A population-based study on tetanus antitoxin levels in The Netherlands

WHO recommendation and India's practice on tetanus vaccination-How much is too much?

Tetanus is one of the dreaded fatal diseases which is of public health importance. Reducing the morbidity and mortality due to tetanus, especially maternal and neonatal, is one of the major aims of health organizations around the world. Vaccination against tetanus is one of the most salient interventions. In order to ensure the unerring vaccination practices, the World Health Organization has been updating its position papers on all vaccines. To enable India to follow the appropriate vaccine policy, this article highlights the category and situation-based schedule of tetanus toxoid vaccination.

Incidence of Tetanus and Diphtheria in Relation to Adult Vaccination Schedules

BACKGROUND

The World Health Organization (WHO) does not recommend routine adult booster vaccination for tetanus and diphtheria after completion of the childhood vaccination series. However, many countries continue to implement adult booster vaccinations, leading to the question of whether this is necessary to reduce the incidence of these 2 rare diseases.

METHODS

We conducted an observational cohort study based on WHO case reports from 2001 through 2016. We compared the incidence of tetanus and diphtheria in 31 North American and European countries that either do or do not recommend adult booster vaccination.

RESULTS

Countries that vaccinate adults every 5-20 years (group 1) were compared with countries that do not routinely vaccinate adults for tetanus or diphtheria (group 2). Comparison of group 1 vs group 2 revealed no significant decline in tetanus incidence rates among countries that vaccinate adults (P = .52; risk ratio [RR] = 0.78; 95% confidence interval [CI], .36 to 1.70). The risk of contracting diphtheria was increased among countries that vaccinate adults due to inclusion of Latvia, a country that had poor vaccination coverage (P < .001). However, if Latvia is excluded, there is no difference in diphtheria incidence between countries that do or do not routinely vaccinate adults (P = .26; RR = 2.46; 95% CI, .54 to 11.23).

CONCLUSIONS

Review of >11 billion person-years of incidence data revealed no benefit associated with performing adult booster vaccinations against tetanus or diphtheria. Similar to other vaccines, this analysis supports the WHO position on adult booster vaccination and, if approved by governing health authorities, this may allow more countries to focus healthcare resources on vulnerable and undervaccinated populations.

Immunity against tetanus and effect of vaccination in Turkey

The immune status against tetanus in relation to vaccination was investigated among healthy populations in 3 selected provinces in Turkey (n=2094). In-house ELISA supplemented with the particle agglutination test was performed for this purpose. An exact correlation was found between vaccination status and immunity against tetanus. The immunity was high among children and sharply decreased with age among adults. The primary vaccination for children increased the immunity, reaching a geometric mean titer (GMT) of 6.2 IU/ml at the fourth dose. There was a reduction of immunity during the next y, followed by an increase with a booster injection at primary school age. Among adolescents and adults, the GMTs after the last vaccination fell off exponentially with a slope of -0.068 log10 IU/ml per y. Extrapolation of the regression line predicted that the minimum protective level (> or =0.01 IU/ml) would be maintained for approximately 30 y on average after the last vaccination. Diyarbakir, 1 of the selected provinces, had lower immunity than the other 2 provinces with poor immunization. Adult females tended to show slightly higher GMTs than males, probably due to the neonatal tetanus elimination program. Reinforcement of immunization against tetanus for adults is recommended.

Tetanus and Pertussis vaccines: their usefulness in the aging population

Immunization is a safe, effective and simple way of preventing life-threatening tetanus infection in children and adults, and is therefore recommended for all age groups in all European countries. In older persons, despite waning immunity with increasing age, the majority of vaccinees attain protective tetanus immunity under a proper vaccination schedule. Based on the scientific evidence, decennial boosters are recommended for elderly persons who have received primary tetanus vaccination in the past. Until recently, pertussis vaccination was understood as an early childhood intervention. Due to decreasing immunity, re-vaccination of youngsters and adults is recommended and is also considered for seniors 60 years and over. Routine immunization of seniors against pertussis every ten years yields a high level of protection of older individuals, and at the same time contributes to epidemiological control of pertussis in the population.

Maternal and neonatal tetanus

Maternal and neonatal tetanus are important causes of maternal and neonatal mortality, claiming about 180 000 lives worldwide every year, almost exclusively in developing countries. Although easily prevented by maternal immunisation with tetanus toxoid vaccine, and aseptic obstetric and postnatal umbilical-cord care practices, maternal and neonatal tetanus persist as public-health problems in 48 countries, mainly in Asia and Africa. Survival of tetanus patients has improved substantially for those treated in hospitals with modern intensive-care facilities; however, such facilities are often unavailable where the tetanus burden is highest. The Maternal and Neonatal Tetanus Elimination Initiative assists countries in which maternal and neonatal tetanus has not been eliminated to provide immunisation with tetanus toxoid to women of childbearing age. The ultimate goal of this initiative is the worldwide elimination of maternal and neonatal tetanus. Since tetanus spores cannot be removed from the environment, sustaining elimination will require improvements to presently inadequate immunisation and health-service infrastructures, and universal access to those services. The renewed worldwide commitment to the reduction of maternal and child mortality, if translated into effective action, could help to provide the systemic changes needed for long-term elimination of maternal and neonatal tetanus.

Immunity to diphtheria and tetanus in Australia: a national serosurvey

OBJECTIVE

To determine immunity to tetanus and diphtheria in the Australian population.

DESIGN AND SETTING

Analysis, using double antigen enzyme immunoassays, of a representative sample of sera (1950 samples tested for diphtheria and 2884 for tetanus) collected opportunistically from Australian laboratories between July 1996 and May 1999.

MAIN OUTCOME MEASURE

Immunity to diphtheria and tetanus, defined as negative (susceptible) when the antitoxin level was < 0.01 IU/mL, positive (immune) when it was > or = 0.1 IU/mL, and low positive (partially immune) when it was in the range 0.01-< 0.1 IU/mL.

RESULTS

About 99% of children aged 5-9 years had diphtheria and tetanus antitoxin levels > or = 0.01 IU/mL (immune or partially immune). Antitoxin levels declined with age and generally more markedly for diphtheria than tetanus. For subjects aged 50 years and over, less than 60% were immune or partially immune to diphtheria and less than 75% to tetanus. Men and women had similar diphtheria antitoxin levels, while women had lower levels of tetanus antitoxin compared with men of the same age, with the difference being most marked in the age group > or = 70 years (37% v 60%; P < 0.001).

CONCLUSIONS

Immunity in children appears to be good, but adults, especially older people, may not be adequately protected. Recent changes to the Australian Standard Vaccination Schedule should improve immunity in cohorts now aged < 50 years. However, additional efforts are required to protect those over 50 years (especially travellers), who are most susceptible.

Determination of tetanus antibodies by a double-antigen enzyme-linked immunosorbent assay in individuals of various age groups

In this study, tetanus immunity was determined in 549 randomly chosen individuals of various age groups in Ankara, Turkey. Antibody levels in sera of the individuals were measured using a double-antigen enzyme-linked immunosorbent assay. Overall, 66.5% (95%CI, 62.4-70.4) of the population studied was found to have basic protection (>or=0.01 IU/ml) against tetanus. Protective levels of tetanus antibodies declined progressively with age. The rate of protection in children and adolescents (aged<20 years) exceeded 90%, while only 16.3% (95%CI, 8.9-26.2) of those over 60 years of age were protected. Females over 60 years of age were less immune than males of the same age group (p=0.034). Although the rates of protection in children and adolescents are regarded as satisfactory, the rates among adults are low. Preventive measures against tetanus should therefore focus on scheduled booster immunization for adults as well as children.

Tetanus seroprevalence among farmers: a preliminary study

BACKGROUND

Farmers are at increased risk of contracting tetanus. However, no difference in immunity to tetanus has been reported between rural and urban dwellers in large epidemiological studies. We hypothesized that tetanus antibody concentrations would be lower in farmers than in nonfarmers within the rural population.

METHODS

We recruited 102 adult subjects attending an agribusiness trade show who identified themselves as farmers in Wisconsin. The nonfarmer group (n = 120) was composed of adults attending the agribusiness show who were not engaged in farming or were participating in another research study. Concentrations of antibody to tetanus toxin (antiTT) in sera were measured by an enzyme-linked immunosorbent assay (IBL, Hamburg). AntiTT levels of >0.15 IU/mL were considered protective.

RESULTS

The antiTT concentrations for the farmer population (median = 2.74 IU/mL) were much higher than those for the nonfarmer group (median = 1.82 IU/mL) (P<.008). As in other studies, being male, being younger, and having a history of military service were positively correlated with protective antiTT concentrations. However, only farming, age, and the farming-sex interaction term were significantly associated with antiTT concentrations in the multiple-regression model.

CONCLUSIONS

The farmers we studied had high antiTT concentrations and a high tetanus seroprevalence rate. Occupation may be an important consideration in the development of immunization policies. A broader seroepidemiological study of farmers must be undertaken before any such considerations can be made.

Effect of transcutaneous immunization with co-administered antigen and cholera toxin on systemic and mucosal antibody responses in sheep

Direct application of antigens to skin together with an adjuvant, a procedure called transcutaneous immunization (TCI), can induce systemic immune responses in mice, humans, cats and dogs. In previous studies we found that cholera toxin (CT) applied topically on unbroken skin induces systemic antibody and lymphocyte proliferative responses in sheep. The current study examined whether concurrent administration of CT and tetanus toxoid (TT) delivered transcutaneously could induce specific antibody responses to both antigens in sheep. Antibodies to both TT and CT were induced by TCI although antibody titres in serum to TT were higher in sheep receiving TT plus alum by intramuscular injection (n=5) than TT plus CT by TCI (n=5). The ratio of IgG1/IgG2 antibody to TT in serum was near unity, and the route of immunization, TCI versus injection, did not influence this ratio. In contrast, the ratio of IgG1/IgG2 antibody differed significantly between the two antigens, TT and CT, delivered by TCI, with a higher proportion of IgG1 antibody in serum to CT than TT. Antibody to TT was detected in lung washes from TCI and injection groups, with IgG1 predominating over IgG2 in both groups. IgA antibodies to CT and TT were detected in sera of CT and TT-immunized groups respectively but in lung washes IgA antibody to TT was detected only in the injection group. Results show that TCI induced systemic antibody responses to CT and the co-administered antigen TT, whereas no evidence was obtained for mucosal IgA responses following TCI.

Immunity to poliomyelitis in The Netherlands

Despite a vaccination coverage rate of 97%, several poliomyelitis outbreaks occurred in the Netherlands during the last three decades, all among sociogeographically clustered, unvaccinated persons. Therefore, to eradicate polio, insight into poliomyelitis immunity is particularly useful. In 1995-1996, the authors conducted a population-based study and determined neutralizing antibodies against poliovirus types 1, 2, and 3 in 9,274 sera from the general population and from religious groups rejecting vaccination. In the general population, the antibody prevalence (>/=1:8) was 96.6% (95% confidence interval (CI): 95.9, 97.2), 93.4% (95% CI: 92.3, 94.5), and 89.7% (95% CI: 88.3, 91.0) for poliovirus types 1, 2, and 3, respectively. Antibodies persisted for long periods in persons with natural immunity as well as in persons whose immunity was induced by inactivated polio vaccine. In Orthodox Reformed persons, the antibody prevalence of poliovirus types 1, 2, and 3 was 65.0% (95% CI: 57.2, 72.9), 59.0% (95% CI: 40.1, 77.9), and 68.7% (95% CI: 65.2, 72.2), respectively. The recent outbreaks clearly affected the seroprevalence profiles of Orthodox Reformed groups but not the general population. At present, there is an insufficient social and political basis for mandatory vaccination; therefore, global eradication of poliovirus seems to be the only way to protect these Orthodox Reformed persons against future poliomyelitis outbreaks.