood serum, the detected antibodies in which are a source of information about the level of immunity to infectious agents controlled by means of specific prophylaxis.

3.2. The methods used for the study of sera should be harmless, specific, sensitive, standard and available for mass examinations.

3.3. To conduct serological studies of blood sera in the Russian Federation, the following are used:

passive hemagglutination test (RPHA) - to detect antibodies to the measles virus, diphtheria and tetanus toxoids;

agglutination test (RA) - to detect pertussis microbe agglutinins;

enzyme immunoassay (ELISA) - to detect antibodies to measles, rubella, mumps, hepatitis B, and whooping cough;

reaction to neutralize the cytopathic effect of the virus in tissue cell culture (macro- and micromethod) - to detect antibodies to poliomyelitis viruses.

3.4. For serological studies, diagnostic kits and test systems registered in the Russian Federation should be used.

4. Methodological approaches to the selection of population groups

4.1. When forming "indicator" populations subject to serosurvey, the following principles should be followed.

4.1.1. The unity of the place of vaccination (health organization, preschool institution, school and other organizations where vaccinations were carried out).

This principle of group formation makes it possible to identify organizations with a low quality of vaccination work, and during a subsequent thorough investigation, to determine its specific shortcomings (violation of the rules for storage, transportation of vaccines, falsification of vaccinations, their inconsistency with the terms and schemes of the existing preventive vaccination calendar, technical errors, etc.).

4.1.2. Unity of vaccination history.

The surveyed population group should be homogeneous, which requires the selection of individuals with the same number of vaccinations and the period from the moment of the last vaccination.

4.1.3. The similarity of the epidemiological situation in which the surveyed groups are formed.

To implement the requirements of this principle, the formation of groups is carried out from groups in which cases of diphtheria, whooping cough, measles, rubella, mumps, and hepatitis B have not been registered for one year or more.

4.2. The selection of contingents for the survey begins with the definition of territories.

The boundaries of the territory are determined by the service sector of a healthcare organization. This may be a separate organized team of children and adults, a medical station, a settlement assigned to a feldsher-obstetric station, a service area of ​​one polyclinic.

4.3. Serological monitoring should be carried out primarily in large administrative territories of the constituent entities of the Russian Federation (in cities, regional centers) - annually. Each year, different districts and polyclinics of the city (district center) should be included in the survey. The frequency of their examination should be 6-7 years (according to the schedule).

4.4. To form an "indicator" group, 4 teams of subjects of the same age should be selected (2 teams from 2 healthcare organizations), at least 25 people in each team, that is, in each "indicator" group there should be at least 100 people.

4.5. Before conducting a serological examination of persons selected for the "indicator" group (children and adults), medical workers should conduct explanatory work, including with the parents of the examined children, about the purpose of checking their post-vaccination immunity to infections controlled by means of specific prophylaxis.

4.6. Adult blood sera can be collected from blood transfusion stations for testing.

The procedure for collecting, transporting and storing blood sera is defined in Appendix 1.

5. "Indicator" populations subject to serological screening for the presence of specific antibodies

5.1. Serological monitoring of the state of herd immunity provides for a multi-purpose serological survey in each territory of "indicator" population groups.

Multipurpose serological studies involve the determination in one sample of blood serum the maximum spectrum of antibodies to the pathogens of the studied infections.

5.2. The "indicator" groups do not include:

who had been ill with whooping cough, diphtheria, tetanus, measles, rubella, mumps, poliomyelitis and acute hepatitis B, as well as patients with chronic hepatitis B and carriers of the hepatitis B virus;

children who do not have information about vaccinations;

not vaccinated against these infections;

who have had any disease 1-1.5 months before the examination, since certain diseases can lead to a temporary decrease in the titer of specific antibodies.

5.3. The state of collective immunity to diphtheria, tetanus, mumps, poliomyelitis, hepatitis B in adults is determined without taking into account vaccination data. The state of immunity to measles and rubella - excluding vaccination data, is determined in adults only in the age group of 40 years and older.

5.4. Diphtheria and tetanus.

Based on the results of a serological examination of children aged 3-4 years, the formation of basic immunity is assessed, and at the age of 16-17 years, the quality of vaccinations carried out at school and secondary educational institutions is assessed.

The results of serological examinations of adults aged 18 years and older (by age groups) without taking into account their vaccination allow us to assess the actual level of protection against diphtheria and tetanus in adults in each age group and identify risk groups for morbidity and severity of the disease.

5.5. Whooping cough.

Based on the results of a serological examination of children aged 3-4 years, an assessment is made of the formation of basic immunity.

5.6. Measles, mumps, rubella.

Based on the results of a serological examination of children aged 3-4 years and 9-10 years, an assessment is made of the level of anti-measles, anti-mumps and anti-rubella immunity after vaccination and revaccination.

Serological examination of children aged 16-17 years, allows you to evaluate the effectiveness of revaccination in the long term, as well as the level of the immune layer to these infections in the newly emerging teams of secondary and higher educational institutions.

The results of a survey of adults aged 25-29 and 30-35 years old, vaccinated against measles, rubella and mumps, characterize the state of specific immunity among the young adult population, including rubella - women of childbearing age.

Based on the results of a survey of adults aged 40 years and older (donors, excluding vaccination history), an assessment is made of the actual protection of the adult population from measles, rubella and mumps.

5.7. Polio.

Based on the results of a serological examination of children aged 1-2 years, 3-4 years and 16-17 years, an assessment is made of the level of immunity to poliomyelitis in the shortest possible time after vaccination and revaccination with polio vaccine, in adults - the actual state of immunity to polio in the age groups of 20- 29 years old, 30 years old and over.

5.8. Hepatitis B.

Based on the results of a serological examination of children aged 3-4 years and 16-17 years, as well as adults and health workers aged 20-29 years, 30-39 years and 40-49 years, an assessment of the level of immunity to hepatitis B is carried out.

5.9. At the discretion of specialists exercising state sanitary and epidemiological surveillance, serological examination for the infections under consideration can be carried out in other age and professional groups.

Recommended "indicator" groups for serological monitoring of the state of herd immunity to diphtheria, tetanus, whooping cough, measles, rubella, mumps, poliomyelitis and hepatitis B are presented in Appendix 2 (Tables 1, 2).

6. Evaluation of the effectiveness and quality of vaccinations

6.1. Assessment of the state of specific immunity of the population to diphtheria, tetanus, whooping cough, measles, rubella, mumps, poliomyelitis and hepatitis B is carried out based on the results of a serological survey of "indicator" groups of the population.

6.2. To assess the actual vaccination and protection of children and adults from diphtheria and tetanus, blood serum is examined in parallel with diphtheria and tetanus antigen diagnosticums. Protected from these infections are persons in whose blood serum antitoxic antibodies are determined in a titer of 1:20 and above.

6.3. When assessing the level of post-vaccination pertussis immunity, those who are protected from whooping cough are persons whose blood serum contains agglutinins in a titer of 1:160 and above.

6.4. Seropositive to measles, rubella and mumps viruses are persons whose blood serum contains specific antibodies at the level specified in the relevant instructions for the test systems.

6.5. When assessing the level of post-vaccination immunity to the hepatitis B virus, persons are protected if their blood serum contains antibodies to HBsAg at a concentration of 10 IU/l or more.

6.6. The intensity of herd immunity to poliomyelitis and the quality of vaccination can be judged on the basis of three indicators:

proportion of persons seropositive for poliovirus types 1, 2 and 3(sera are considered seropositive if the antibody titer is equal to or higher than 1:8; the proportion of seropositive results is calculated for the entire group of examined sera);

proportion of persons seronegative to poliovirus types 1, 2 and 3(seronegative sera are those in which there are no antibodies to one of the types of poliovirus in a 1:8 dilution; the proportion of seronegative results is calculated for the entire group of examined sera);

proportion of seronegative individuals(absence of antibodies to all three types of the virus) are considered persons whose sera lack antibodies to all three types of the polio virus.

An indicator of the strength of herd immunity to poliomyelitis is geometric mean of antibody titer, which is calculated only for the group of sera with antibodies to the corresponding poliovirus serotype in titer 1:8 and above (Appendix 3).

6.7. The results of the serological examination of the contingents are recorded in the working journals of the laboratories indicating the locality, organization, surname, initials, age of the subject and antibody titer. The results are also entered into accounting forms (child development history (f. N 112 / y), outpatient card of the patient (f. N 025 / y), preventive vaccination card (f. N 063 / y), vaccination certificate and other accounting forms.

6.8. The detection in each examined group of children and adolescents of no more than 5% of persons with a diphtheria and tetanus antibody titer of less than 1:20 and no more than 10% of persons with no protective titers of diphtheria and tetanus antibodies in the adult group serves as an indicator of sufficient protection against diphtheria and tetanus.

6.9. The criterion for epidemiological well-being in whooping cough should be the identification of no more than 10% of persons in the examined group of children with an antibody level of less than 1:160.

6.10. The criteria for epidemiological well-being in measles and rubella is considered to be the detection in each "indicator" group of no more than 7% of seronegative individuals.

6.11. Among those vaccinated against mumps, the proportion of seronegatives should not exceed 10%.

6.12. The detection in each surveyed group of no more than 10% seronegative to each of the three serotypes of the poliomyelitis virus is an indicator of sufficient protection against poliomyelitis.

6.13. Among those vaccinated against hepatitis B, the percentage of individuals with an antibody concentration of less than 10 IU / l should not exceed 10%.

6.14. If any "indicator" group is found below the indicated indicators:

more than 5% of individuals among children and adolescents and more than 10% of individuals among adults with a diphtheria and tetanus antibody titer below a protective level;

more than 10% of individuals with anti-pertussis antibody titers below the protective level;

more than 7% of persons seronegative for the measles and rubella virus;

more than 10% seronegative among those vaccinated against mumps;

more than 10% of individuals seronegative for each of the three serotypes of the polio virus;

more than 10% of persons who are seronegative to the hepatitis B virus, with the concentration of antibodies to HBsAg less than 10 IU/l

necessary:

analyze the vaccination documentation for identified seronegative individuals to establish the fact of the presence of vaccination - compare information about vaccinations in all accounting forms (prophylactic vaccination card (f. N 063 / y), history of the child's development (f. N 112 / y), outpatient card of the patient (f. N 025 / y), work journals and others);

assess the conditions of storage and transportation of vaccines, the procedure for immunization;

additionally check the state of immunity to diphtheria, tetanus, whooping cough, measles, rubella, mumps, poliomyelitis and hepatitis B in persons of the same age in the amount of at least 100 people, but in 2 other teams of the same healthcare organization, where a high proportion of seronegative persons;

vaccinate identified seronegative individuals in accordance with applicable regulations.

6.15. If, after an additional examination, the number of those unprotected to these infections exceeds the above criteria, it is necessary to check the availability of vaccinations in people of the same age groups with a high proportion of seronegatives, whose medical care is provided by this healthcare organization in order to establish falsification of vaccinations. Identified unvaccinated individuals should be vaccinated in accordance with the current regulatory documents.

6.16. The materials of serological monitoring of the state of herd immunity are summarized for organizations of various types, clinics, district, city (regional center) and the subject of the Russian Federation as a whole (appendix 2, tables 3, 4, 5, 6). Further, for each infection, the results of the serological survey are compared with incidence rates and vaccination coverage, which will confirm the official data on immunization of the population or identify inconsistencies in vaccination coverage with the level of herd immunity.

6.17. Dynamic monitoring of the state of the population's immunity to infections controlled by means of specific prevention makes it possible to timely identify signs of epidemiological distress. The prognosis of the epidemiological situation for each of the observed infections is considered unsatisfactory if there is a tendency to increase the proportion of seronegative ones.

6.18. When the first prognostic signs are detected in any territory, indicating the impending deterioration of the epidemiological situation for any of the infections under consideration, management decisions are made aimed at increasing the level of the immune layer among the population.

Annex 1. Procedure for collection, transportation and storage of blood sera

Appendix 1

1. Technique of taking and primary blood processing

Capillary blood is taken from the finger under aseptic conditions. Before taking blood, the patient's hand is warmed with hot water, then wiped dry with a clean towel. The finger, after wiping with 70° alcohol, is pierced with a sterile disposable scarifier. Blood in a volume of 1.0-1.5 ml is collected directly through the edge of a sterile disposable centrifuge tube with a stopper (or into special microtubes for taking capillary blood). After taking blood, the injection site is lubricated with a 5% iodine solution.

The tube should be numbered and attached to it with a label indicating the registration number, last name, initials, date of blood sampling.

To obtain sera, a test tube with blood is placed in the office where blood was taken, in an inclined (at an angle of 10-20 °) position at room temperature for 20-30 minutes to form a clot, after which the test tube with blood is shaken to separate the clot from the test tube wall .

A list of examined persons is compiled, which indicates the city (district), number of a preschool institution, group, school, class, number of a secondary specialized institution, group, name of the university, faculty, group, registration number, surname, patient's name, date of birth, date vaccinations against diphtheria, tetanus, measles, rubella, mumps, poliomyelitis and hepatitis B, date of blood sampling, signature of the responsible person.

The test tubes, together with the lists, are sent to the clinical diagnostic laboratory of the HPE, where the tubes with blood are left overnight in the refrigerator at a temperature of 4-8 °C.

After separating the serum from the clot (tubes are circled along the inner surface with a sterile Pasteur pipette), it is centrifuged at 1000-1200 rpm for 15-20 minutes. Then the serum is carefully poured or sucked off with a pipette with a pear into sterile centrifuge (plastic) tubes or eppendorfs with the obligatory transfer of the label from the corresponding tube to them.

In the laboratory, serum (without a clot) can be stored in refrigerators at a temperature of (5 ± 3) ° C for 7 days until the study. For longer storage, whey should be frozen at -20°C. Re-freezing of defrosted whey is not allowed. Having collected the required amount of sera, they are sent to the laboratory of the FBUZ "Center for Hygiene and Epidemiology" of Rospotrebnadzor in the subject of the Russian Federation for research.

2. Transportation of serum (blood) samples

Before transporting the collected material from the survey area, it is very important to take precautions: check the availability of the collected information, tightly stopper the tubes, arrange the samples according to their numbers, etc. Lists of the examined persons should be kept at the collection site. Thermal containers (refrigerator bags) are used to transport blood serum. When transporting and storing blood in the winter season, it is necessary to create conditions under which it does not freeze.

When sending samples by rail or air, laboratories must be notified (by telephone, telegram) of the train (flight) number, the date and time of departure and arrival, the number of samples, etc.

Annex 2. Tables

Annex 2


Table 1

"Indicator" groups for serological monitoring of the state of herd immunity to diphtheria, tetanus, whooping cough, measles, rubella, mumps, poliomyelitis and hepatitis B

"Indicator" groups

Diphtheria

Tetanus

Rubella

Epidemi-
mumps

Polio
myelitis

Hepatitis B

1-2 years

On conducting seromonitoring to study the state of immunity of the population to poliomyelitis

Accepted Ministry of Health of the Orenburg region,
Office of Rospotrebnadzor for the Orenburg region
  1. Serological studies to study the state of specific immunity in indicator groups of the population are a mandatory element of the epidemiological surveillance of poliomyelitis and are carried out in order to control the organization and conduct of vaccination of this disease.
  2. In connection with the ongoing circulation of polioviruses in a number of countries in Africa and Asia and the continuing real threat of importing a wild strain of this pathogen into the region, it is extremely important to obtain objective data on the state of population immunity to poliomyelitis.
  3. Pursuant to the sanitary and epidemiological rules SP 3.1.1.2343-08 "Poliomyelitis prevention in the post-certification period" and the Action Plan for 2006-2008. on maintaining the polio-free status of the Orenburg region
  4. We order:

  5. 1. To the chief physicians of the MUZ "TsGB of Buzuluk" and the MUZ "TsGB of Buguruslan", the MUHI "Gai CRH", the MUHI "Novoorskaya CRH":
  6. 1.1. Organize blood sampling for serological testing for poliomyelitis in indicator population groups in accordance with Appendix No. 1: in the years. Buzuluk and Buguruslan in May 2008, in Gaisky, Novoorsky districts - in September 2008.
  7. 1.2. Ensure compliance with the rules for the collection, transportation and storage of blood sera in accordance with Appendix No. 2.
  8. 1.3. Ensure the delivery of blood sera to the virological laboratory of the FGUZ "Center for Hygiene and Epidemiology in the Orenburg Region" from the cities. Buguruslan and Buzuluk until 05/23/2008, Gaisky and Novoorsky districts - until 09/21/2008.
  9. 1.4. Ensure that the results of serological tests for poliomyelitis are included in the relevant medical records.
  10. 2. The heads of the Eastern, North-Eastern, Western, North-Western territorial departments ensure control over the correct formation of population groups subject to serological examination for poliomyelitis, organization and conduct of blood sampling and compliance with the delivery time of the material to the virological laboratory of the FGUZ "Center for Hygiene and Epidemiology in the Orenburg area".
  11. 3. To the chief physician of the FGUZ "Center for Hygiene and Epidemiology in the Orenburg Region" Vereshchagin N.N. ensure the study of blood sera within 7-10 days from the date of their receipt with the presentation of the results of the studies to the Office of Rospotrebnadzor for the Orenburg region and the Orenburg Regional Center for the Prevention and Control of AIDS and Infectious Diseases.
  12. 4. To impose control over the execution of this order on the First Deputy Minister Averyanov V.N. and Deputy Head of the Department of Rospotrebnadzor in the region Yakovlev A.G.
  13. Minister of Health
  14. Orenburg region
  15. N.N.KOMAROV
  16. Supervisor
  17. Office
  18. Rospotrebnadzor
  19. in the Orenburg region
  20. N.E. VYALTSINA

The procedure for selecting children for serological examination for a state of tension of immunity to poliomyelitis viruses

  1. Serological monitoring of herd immunity to poliomyelitis should be carried out in the following indicator populations:
  2. - Group I - children aged 3-4 years who received a full range of vaccinations in accordance with age (vaccination and two revaccinations).
  3. - II group - children aged 14 years who have a complex of vaccinations in accordance with their age.
  4. Indicator groups should not include those who have recovered from poliomyelitis; children who do not have information about vaccinations; not vaccinated against polio; who have had any disease 1-1.5 months before the examination, as some diseases can lead to a temporary decrease in the titer of specific antibodies.
  5. Each indicator group should represent a homogeneous statistical population, which requires the selection of individuals with the same number of vaccinations and the period from the moment of the last vaccination. In this case, this period must be at least 3 months. The size of each indicator group should be at least 100 people.
  6. Optimally, for the examination, 4 teams of the same age group should be selected (2 teams from two medical institutions), at least 25 people in each team. In the case of a smaller number of children of the indicator group in children's groups, the achievement of representativeness of the research is achieved by increasing the number of preschool institutions where these studies will be conducted.
  7. In children's groups, before a serological examination, medical workers should conduct explanatory work with parents about the need to prevent poliomyelitis and determine post-vaccination immunity to them.
  8. The period during which the sera are collected and delivered to the virological laboratory of the Federal State Health Institution "Center for Hygiene and Epidemiology in the Orenburg Region" should not exceed 7 days.

Rules for the collection, transportation and storage of blood serum

  1. 1. Technique of taking and primary blood processing
  2. When conducting serological studies, only one blood sample is required from each included in the observed group. The minimum amount of blood serum required for the study is at least 0.2 ml, it is better to have 1 ml. Therefore, the minimum volume of a blood sample should be at least 0.5 ml; optimally 2 ml. It is better to take blood from a vein, since this method is the least traumatic, allows you to get the right volumes with a minimum level of hemolysis.
  3. Blood from a vein in the amount of 5 ml is taken with a disposable sterile syringe into a sterile tube under aseptic conditions.
  4. If blood sampling from a vein cannot be performed for any reason, the blood is taken with a finger prick. In this way, a sufficient amount of blood for serological studies can be obtained. Blood in a volume of 1.0 - 1.5 ml is collected directly through the edge of a sterile disposable centrifuge tube with a stopper (or into special microtubes for taking capillary blood). Before taking blood, the patient's hand is warmed with hot water, then wiped dry with a clean towel. The finger is treated with a sterile cotton ball moistened with 70% alcohol and pierced with a sterile disposable scarifier. The puncture is done, slightly retreating from the midline, closer to the lateral surface of the finger (the place where large vessels pass). Drops of blood protruding at the puncture site are collected with the edge of a dry, sterile measured centrifuge tube so that the drops flow down the wall to the bottom. To obtain a large amount of blood, it is recommended to lightly massage the sides of the phalanx. In very young children, a blood sample can be obtained by pricking the heel.
  5. After taking blood, the injection site is lubricated with a sterile cotton ball moistened with a 5% iodine solution.
  6. The test tube with blood is closed with a sterile rubber stopper, a strip of adhesive plaster is glued onto the tube, on which the number of the subject is written, corresponding to the serial number in the accompanying document, surname and initials, date of sampling. Before sending to the laboratory, blood can be stored at a temperature of +4 - +8 degrees. With no more than 24 hours.
  7. In the laboratory to obtain serum, a test tube with blood is left in an inclined (at an angle of 10 - 20 degrees) position at room temperature for 30 minutes. to form a clot; after which the test tube with blood is shaken to separate the clot from the test tube wall and left overnight in the refrigerator at a temperature of +4 - 8 degrees. WITH.
  8. After removing the serum from the clot (test tubes are circled along the inner surface with a Pasteur pipette), it is centrifuged at 1000 - 1200 rpm. within 15 - 20 min. Then the serum is carefully poured or sucked off with a pipette with a pear into sterile centrifuge (plastic) tubes or eppendorfs with the obligatory transfer of the label from the corresponding tube to them.
  9. If the laboratory does not have a centrifuge, then the whole blood should be left in the refrigerator until complete clot retraction (separation of the red blood cell clot from the serum) occurs. Carefully, carefully, avoiding damage to the erythrocytes, transfer the serum to another sterile tube provided with a label. The serum should be clear, light yellow in color, without pronounced hemolysis.
  10. Sera entering the laboratory (without a clot) can be stored until research in domestic refrigerators at a temperature of 4 degrees. C within 7 days. For longer storage, whey can be frozen at -20°C. WITH.
  11. 2. Transportation of serum (blood) samples
  12. Before transporting the collected material, it is very important to take precautionary measures: check the availability of the collected information, firmly close the tubes with a stopper, arrange the samples according to their numbers, put the sera in a plastic bag.
  13. For transportation of blood (serum), thermal containers (refrigerator bags, thermos) should be used. If refrigeration elements are used (they must be frozen), put them on the bottom and sides of the container, then place the plastic bag with the serum samples inside, put the frozen elements back on top. Accompanying documents, indicating the date and time of departure, place in a plastic bag, put it under the lid of the thermal container.
  14. When conducting seromonitoring, blood samples (serum) are accompanied by a neatly completed accompanying document - "List of persons subject to serological examination for the presence of specific antibodies to poliovirus" (attached).
  15. When preparations for shipment are completed, inform the recipient of the time and method of transportation, the number of samples, etc.
  16. Samples are delivered to the virological laboratory of the FGUZ "Center for Hygiene and Epidemiology in the Orenburg Region" (Orenburg, 60 Let Oktyabrya St., 2/1, tel. 33-22-07).
  17. At the place of collection of blood serum samples, duplicates of the lists of examined persons and the results of sera testing should be stored for at least 1 year.
  18. The results are also entered into accounting forms (history of the development of the child, outpatient card of the patient).
  19. List of persons
  20. subject to serological testing for the presence of
  21. specific antibodies to poliovirus (seromonitoring)
  22. (pre) In _____________ in _______ year, city, district

A person is considered protected from disease caused by a particular type of poliovirus if that person has developed type-specific neutralizing antibodies. However, titers of serum neutralizing antibodies that would provide protection against infection have not yet been finally established. In animal experiments, it has been shown that passive transfer of antibodies, accompanied by the appearance of antibodies in moderate titers (1:20 and above), provides protection against the disease. However, these results cannot be extrapolated to the human population in which wild or vaccine strains of poliovirus circulate.

Studies conducted in the 1950s showed that persons with low titers of neutralizing antibodies in the blood serum can be reinfected with wild polio virus. This was confirmed by the results of observation of 237 people with natural immunity to poliomyelitis and neutralizing antibody titers of 1:40 or less during familial outbreaks of polio in Louisiana in 1953-1957. Cases of reinfection, proven by a fourfold increase in serum antibody titers, were registered in 98% of the examined. In contrast, out of 36 people with neutralizing antibody titers of 1:80 to above, cases of reinfection were noted only in 33% of the examined.

Recent studies in Japan and the UK have shown that people with low post-vaccination titers of serum neutralizing antibodies may develop reinfection after being infected with the poliovirus vaccine strain. In Japan, during a 5-year follow-up of 67 children vaccinated with two doses of trivalent PPV, 19 children had titers of antibodies to type 1 poliovirus 1:8 or lower. After the introduction of a resolving dose of PPV, 18 of 19 children in this group developed reinfection, as indicated by the shedding of the polio virus in the faeces. In the UK, a study was conducted in a group of 97 children who, 8-16 years after being immunized in early childhood with three doses of trivalent OPV, were given a new (“permissive”) dose of the same vaccine. In 17 children of this group, before the introduction of a new dose of vaccine, antibody titers to all three serotypes of poliovirus were low (mean geom. antibody titers ranged from 1:9 to 1:36). Although the number of children in this group is too small to draw statistically reliable conclusions, nevertheless, it should be noted that out of 8 children without an immune response to the introduction of a new dose of vaccine, seven had neutralizing antibody titers of 1:32 or more. At the same time, in children who responded with seroconversion to the introduction of a new dose, antibody titers before vaccination were low.

These findings are consistent with previous studies showing that children with low serum antibody titers can be re-infected with the vaccine strain of poliovirus. These studies suggest that people with low but still detectable serum antibody titers do not have an increased risk of developing symptomatic forms of poliomyelitis. However, they can be reinfected with polio virus and serve as sources of infection for people who have not been immunized.

The local barrier to polio viruses is provided by secretory IgA antibodies. Until now, the level of secretory IgA antibodies that would provide protection against infection remains unknown. The relationship between serum and secretory antibody titers is also unknown. Children may be resistant to reinfection with poliovirus even in the absence of serum antibodies when they have secretory antibodies in high enough titers.
In 1955, J. Salk formulated his concept of "increased immunological reactivity", which can prevent deaths from polio even after the use of not very high-quality vaccines. As this concept has evolved, it has been suggested that even after neutralizing antibody titers fall below the minimum detectable level, immunological memory will persist for an indefinitely long period of time, with the result that repeated immunological stimulation with a vaccine or reinfection leads to a rapid and significant increase in antibody titers. It has been suggested that this secondary immune response to infection develops rapidly enough to protect the individual from developing the paralytic form of the disease.

JSalk suggested that lifelong immunity to polio could be induced by a single dose of inactivated polio vaccine (IPV) given to a child between 5 and 7 months of age. However, since this publication, cases of paralytic poliomyelitis have been reported in people who received one or more doses of enhanced-potency IPV (uIPV). Moreover, the protective efficacy of a single dose of uIPV (39%) was found to be almost equivalent to the level of neutralizing antibodies induced by a single administration of this vaccine.

note
Consulting a doctor is the key to your health. Do not neglect personal safety and always consult a doctor on time.