Protection against tetanus

Tetanus vaccination status in construction workers: results from an institutional surveillance campaign

Background:

Since 1963 Italian law (Law 292/1963, Legislative Decree n.81/2008), defines Tetanus Vaccination (TeV) as mandatory for defined occupational categories, including Construction Workers (CWs).

Materials and Methods:

An institutional survey on of CWs was performed in the Autonomous Province of Trento (Oct. 2016 - Apr. 2017). Vaccination booklets/certificate were retrieved recalling: TeV status (1), and TeV settings (2), i.e. basal schedule; year of last shot, healthcare providers who performed TeV, and TeV formulate(s).

Results:

Data about 205 CWs were collected (mean age 40.6±10.3 years; 78.0% <50 year-old, 71.7% born in Italy). Overall, 38.5% of CW had received last vaccination shot >10 years before the survey (mean: 8.8 ± 8.2 years). The majority of boosters had been administered by Vaccination Services of the Local Health Unit (47.3%), followed by Occupational Physicians (20.0%) and General Practitioners (11.2%). In 85.9% of CWs, a monovalent formulation was used. Combined TeV were mainly reported in CW who had received last vaccination shot in Vaccination Services (96.2%; p<0.001).

Conclusions:

TeV coverage rates in CWs are insufficient, and vaccination shots are frequently performed with inappropriate, monovalent formulates. As only professionals from Vaccination Services systematically employ combined vaccines and particularly Tdap, our results not only stress the opportunity for promoting TeV among CWs, but also the importance of improving reception of up to date official recommendations in Occupational Physicians, General Practitioner and professionals of Emergency Departments. (www.actabiomedica.it)

Tetanus-diphtheria vaccination in adults: the long-term persistence of antibodies is not dependent on polyclonal B-cell activation and the defective response to diphtheria toxoid re-vaccination is associated to HLADRB1∗01

Cellular and humoral immune responses to tetanus-diphtheria vaccine (Td) were assessed in human leukocyte antigen (HLA)-typed Italian military personnel who received multiple concomitant vaccines. Td-specific antibodies and T-lymphocytes were measured in individuals with one (group-1) and more than one (group-2) Td boosters. A third group (group-3), who received several vaccines, but not Td, was studied to verify the hypothesis of the polyclonal B-cell activation as mechanism for antibody persistence. The antibody response to Td toxoids was higher in group-1, who showed lower baseline antibody levels, than in group-2 subjects. The antibody response to tetanus was higher than to diphtheria toxoid in both groups. No correlation between antibody and cellular response, and no interference in the response to Td by co-administration of different vaccines were observed. HLA-DRB1∗01 allele was detected at significant higher frequency in subjects unable to double the baseline anti-diphtheria antibody levels after the vaccination. Anti-tetanus and diphtheria antibodies half-lives were assessed and the long-lasting persistence above the threshold for protection (0.1 IU/ml) was estimated in over 65 and 20 years, respectively. No significant increase of anti-diphtheria antibodies was observed in consequence of polyclonal B-cell activation. This study emphasizes the duration of Td vaccination-induced seroprotection, suggesting that re-vaccination should probably be performed at intervals longer than 10 years. No reciprocal interference by concomitantly administered vaccines has been observed. HLA-DRB1∗01 allele was significantly associated with anti-diphtheria defective response. Finally, this study does not confirm that anti-diphtheria antibody levels are maintained by polyclonal B-cell activation. Clinical trial registry: The study was registered with NCT01807780.

Not to be Forgotten: Tetanus

We describe a patient presenting with altered mental state, generalised stiffening of the body and limbs as a result of acute generalised tetanus. Discussion of the clinical manifestations, diagnosis, initial management in the emergency department and complications is put forth.

Knowledge, attitudes, beliefs and practices of construction workers towards tetanus vaccine in Northern Italy

Construction workers (CWs) are both more exposed to tetanus and at higher risk to be inadequately immunized. Our aim was to evaluate tetanus immunization status and knowledge/attitudes towards tetanus vaccination in CWs in Italy. In this field report, the immunization status of 554 unskilled CWs (i.e. labourers). Immunization status was assessed recalling immunization booklets/certificates. Attitudes and knowledge were collected through a standardized questionnaire. In 240/554 CWs, immunization status was inadequate/not documented: in 184 subjects (33.2%), the last vaccination shot was older than 10 years, whereas basal immunization was incomplete in 20 cases, more frequently in foreign-born people (FBP) than in Italian born (IBP) (OR=7.116). In 198 cases (35.7%), an Occupational Physician (OPh) performed last booster, usually with monovalent (T, n=173) vaccine. The main reason for inadequate immunization was having forgotten the periodic booster (148/554; 26.7%), whereas 42 subjects (7.6%) deliberately avoided tetanus vaccine because of personal/religious beliefs, more frequently in FBP than in IBP (OR=3.182). In summary, the prevalence of inadequate immunization status was relatively high (43.4%): the high prevalence of "forgotten boosters" enlightens the key role of OPh in recalling and promoting vaccination policies. Moreover, the inappropriate use of Td vaccine points out the opportunity for educational campaigns in OPh.

Tetanus in Italy 2001-2010: a continuing threat in older adults

Despite being a completely preventable disease, tetanus cases continue to occur in Italy and notification and hospitalization rates have been reported to be higher with respect to European and other industrialized countries. We examined statutory notification, hospitalization, mortality and seroprevalence data to describe tetanus epidemiology in Italy from 2001 to 2010. A total of 594 tetanus cases were notified, with an average annual incidence of 1.0/1,000,000 population. Most cases were unvaccinated or incompletely vaccinated. Eighty percent of cases occurred in subjects aged >64 years and a higher proportion of females with respect to males were reported in this age group. The annual number of hospital admissions was 1.4-1.7 times greater than the number of notifications in the same year. The mean annual number of reported deaths was 21. Seroprevalence data show progressively higher susceptibility levels with increasing age. Over 50% of persons aged 45-64 years and over two thirds of subjects ≥65 years had tetanus antibody levels <0.01 IU/ml. Results show that tetanus is a continuing problem in Italy and, as in other countries, most cases occur in older adults, especially elderly women. The observed differences in notification and hospitalization rates suggest underreporting by physicians. In recent years, Italy has accounted for most cases reported annually in the European Union (EU) but different case definitions are used. In Italy, a confirmed case is one that meets the clinical case definition while the EU case definition classifies confirmed cases as those with laboratory confirmation of disease. The incidence of clinical tetanus in Italy is ten-fold higher than in other industrialized countries, like Australia and Canada, likely due to higher susceptibility levels in Italy. In view of the low prevalence of tetanus antibodies in adults ≥45 years, strategies to improve vaccine uptake in this population group need to be implemented.

Serum antibodies to diphtheria-tetanus-pertussis vaccine components in Argentine children

The Argentine vaccination schedule against diphtheria, tetanus and pertussis (DTP) recommends three doses of DTP vaccine at 2, 4 and 6 months of age, two boosters at 18 months and 6 years, a booster dose of tetanus vaccine every 10 years and two doses during pregnancy. To evaluate the effect of this schedule, antibodies against pertussis toxin (PT) and filamentous hemagglutinin (FHA) and against tetanus and diphtheria toxoids were determined by ELISA in serum samples from children (1 month to 6 years) who received different doses of DPT vaccine: 0 dose (n = 50), 1 dose (n = 25), 2 doses (n = 25), 3 doses (n = 55), first and second booster (n = 25); 25 pregnant women and their offspring, and 45 adults. High antibody levels against PT (> 140 EU/ml) and FHA (> 80 EU/ml) were recorded in mothers and in the newborn. Antibody titers against PT increased with the number of doses given and decreased with time. Full protection against tetanus (titers > 0.1 IU/ml) was observed in the group of adults (0.37 IU/ml), in mothers (4.4 IU/ml) and their newborn offspring (5.5 IU/ml), and in children after receiving the second dose of DTP vaccine (1.86 IU/ml). The immune status for diphtheria was far lower, as most of the groups lacked adequate protection. After the third dose of DTP vaccine, only 78% of the children had antibody titers above the protective level (0.1 IU/ml). Since antibody levels considered to provide full protection were only achieved after the first booster dose of DTP vaccine, the primary three-dose schedule seems to be insufficient to confer adequate immunity in all vaccinees. Because of the high proportion of non-protected adults, a booster dose of Td vaccine should be considered for this group.

Structure and protective capacity of tetanus and diphtheria antibodies produced during human pregnancy and transferred to new-born

PROBLEM

The structure and protective activity of antibodies against tetanus (anti-T) and diphtheria (anti-D), produced during human pregnancy and transferred to new-born, was studied.

METHOD

Antibody levels were measured by ELISA in non-pregnant women (control group), primiparae, and multiparae, and in their children. The proportion of symmetric and asymmetric IgG molecules was determined and their respective protective capacity evaluated.

RESULTS

The quantity of asymmetric anti-T and anti-D antibodies in mothers at the time of delivery was roughly four- and three-fold that of the control group, respectively, dropping significantly 1 month later. A similar proportion of these antibodies was observed in the new-born. The lower neutralizing capacity of asymmetric molecules was demonstrated in vivo.

CONCLUSION

Results show that during pregnancy there is a modulation of the immune response with an increase in the production of asymmetric molecules of lower protective capacity.