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.     

Evaluation of the immunological effectiveness of the planned vaccinal prophylaxis of diphtheria and tetanus in Sverdlovsk and Sverdlovsk Province

The level and intensity of antitoxic immunity to diphtheria and tetanus in children and adolescents were determined. The presence of tetanus antitoxin in titers exceeding the protective level in 96.3-98.5% of the examined children and adolescents is indicative of a high actual coverage by immunization. Protective titers against diphtheria were lower. There was no essential difference in the levels of protection in children immunized according to the vaccination schedule and in those immunized with some deviations from this schedule. A considerable part of newborns and children aged 3 months had antibodies to diphtheria and tetanus antitoxins. After the third booster immunization changes in antidiphtheria immunity characteristics occurred only in 2.5% of the vaccines and no changes in antitetanus immunity characteristics were observed.     

Epidemiological and immunological features of tetanus under conditions of long-term planned vaccine prophylaxis

The introduction of mass immunization against tetanus has resulted in the decrease of morbidity rate (5.2 times), the leveling of morbidity rate among the urban and rural population and among males and females, though no essential effect on the seasonal distribution of tetanus morbidity has been observed. Persons over 50 years of age (housewives and pensioners) have become the main groups of risk at the post-immunization period. Mass immunization against tetanus over a period of many years has ensured the existence of a sufficient immune stratum (89.9 +/- 3.0% to 100 +/- 3.0%) and a sufficient level of antitoxic immunity (means geom equal to 6.72-9.6 I.U./ml) among children. Among adults, the proportion of persons protected from tetanus decreases in older age groups from 82.1 +/- 1.3% in persons aged 31-40 years to 22.1 +/- 2.0% in persons over 60 years. The observed differences between the coverage of the population with immunization and the proportion of persons having protective titers of tetanus antibodies require constant control of the intensity of immunity and its correction with regard to its initial level, especially in persons of older age groups.     

Immunity to diphtheria and tetanus in some of the administrative territories of the RSFSR

The article deals with the state of immunity to diphtheria and tetanus among the adult population in some administrative regions of the RSFSR. Of the children and adults covered by the survey, 91.3-96.7% were found to have protective antibody titers against diphtheria and 98.7-100%, against tetanus. An essential drop in the level of immunity to diphtheria in persons over 18 years of age was revealed: 71.7% of them were nonimmune, which correlated with the high morbidity rate among these persons. At the same time the percentage of adults nonimmune to tetanus was considerably lower than that of adults nonimmune to diphtheria, reaching only 27.1%. The state of immunity to tetanus in adults was found to depend on the seasons.     

Immunological structure of the population in a system of epidemiological surveillance of diphtheria

The characteristics of antitetanus and antidiphtheria immunity in children, adolescents and adults in Perm have been determined by means of the passive hemagglutination test, and the tendency towards the decrease of their immunity to diphtheria with the increase of their age has been established. The registered and actual coverage of children and adolescents by immunization is characterized on the basis of the presence of antibodies to the tetanus component of combined vaccines. A considerable proportion of persons at boarding schools and vocational technical schools has been found to be seronegative with respect to diphtheria. The seasonal dynamics of antitoxic immunity is presented.     

Antitetanus and antidiphtheria immunity in newborns

The level of antitetanus and antidiphtheria immunity was evaluated in 280 pairs (mother-newborn) and in 56 pairs where mothers (aged 19-26 yrs.) were vaccinated in the 7th month of pregnancy with an adsorbed tetanus vaccine dose. The results revealed a high antitetanus immunity level both in mothers and newborns (93.57% and 92.85% respectively) and a low antidiphtheria protection level (79.64% and 77.14%). Immunization of pregnant women ensures a 100% passive protection of newborns against tetanus before administration of the first vaccine doses. The data obtained also proved that placental transfer of the specific circulating antibodies was high (98.58% and 95% for diphtheria). The high percentage of newborns susceptible to diphtheria toxinfection points to the need to immunize mothers-to-be with low combined diphthero-tetanus (d-T) vaccine doses and to closely observe vaccination programme (Ministry of Health) of children with combined diphthero-tetanus-pertussis vaccine (CDTPV) at an early age (two months).     

Immune response in adult immunized with adsorbed DT-M anatoxin with reduced antigen content and Imovax-DT-adulte vaccine

The comparative study of immune response after immunization of adults with adsorbed DT toxoid with reduced antigen content and Imovax-DT-adulte vaccine, as well as the safety of these preparations, was made. The study revealed that immunization of adults with adsorbed DT toxoid having reduced antigen content, made in two injections, and the injection of Imovax-DT-dulte vaccine, as well as the successive injection of these preparations, produced the same the levels of antitetanus immunity. Antidiphtheria immunity, evaluated by the number of seroconverted to diphtheria persons following two injections immunization was similar for the two preparations, while the level of antidiphtheria antibodies was higher in persons immunized with adsorbed DT toxoid. The immune stratum index was rather high among persons aged 16-29 years. This age group exhibited the highest number of persons, seropositive to both diphtheria and tetanus. Both vaccine preparations, adsorbed DT toxoid with reduced antigen content and Imovax-DT-adulte vaccine, were found to be equally capable of inducing autoimmune reactions in the vaccinees, detected by laboratory methods.     

Booster vaccination against tetanus and diphtheria: insufficient protection against diphtheria in young and elderly adults

We have recently demonstrated that single shot vaccinations against tetanus and diphtheria do not lead to long-lasting immunity against diphtheria in elderly persons despite administration at 5 year intervals. In the present study we have immunized a group of young adults against tetanus and diphtheria to compare the pre- and 28 days post-vaccination immune responses in the young group with results of the same vaccination performed in an elderly group of a previous study. We also studied protection in both groups 5 years after vaccination. We compared antibody titers at all three time points and also analyzed the T cell responses in both age groups 5 years after vaccination.Before vaccination 9 % of the elderly persons were not protected against tetanus, and 48 % did not have protection against diphtheria. In the young group all participants were protected against tetanus, but 52 % were also unprotected against diphtheria before vaccination. 28 days after vaccination 100 % of all participants had protective antibody concentrations against tetanus and only a small percentage in each age group (<10 %) was unprotected against diphtheria. 5 years later, 100 % of both cohorts were still protected against tetanus, but 24 % of the young and 54 % of the elderly group were unprotected against diphtheria. Antibody concentrations against diphtheria measured by ELISA correlated well with their neutralizing capacity. T cell responses to tetanus and diphtheria did not differ between young and old persons. We conclude that booster vaccinations against tetanus and diphtheria according to present recommendations provide long-lasting protection only against tetanus, but not against diphtheria, independently of age. In elderly persons, the level of protection is even lower, probably due to intrinsic age-related changes within the immune system and/or insufficient vaccination earlier in life.     

Experimental imutiol stimulation of the primary immunological response to tetanus anatoxin]

The data on the influence of imuthiol on humoral and cell-mediated immunity developing after immunization against tetanus are presented. Experiments were made on 166 guinea pigs with the use of imuthiol in doses of 25 and 125 mg/kg and tetanus toxoid in doses of 1.5 and 6.0 BU/kg. The dynamic observation of the animals lasted 30 days. The data of the passive hemagglutination test and the neutralization test indicated that imuthiol had considerable influence on the formation of humoral immunity. The results of skin reactions with tetanin, in vitro cell reactions, as well as resistance tests, showed that imuthiol exerted influence on delayed hypersensitivity, the mechanisms of cell-mediated resistance and survival after challenge. The data on the influence of imuthiol could be registered even at early stages after immunization, the immunostimulating action of the preparation reaching its maximum with tetanus toxoid used in a dose of 6.0 BU/kg and imuthiol, in a dose of 125 mg/kg.     

The antidiphtheria and antitetanus immunities of children of the Maritime Territory after the use of adsorbed DTP vaccine and adsorbed DT-m anatoxin]

The state of collective immunity to diphtheria and tetanus in children of preschool age, depending on the kind of vaccine preparation used for immunization, was studied. The immunological potency of adsorbed DPT vaccine (i.e. its capacity of forming prolonged and stable basic immunity) was shown to be higher in comparison with the potency of adsorbed DT toxoid with reduced antigen content (DT-R). The study revealed that in all groups of children the level of antitetanus immunity was higher than the level of antidiphtheria immunity, and 3 years later its decrease was less pronounced. A stricter approach to giving medical grounds for the use of low-reactive adsorbed DT-R in the immunization of children belonging to groups of risk is recommended.     

Reactivity, immunogenicity and epidemiological effectiveness of vaccination according to various schemes of immunization against whooping-cough, diphtheria and tetanus]

An extended controlled epidemiological trial was carried out for the purpose of studying the reactogenic properties, immunological and epidemiological efficacy of immunization against whooping cough, diphtheria and tetanus according to a scheme suggested by the authors (AKdeltaC-AKdeltaC-KB) in comparison with the official scheme (AKdeltaC-AKdeltaC-AKdeltaC). There was revealed some increase in the frequency of general reactions in children vaccinated by the experimental scheme; however strong general reactions and local reactions of different intensity were encountered with equal frequency in both groups. Two months after the end of the vaccination significantly higher titres of pertussis agglutinins were revealed in children immunized by the AKdeltaC-AKdeltaC-KB scheme; no significant difference was found in the content of the protective titres of diphtheria and tetanus antitoxins. The duration of preservation of postvaccinal antibodies against all the AKdeltaC-vaccine components and increase in their amount after the first revaccination (in 1.5-2 years) was the same in both the groups of children. A greater epidemiological efficacy of pertussis antigen was revealed by prolonged observation in immunization by the AKdeltaC-AKdeltaC-KB sheme in comparison with immunization by the official scheme (pertussis incidence per 100 thousand children proved to be 12.7 and 71.2, respectively).     

The expediency and feasibility of abolishing the use of antitetanus serum for injuries in the Arkhangel'sk region]

The use of antitetanus serum (ATS) in the north taiga soil-vegetative zone and farther to the north is inexpedient because of an insignificant contamination of soil with B. tetani and a trivial contact of the population with soil. In the Arkhangelsk region with a high incidence of trauma and a low tetanus morbidity the damage caused to the population by the administration of ATS in the form of serum sickness (1.1% of the persons given ATS injections) and anaphylactic shock considerably exceeded the value of negative results of the infection. In the presence of immune population (over 86% of the children and 82% of adults are immune) and with additional vaccination of definite groups it is not only possible, but necessary to suspend ATS injections in trauma; instead, 0.5 ml of tetanus toxoid should be used for revaccination. Suspension of ATS application in trauma gives marked economy of the budget of the public health of the region.     

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.     

Antidiphtheria and antitetanus antitoxic immunity indices in the population of the Estonian SSR (an assessment of the effectiveness of a planned vaccine prophylaxis)]

In 1972-1974 and 1977 in the Estonian SSR children and adults were surveyed for the presence of antibodies against tetanus and diphtheria toxins (toxoids) by means of the passive hemagglutination test. The level of protection against tetanus was revealed to correspond to the proportion of child population covered by vaccination: in 1977, with 98.8% covered by vaccination, the level of protection among children aged 7 to 14 years and adolescents of 15-19 years exceeded 98%; with the increase of age (every 10-15 years) the level of protection against tetanus regularly decreased. This dynamics correlated with the existing terms of postvaccinal immunity and the epidemiological independence of tetanus as infectiion. The level of protection in child population against diphtheria in 1972-1974 and 1977 lagged behind the level of protection against tetanus and the coverage by vaccination. The diphtheria component of adsorbed DPT vaccine seemed to be unable to ensure the sufficient level and intensity of immunity under conditions of a sharply decreased risk of encounter with the infective agent. In persons aged 40 years and over the indices of immunity against diphtheria were higher than against tetanus. These indices resulted from diphtheria infection at the prevaccination period and could serve as an objective sign in following up the decrease of the process of diphtheria epidemics.     

Total immunization of children against influenza decreases morbidity in a number of diseases among elderly persons during influenza epidemic

Immunization of children aged 3-6 years in kindergartens and school children aged 7-17 years against influenza with inactivated influenza vaccine was carried out in two districts of the Moscow region. The comparison of morbidity in influenza-like diseases among the immunized children with that among nonimmunized children in control districts revealed that the effectiveness of immunization was 60.9% in kindergartens and 68.8% in schools. The analysis of morbidity in a number of diseases among 158,451 elderly persons not immunized against influenza demonstrated that, in comparison with the control districts, in those districts where mass immunization of children was carried out morbidity in influenza-like diseases among elderly persons was 3.4 times lower and, out of other 10 diseases under study, morbidity in 8 diseases was 1.5-2.6 times lower. As indicated by the data obtained in this study, total anti-influenza immunization of children in organized groups not only essentially decreased influenza morbidity among children, but also greatly decreased morbidity in influenza and a number of diseases, appearing as complications of influenza infection, among nonimmunized elderly persons during influenza epidemic.     

Efficacy of the per os immunization and reimmunization of man with staphylococcal anatoxin]

By double immunization of 72 persons and single reimmunization of 38 persons per os with tablets containing 100 BU of purified concentrated staphylococcus toxoid (PCST) it was revealed that this immunization was harmless and the immunological response was adequate. The tablets were intended for application through the oral mucosa (oral) or the intestinal tract (enteral); the immunological response depended on the dose of the preparation and the scheme of administration. A high sensitization of healthy persons examined to staphylococcus was found. There was a tendency to reduction of hypersensitivity after the immunization with staphylococcus toxoid (examination in 6 months) and activation of reactions after the antigen administration (examination in 14 days).     

Possibility of peroral revaccination against tetanus]

The authors present the results of oral revaccination of volunteers by purified tetanus toxoid. It appeared that in a dose of 500 BU tetanus toxoid covered with no special coat, produced no immunological effect. As to the coated toxoid-the same dose produced and increase in the antitoxin titre to the protective level, and greater.     

Variants in the immune response to revaccination with diphtheria anatoxin in adults

The immunological effectiveness of the revaccination (made in two injections) of 488 adults aged 18-67 years with diphtheria-tetanus toxoid is discussed; the parallel study of the results of this revaccination was carried out in the diphtheria toxin neutralization test on Vero cells and in the passive hemagglutination (PHA) test. The specific features of the dynamics of the increase of diphtheria antitoxic antibodies, depending on the initial immunity level, the age and the sex of revaccinated persons, were determined. Among persons with the low level of circulating antibodies before revaccination four variants of immune response to the injection of diphtheria toxoid were registered: variant 1--rapid reaction like in secondary immune response (53.6%); variant 2--delayed but effective reaction like in primary immune response (27.3%); variant 3--slow weak response (6.5%); and variant 4--the absence of effective immune response to immunization made in 2-3 injections (12.6%). The immunological and neutralizing properties of diphtheria antitoxic antibodies in the process of immunization made in 2 injections were evaluated. Persons with abnormal immune response (variants 3 and 4) produced defective antibodies, displaying immunological activity in the PHA test, but in most cases unable to neutralize diphtheria toxin in vitro when tested on Vero cells.     

Combined Active-Passive Immunization Against Tetanus in Man

A schedule for the prevention of tetanus in the injured, which has been in operation in the emergency department of a large hospital for over two years, is proposed. For the majority of nonimmunized persons, it is recommended that a dose of toxoid and 50 units tetanus immune globulin (human) (TIGH) be given, in separate sites, to be followed later by additional doses of toxoid for the completion of active immunization. Combined active-passive immunization with tetanus toxoid and 50 units TIGH gives a low level of passive immunity and stimulates early onset of active immunization. In combined active-passive immunization, adsorbed tetanus toxoid produced a significantly higher response than the fluid toxoid. The injection of 400 units TIGH somewhat suppressed the induction of immunity following the first dose of AlPO₄-tetanus toxoid.     

Humoral imunity to pertussis in children with diabetes of type 1

To determine the state of humoral immunity to pertussis in children with insulin-dependent diabetes, IgG antibodies to pertussis toxin (PT) were determined in blood serum samples by means of EIA. In a group of children aged up to 6 years the highest percentage (100%) received the complete course of vaccination against pertussis with Russian adsorbed DPT vaccine, containing whole-cell pertussis monovaccine, while in a group over 6 years the complete vaccination course (3 vaccinations and 1 revaccination) had 53.4% of children. Pertussis morbidity was considerably higher in nonvaccinated subjects than in children with 4-fold vaccination (p < 0.001). The coefficient of association (Q) was 0.84. Children of all age groups were found to have low and average titers of antibodies to PT. The regressive analysis showed a decrease in antibodies in persons completely immunized against pertussis by the age of 6 years old. The presence of antibodies in nonimmunized persons showed that cases of pertussis or carrier state took place among the population. High titers of antibodies, indicative of recent cases of pertussis, were registered in all age groups, but high titers of antibodies were registered mostly in the group of children over 13 years old (p < 0.05), which confirmed an increase in pertussis morbidity in adolescents. Thus, vaccination against pertussis effectively protected children with diabetes of type 1, aged up to 6 years. For more prolonged protection the vaccination and revaccination of children aged over 4 years old is necessary.