Immunostructure of school-age children inoculated against measles

The mass serological survey of school children immunized against measles was carried out by means of the hemagglutination inhibition test. As a result, 20.4% of these school children were found to be seronegative, and in 9.5% of them even the minimum concentration of measles antihemagglutinins (when titrated with 1 hemagglutinating unit of the antigen) was not detected. The accumulation of a considerable seronegative (measles-susceptible) stratum among children of school age occurred due to the low immunogenic potency of some batches of live measles vaccine, used for immunization in 1973, as well as due to the formerly practiced immunization of children under 1 year of age. A direct and close dependence of focal measles morbidity among immunized children having had contacts with the source of infection on the number of children among them, found to be seronegative after titration with 1 hemagglutination unit of measles antigen, was established.     

Measles morbidity among children inoculated against this infection

In the serological survey of 2009 children immunized against measles 285 children (14.2%) were found to be seronegative to this infection in the hemagglutination inhibition test with 4 hemagglutinating units of the antigen. Among 1724 immunized children showing positive response to vaccination and placed under dynamic observation for 11 years, 2 cases of measles were registered. At the same time, in the dynamic observation of 111 seronegative children 66 measles cases (59.5%) were registered during the above period, while among 169 children, also seronegative, but receiving booster immunization against measles, morbidity rate was only 1.2%. In some vaccinees the decrease of postvaccinal immunity to seronegative values was observed, but such decrease had no essential influence on the morbidity level among the vaccines. The increase of measles morbidity among schoolchildren immunized against this infection was due not to the decrease of their postvaccinal immunity, but to their concentration in schools and to their more intensive contacts with the sources of infection in comparison with children of preschool age.     

The duration and intensity of measles immunity after a repeat inoculation against this infection

Controlled study lasting 6 years showed that booster immunization against measles was highly effective in children remaining seronegative, i. e. susceptible to this infection, after primary immunization: E = 97.5 +/- 0.12% (K = 35.7). Annual serological examination of children given booster immunization revealed that 87.6% of initially seronegative children retained specific antihemagglutinins for 5.5 years (the term of observation). The effectiveness of booster immunization against measles did not depend on the age when primary immunization had been made.     

The duration and strength of postvaccinal measles immunity

A prolonged immunoepidemiological follow-up of a large group of children immunized against measles revealed a high epidemiological efficacy of a single vaccination. Cases of measles were registered only among those vaccinees in whose blood sera no specific hemagglutinins were detectable by titration with 4 hemagglutinating units of measles antigen prior to the disease. The study showed that groups of children seronegative with respect to measles appeared, as a rule, after unsatisfactory immunization and not due to loss of postvaccinal immunity with time. Properly immunized children in whom the formation of antimeasles antibodies had occurred in response to the injection of live measles vaccine retained postvaccinal immunity for more that 15 years (the term of observation).     

Transplacental measles immunity in infants in the 1st year of life]

A total of 187 parturients (66 with a history of measles and 121 immunized with live measles vaccine, or LMV, in childhood) and their 187 newborn infants, as well as 195 children aged up to 1 year, were examined. Antimeasles antibodies in blood sera were detected in the hemagglutination inhibition test. In all mothers with a history of measles and in their newborn infants antimeasles antibodies in different titers were detected. In mothers, formerly immunized with LMV, antimeasles antibodies were absent in 5.8% and in their newborn infants, in 6.6% of the examinees. Among children aged up to 1 year, born of formerly immunized mothers, more rapid disappearance of passive antimeasles immunity was observed. In cases of contact with measles, the serological examinations of all children born of mothers immunized with LMV should be carried out in order to protect seronegative children by passive or active immunization.     

Assessment by immunoenzyme analysis of the immune status of donors with reference to the viruses of rubella, measles and herpes simplex

The results of testing the blood sera obtained from donors at a blood transfusion center in Moscow for the presence of antibodies to rubella, measles and herpes simplex viruses, carried out by means of the enzyme immunoassay with the use of the corresponding test systems, are presented. Antibodies to rubella, measles and herpes simplex viruses have been detected, respectively, in 81.5, 96.7 and 100% of blood sera. The proportion of sera with low, medium and high antibody titers has proved to be virtually the same with respect to antibodies to rubella and herpes simplex viruses, the sera with medium antibody titers constituting 59%. At the same time tests for measles antibodies have shown the prevalence of sera with low titers (49.2%) with the highest percentage of seronegative donors (18.5%, as compared with 3.3% in rubella and the absence of negative sera in herpes simplex).     

The use of the cluster selection method for assessing the status of immunity to controlled infections (measles, diphtheria and tetanus)]

The use of the method of cluster selection in mass serological examination makes it possible to obtain statistically significant results with very low expenditures. The coincidence of the results on the number of seronegative children, obtained by the method of cluster selection, with the results of mass serological examination of all children aged 6-7 years in the district (children found to be seronegative to measles constituted 5.5% and 5.0% respectively) is indicative of the statistical significance of the method used in this investigation. The results obtained by the method of cluster selection indicate that the level of protection among the children of the district was high both with respect to measles (94.5 +/- 1.8%) and tetanus (96.5 +/- 1.7%); with respect to diphtheria, the immune stratum was found to be less (91.1 +/- 2.3%). These data may be helpful in working out scientifically substantiated administrative decisions contributing to an increase in the effectiveness of planned mass immunization.     

Subacute sclerosing panencephalitis in Croatia (1994-2004)

We studied five patients with SSPE during a 10-year period (1994-2004). The first clinical symptoms developed at the age of 5-11 years. All patients were vaccinated regularly against measles according to the official immunization schedule. One patient had measles at the age of 18 months. Two of them had a history of morbilliform rash (unrecognized measles) at the age of six and seven months, respectively. In two patients, with no history of measles before vaccination the disease started after varicella infection. Using complement-fixation (F) test and EIA, antibodies to measles virus (MV) were detected in the CSF and sera of all patients. The CF-antibody titers ranged from 1:1024 to 1:65536 in sera and from 1:16 to 1:128 in CSF samples. MV antigen was detected in brain imprints using IFA in two patients. Electron microscopic analysis revealed intranuclear viral inclusions (MV nucleocapsids). Using RT-PCR, viral RNA was found in both patients. Nucleotide sequence analysis showed that the viruses found in the brain tissue belonged to the wild-type MV D6 genotype [7].     

吸附无细胞百日咳菌苗、白喉、破伤风类毒素混合制剂Ⅲ期临床人体接种反应和血清学效果观察报告

吸附无细胞百、白、破混合制剂（ＤＴａｃＰ）于１９９５年６月至１９９７年９月在广东省４个市和陕西省大荔县进行了Ⅲ期临床人体接种反应和血清学效果观察,全程基础免疫婴幼儿６４９６１例,加强注射３８８６０例,总计为１０３８２１例,接种反应轻微,未发现有严重异常反应者。ＤＴａｃＰ在基免后１年和加强注射前抗ＰＴ和抗ＦＨＡ的抗体水平分别为１０１ＥＵ／ｍｌ和５１３ＥＵ／ｍｌ;加强注射后１个月,抗ＰＴ和抗ＦＨＡ的抗体水平显著增长,分别为２４３４ＥＵ／ｍｌ和３１１３ＥＵ／ｍｌ;加强免疫后１年,抗ＰＴ和抗ＦＨＡ的抗体水平均能维持在较高的抗感染水平,分别为２０１ＥＵ／ｍｌ和５８６ＥＵ／ｍｌ;ＤＴａｃＰ抗白喉和抗破伤风的抗体水平,不论是在基免后还是在加强注射后１个月或１年,其≥００１ＨＡＵ／ｍｌ的例数均为１００％,均显著超过儿童抗白喉和抗破伤风感染要求的保护水平（００１ＨＡＵ／ｍｌ）。     

Use of the leukocyte adherence inhibition reaction for assessing the effectiveness of vaccination against measles

The reaction of the inhibition of leukocyte adhesion to a glass slide under the action of measles antigen may be used for the evaluation of the activity of antigen-specific T-lymphocytes in the process of immunization against measles and recommended, along with serological studies, for finding out persons susceptible to measles among vaccinees. The immunological effect of booster immunizations against measles can be evaluated by the degree of the inhibition of leukocyte agglutination to a glass slide.     

Effectiveness of revaccination against measles]

The authors studied the efficacy of measles revaccination in children in whose serum no specific antihemagglutinins were revealed in titration with 1 GAE antigen (the first group) and having no specific antibodies in titration with 4 GAE antigen (the second group). Investigations demonstrated that children in whose blood serum no measles antibodies were revealed in the presence of 1 GAE antigen were subject of vaccination. Repeated vaccination used at present in persons who produced minimal antibody concentrations in response to vaccination is not recommended.     

Effectiveness of measles immunoprophylaxis and the criteria for assessing its possible elimination

The study of measles morbidity in Donetsk Province in 1960-1984 and the study of antimeasles immunity in different groups of the population have shown that the problem of the liquidation of measles cannot be solved by immunizing the population in a single administration of the vaccine. To enhance the effectiveness of the immunoprophylaxis of measles and its influence on the epidemic process, a number of problems must be solved with the aim to improve the quality of the vaccine, especially its thermal stability, to establish the possibility of shifting the beginning of immunization from 15-17 months to 12 months of age, to increase the coverage of children with immunization against measles by decreasing the number of groundless exemptions from immunization and by immunizing children in risk groups according to individual schedules and dosage, to carry out selectively the booster immunization of persons who have lost their postvaccinal immunity, as revealed by laboratory test, or in whom such loss may be supposed, to introduce the objective method (indirect hemagglutination test) for controlling the state of immunity among different groups of the population into laboratory practice at sanitary and epidemiological stations. As to the possibility of the liquidation of measles, the statement of this problem is correct, but for its solution a complex of additional prophylactic and epidemic-control measures should be taken.     

Use of adsorbed diphtheria-tetanus (DT) toxoid containing different doses of antigens in booster immunizations of children

To decrease the antigenic load in booster immunizations of children against diphtheria and tetanus, the immunological effectiveness and reactogenicity of different doses of both antigens (i. e 1 Lf and 1 BU; 2.5 Lf and 2.5 BU; 5 Lf and 5 BU) were studied. The study revealed that all these doses of the preparation were practically nonreactogenic: the total of systemic reactions was 0.9%. The study of the immunological effectiveness of adsorbed DT toxoid with reduced antigen content revealed the advantage of the commercial dose of the preparation (5 Lf of diphtheria antigen and 5 BU of tetanus antigen) over such doses of diphtheria and tetanus antigens as, respectively, 1 Lf and 1 BU; 2.5 Lf and 2.5 BU. Still, this advantage disappeared as early as 6 months after booster immunization. The results of these investigations indicate that booster immunization of children aged 6 years and over may be made with lower doses of adsorbed DT toxoid with reduced antigen content.     

Postinfection and postvaccinal antianthrax immunity in human subjects

Antibodies to Bacillus anthracis protective antigen (PA) and to the lethal factor (LF) of B. anthracis exotoxin in the blood sera of anthrax patients and of subjects with a history of the disease, as well as of persons immunized with STI live vaccine, were studied by the heterogeneous enzyme immunoassay. In 1-6 years after convalescence the levels of anti-PA and anti-LF antibodies (at 75% and 96% detection rates respectively) were higher than on weeks 1-4 from the onset of the disease. In persons having had anthrax antibodies belonged mainly to IgG, and the anti-LF antibody level was higher than the anti-PA antibody level. In persons immunized with STI vaccine the detection rate of antibodies somewhat increased in 2-7 months after immunization, reaching, on the average, 72%, the antibody levels after primary immunization and regular annual booster immunization being similar. In 1-2 years after primary (booster) immunization the isolation rate of antibodies decreases to 21%. Specific features of postinfectious and postvaccinal immunity to anthrax and problems of retrospective diagnosis of this disease are discussed.     

Immune Response against Hamster Erythrocytes in the Low-Responder Mouse Strains

The production of anti-hapten antibody after immunization with trinitrophenylated (TNP) hamster erythrocytes (HRBC) or sheep erythrocytes (SRBC) was determined in high- and low-responder mouse strains against HRBC antigen. 1) Anti-TNP antibody was detected in sera of high-responder DDD and CF1 mice after primary immunization with TNP-HRBC, but not in those of low-responder C57BL/6 mice. 2) Anti-TNP antibody was detectable in sera of all the strains after primary immunization with TNP-SRBC. 3) Production of anti-TNP antibody was elicited after a booster injection of TNP-HRBC in low-responder C57BL/6 mice pre-sensitized with HRBC in Freund's complete adjuvant. These results suggest that functions of thymus-derived cells specific for HRBC antigen are deficient in low-responder mice.     

Vaccination against measles, mumps and rubella (MMR): a comparison between the antibody responses at the ages of 18 months and 12 years and between different methods of antibody titration

In connection with the introduction of the trivalent vaccine against measles, mumps and rubella at 18 months and 12 years of age, an evaluation of the seroconversion and booster effects in the two age-groups was carried out. This also comprised different laboratory-test methods appropriate for follow-up studies after large-scale, vaccination studies. The measles, mumps and rubella antibodies were measured by the haemolysis-in-gel (HIG) method. Measles antibodies were also measured by the haemagglutination-inhibition (HI) test. Borderline values or samples negative to measles or mumps were also tested by the serum-neutralization (SN) test. All but four of 150 18-month-old children lacked antibodies against measles by the HI test and one of these by the HIG method. Against mumps, 99% were seronegative in the HIG test and 97% in the SN test and two against rubella prior to vaccination. Among 247 schoolchildren, 60 (24%) lacked antibodies in the HI test and 28 (11%) of these also in the HIG test. Sixty-six schoolchildren (25%) were negative to mumps and 45% to rubella prior to vaccination. The seroconversion rate for the 18-month-old children was 96% against measles, 93% against mumps and 99% against rubella. The figure for the schoolchildren was 82% against measles, 80% against mumps and 100% against rubella. On comparing the titre levels in seroconverting children, the measles-antibody levels were found to be lower among older children, compared with younger, while the opposite was true for rubella.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiologic effectiveness of mass revaccination against measles

The data on the epidemiological effectiveness of the mass booster immunization of students of high schools, as well as professional and technical schools, against measles are presented. Booster immunization is considered to be a highly effective antiepidemic measure aimed at decreasing morbidity rate in measles.     

Immunological effectiveness of secondary revaccination against tetanus performed at prolonged intervals

After primary immunization with adsorbed DPT vaccine antitetanus immunity was retained for 9-10 years in 90.6-98.4% of children covered by this study. The second booster immunization of children against tetanus with adsorbed DT toxoid with reduced antigen content, made at an interval prolonged to 7-10 years under the conditions of lower antitoxic immunity, ensured a high level of intense antitetanus immunity. These data point to the possibility of prolonging the interval between booster immunizations to 9-10 years and reducing the number of injections and antigenic load.     

Acellular pertussis booster in adolescents induces Th1 and memory CD8+ T cell immune response

In a number of countries, whole cell pertussis vaccines (wcP) were replaced by acellular vaccines (aP) due to an improved reactogenicity profile. Pertussis immunization leads to specific antibody production with the help of CD4(+) T cells. In earlier studies in infants and young children, wcP vaccines selectively induced a Th1 dominated immune response, whereas aP vaccines led to a Th2 biased response. To obtain data on Th1 or Th2 dominance of the immune response in adolescents receiving an aP booster immunization after a wcP or aP primary immunization, we analyzed the concentration of Th1 (IL-2, TNF-α, INF-γ) and Th2 (IL-4, IL-5, IL-10) cytokines in supernatants of lymphocyte cultures specifically stimulated with pertussis antigens. We also investigated the presence of cytotoxic T cell responses against the facultative intracellular bacterium Bordetella pertussis by quantifying pertussis-specific CD8(+) T cell activation following the aP booster immunization. Here we show that the adolescent aP booster vaccination predominantly leads to a Th1 immune response based on IFNgamma secretion upon stimulation with pertussis antigen, irrespective of a prior whole cell or acellular primary vaccination. The vaccination also induces an increase in peripheral CD8(+)CD69(+) activated pertussis-specific memory T cells four weeks after vaccination. The Th1 bias of this immune response could play a role for the decreased local reactogenicity of this adolescent aP booster immunization when compared to the preceding childhood acellular pertussis booster. Pertussis-specific CD8(+) memory T cells may contribute to protection against clinical pertussis.     

Study of combined vaccination against yellow fever and measles in infants from six to nine months

A study has been carried out in the Ivory Coast to assess the efficacy of a combined vaccine against yellow fever and measles relative to that of each vaccine administered separately. Healthy children aged six to nine months were recruited and divided into two age groups: less than seven months (group I) and more than eight months (group II). In each group, they were randomly assigned to receive either yellow fever vaccine only (A), measles vaccine only (B), or the combined vaccine (C). The serological responses to measles and yellow fever were assessed in 219 initially seronegative children 45 days after immunization. More than 90% of the children developed yellow fever haemagglutination inhibiting antibodies. Neither age nor combination with measles vaccine influenced the responses to yellow fever vaccine. Measles haemagglutinational inhibiting antibodies were found in 97% of the children and the seroconversion rate was influenced neither by age nor by combination with yellow fever vaccine. Younger infants had lower titres of measles antibody. No particular adverse reactions were notified during the follow up. This study shows that combined yellow fever and measles vaccines are immunogenic in infants from the age of six months. Controlling yellow fever in endemic areas and the prevention of measles in young infants may greatly benefit by this combination.