Tetanus immunity in individuals aged 50 years or older in Kashan, Iran

Tetanus can be only prevented by vaccination because immunity against this disease is rarely acquired, even by natural infections. To maintain long-term protective immunity against tetanus, booster immunization is essential for adolescents and adults. Most hospitalized cases and virtually all deaths occur in people over 60 years of age. The purpose of this study was to investigate the degree of protective tetanus immunity among 50 years of age and older people in Kashan city, Iran. This cross-sectional study carried out on 180 randomly individuals aged 50 years or older who were visiting a central laboratory for health examinations in 2008. Participants' serum levels of tetanus antitoxin were measured by enzyme linked immunosorbent assay. A standard questionnaire was used to collect demographic data and information about risk factors. The prevalence of protective tetanus immunity in various age groups was described and sociodemographic factors that potentially influenced the degree of tetanus immunity were analyzed. Overall, 180 persons were included. Of these, 72 (40%) had never received a toxoid booster, while 47 (26.1%) had received a booster at least once. Among all participants, 30 (16.7%) had protective tetanus antitoxin levels (≥ 0.11 IU/mL), and 34 (18.9%) had protective antitoxin levels without the need of an immediate booster ≥0.51 IU/mL. Among 86 participants aged >60 years, 6 (7%) had protective antitoxin levels ≥0.1-1 IU/mL, and 5(5.8%) had protective antitoxin levels ≥1 IU/mL. Male gender and prior receipt of toxoid booster(s) were associated with protective tetanus immunity. Tetanus antitoxin levels declined with age. It appears that most 50 years of age and older adults do not have protective levels of tetanus antitoxin because of inadequate vaccination coverage. There is a need to improve the immunity levels of this age group. It is recommended to vaccinate elderly people against tetanus.     

Immunity against diphtheria among children and adults in Izmir, Turkey

The aim of this study was to evaluate diphtheria immunity in a sample of the Turkish population having high childhood immunization coverage, including a booster dose of diphtheria toxoid at 12-15 years of age. A total of 599 persons aged 1-70 years were selected with cluster sampling. The information on socio-demographic characteristics, vaccination status and diphtheria history was gathered for each participant. Diphtheria antitoxin levels were measured qualitatively by using micro-enzyme immune assay. Of studied population, 72.3% had fully protective antitoxin levels (≥0.1 IU/ml). The rate of protection was 92.5% in the children aged 0-2 years, 93.2% in the primary school children aged 7-9 years, and 86.0% in the adolescents aged 15-19 years. After 20 years of age, diphtheria protection rates showed a significant age-related decrease, reaching minimum in the 30-39 age group, in which 47.3% of these subjects had fully protective antitoxin levels. The diphtheria antitoxin geometric mean titer (GMT) was highest in the 0-2 year age group (1.18 IU/ml). In the adolescents aged 15-19 years, diphtheria antitoxin GMT was 0.71 IU/ml. Then, geometric mean titer decreased with increasing age, and reached the minimum level in the 40-59 years age group (0.18 IU/ml). The protection rate among females was significantly lower than males (67.1% vs. 80.9%). The difference was apparent in the 20-29 and the 30-39 years age group: 80% of the males and 46.2% of the females in the 20-29 years age group, and 60% of males and 44.1% of females in the 30-39 years age group were fully protected against diphtheria (p < 0.0001). These results suggest that in Izmir, Turkey, full serological protection against diphtheria is only detectable in <50% of the young adult population, even though childhood immunization coverage is relatively high. Potentially, there is still risk of diphtheria outbreaks among the adults in our country. Therefore, a revaccination of adults with reduced doses of diphtheria toxoid should be considered to sustain diphtheria immunity.     

Immunogenicity of a combined diphtheria-tetanus-acellular pertussis vaccine in adults

Two clinical studies were undertaken to evaluate the immunogenicity of an adult-type dTpa booster vaccine (Boostrix by GlaxoSmithKline Biologicals). Blood samples taken prior to vaccination showed that 24.4 and 13.0% of subjects were seronegative for diphtheria and tetanus antibodies, respectively. Moreover, about one-third of the vaccinees had no detectable levels of antibodies to pertussis toxoid (PT) or pertactin (PRN). One month post-vaccination, more than 93% of all individuals, regardless of age or type of vaccine received, had seroprotective antibody levels for diphtheria and tetanus (> or = 0.1IU/ml). In those individuals vaccinated with the adult-type dTpa vaccine (Boostrix), more than 98% were found to be seropositive for antibodies to all three pertussis antigens (PT, filamentous haemogluttin (FHA), and PRN). These data suggest that immunity to diphtheria, tetanus and pertussis (DTP) in adults wanes and that booster vaccination with an adult-type combined dTpa vaccine would boost the serological response to diphtheria antitoxin, tetanus antitoxin and antibodies to Bordetella pertussis PT, FHA and PRN.     

Antitoxins for diphtheria and tetanus decline more slowly after vaccination with DTwP than with DTaP: A study in a Chinese population

Objectives

DTP vaccines are used for the prevention of pertussis, diphtheria and tetanus. In 2007, in Gaobeidian city, China, the DTwP vaccine was replaced with DTaP. This study described the diphtheria and tetanus sero-epidemiology in subjects vaccinated solely with DTwP or DTaP.

Methods

Blood samples were obtained between October 2012 and June 2013 from 587 healthy subjects aged 2–17 years. Serum IgG antibodies against diphtheria and tetanus were determined using ELISA. Interrupted time series analyses examined the changes in antitoxin levels over time and analyzed the alterations in diphtheria and tetanus antitoxin levels after the vaccine switch.

Results

Mean concentrations of diphtheria antitoxin and tetanus antitoxin were 0.074 IU/ml (95% CI 0.065–0.084) and 0.063 IU/ml (95% CI 0.053–0.076). The protection rates (antitoxins >0.01 IU/ml) for diphtheria and tetanus were 88.25% and 82.11%. Mean antitoxin levels for both diphtheria and tetanus decreased with increasing age, but this decrease was much slower for DTwP than DTaP.

Conclusions

Although the observed protection rates for diphtheria and tetanus were sufficient to prevent an outbreak at present, the means levels of diphtheria and tetanus antitoxins decreased with increasing age; therefore, booster vaccinations at 7 and 12 years of age would be strengthened in Gaobeidian city, China.     

Immunogenicity of a low-dose diphtheria,tetanus and acellular pertussis combination vaccine with either inactivated or oral polio vaccine compared to standard-dose diphtheria,tetanus, acellular pertussis when used as a pre-school booster in UK children: A 5-year follow-up of a randomised controlled study

This serological follow up study assessed the kinetics of antibody response in children who previously participated in a single centre, open-label, randomised controlled trial of low-dose compared to standard-dose diphtheria booster preschool vaccinations in the United Kingdom (UK). Children had previously been randomised to receive one of three combination vaccines: either a combined adsorbed tetanus, low-dose diphtheria, 5-component acellular pertussis and inactivated polio vaccine (IPV) (Tdap–IPV, Repevax^®; Sanofi Pasteur MSD); a combined adsorbed tetanus, low-dose diphtheria and 5-component acellular pertussis vaccine (Tdap, Covaxis^®; Sanofi Pasteur MSD) given concomitantly with oral polio vaccine (OPV); or a combined adsorbed standard-dose diphtheria, tetanus, 2-component acellular pertussis and IPV (DTap–IPV, Tetravac^®; Sanofi Pasteur MSD). Blood samples for the follow-up study were taken at 1, 3 and 5 years after participation in the original trial (median, 5.07 years of age at year 1), and antibody persistence to each vaccine antigen measured against defined serological thresholds of protection.All participants had evidence of immunity to diphtheria with antitoxin concentrations greater than 0.01 IU/mL five years after booster vaccination and 75%, 67% and 79% of children who received Tdap–IPV, Tdap + OPV and DTap–IPV, respectively, had protective antitoxin levels greater than 0.1 IU/mL. Long lasting protective immune responses to tetanus and polio antigens were also observed in all groups, though polio responses were lower in the sera of those who received OPV.Low-dose diphtheria vaccines provided comparable protection to the standard-dose vaccine and are suitable for use for pre-school booster vaccination.     

Immunity to tetanus and diphtheria in the UK in 2009

Introduction

This study aimed to estimate the immunity of the UK population to tetanus and diphtheria, including the potential impact of new glycoconjugatate vaccines, and the addition of diphtheria to the school leaver booster in 1994.

Methods

Residual sera (n = 2697) collected in England in 2009/10 were selected from 18 age groups and tested for tetanus and diphtheria antibody. Results were standardised by testing a panel of sera (n = 150) to enable comparison with a previously (1996) published serosurvey. Data were then standardised to the UK population.

Results

In 2009, 83% of the UK population were protected (≥0.1 IU/mL) against tetanus compared to 76% in 1996 (p = 0.079), and 75% had at least basic protection against diphtheria (≥0.01 IU/mL) in 2009 compared to 60% in 1996 (p < 0.001). Higher antibody levels were observed in those aged 1–3 years in 2009 compared to 1996 for both tetanus and diphtheria. Higher diphtheria immunity was observed in those aged 16–34 years in 2009 compared to 1996 (geometric mean concentration [GMC] 0.15 IU/mL vs. 0.03 IU/mL, p < 0.001). Age groups with the largest proportion of susceptible individuals to both tetanus and diphtheria in 2009 were <1 year old (>29% susceptible), 45–69 years (>20% susceptible) and 70+ years (>32% susceptible). Low immunity was observed in those aged 10–11 years (>19% susceptible), between the scheduled preschool and school leaver booster administration.

Discussion

The current schedule appears to induce protective levels; increases in the proportions protected/GMCs were observed for the ages receiving vaccinations according to UK policy. Glycoconjugate vaccines appear to have increased immunity, in particular for diphtheria, in preschool age groups. Diphtheria immunity in teenagers and young adults has increased as a result of the addition of diphtheria to the school leaver booster. However, currently older adults remain susceptible, without any further opportunities for immunisations planned according to the present schedule.     

Immune response to a diphtheria and tetanus toxoid administration in a three-dose diphtheria tetanus whole-cell pertussis/enhanced inactivated poliovirus vaccination schedule: a 7-year follow up

The immune response to diphtheria and tetanus toxoid components of a combined diphtheria tetanus whole-cell pertussis/enhanced inactivated poliovirus (DTwP/eIPV) vaccine, administered in a three-dose schedule to infants at 2, 3 and 10 months of age and followed by a booster at the age of 8 years, was compared with the immune profile of a group of children at the same ages given the customary DTwP vaccine schedule at 2, 4, 6, and 12 months of age and a booster at the age of 8. Diphtheria- and tetanus-antitoxin titers were measured in parallel enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA). After the reinforcing dose given at 10 months of age, diphtheria antitoxin concentrations of 0.01 IU/ml were found in 100% of infants in the study group, 91.7% of whom reached a titer of 0.1 IU/ml and a geometric mean titer (GMT) of 0.40 and 0.93 IU/ml in ELISA and RIA, respectively. At 3 and 6 years of age, diphtheria antitoxin values of 0.01 IU/ml were detected in 100 and 94% of children with GMT of 0.043 and 0.024 IU/ml, respectively. Seropositivity and GMT values indicative of protection were measured by both ELISA and RIA after the booster at the age of 8 years. Similar results were found in the control group, although the GMT tended to be higher. A good correlation between results obtained by ELISA vs. RIA was evident throughout. Priming at 2 and 3 months with diphtheria and tetanus antitoxin, as a component of a DTwP program, and reinforcing 6 months later induced an immune response indicative of protection against the diseases, which persisted up to the age of the booster recommended at school entry.     

Immunity to diphtheria in Izmir, Turkey

In order to assess immunity to diphtheria in Izmir, Turkey, a total of 743 persons 1–70 years of age were selected with cluster sampling. The information on socio-demographic characteristics, vaccination status and diphtheria history was gathered for each participant. Diphtheria antitoxin levels were measured qualitatively by using micro-enzyme immune assay. Of studied population, 79.1% had fully protective antitoxin levels ( 0.1 IU/ml). Diphtheria protection rates showed a gradual age-related decrease, reaching minimum in the 30–44 age group, in which 40.2% of these subjects had antibody titre below the full protective level. The diphtheria antitoxin geometric mean titer was highest in the 5–9 year age group (1.05 IU/ml). Then, geometric mean titer decreased with increasing age, and reached the minimum level in the 30–44 age group (0.19 IU/ml). These results suggest that in Izmir, Turkey, full serological protection against diphtheria is only detectable in 60% of the adult population. The enhancement of diphtheria immunity by booster vaccinations in adolescents and adults should be considered in Turkey.     

Attenuated immune response to tetanus toxoid in young healthy men protected against tetanus

Tetanus booster is a routine procedure of tetanus prevention in populations with high risk of injury, independent of the levels of protection. But the immune response in already protected individuals is not well studied. We describe the kinetics of booster response in individuals by measuring tetanus antitoxin levels by indirect ELISA. A 6-month follow up was performed on 60 boosted individuals tested before, 1 week, 1, 2, 3 and 6 months after the booster. High initial protection (mean titer 1.08 IU/ml) and less than 3-fold increase after 1 month were observed. After 1 month of stable antitoxin levels, the levels slowly decreased and reached a mean titer of 1.78 IU/ml after 6 months. Individuals with initial levels <1 IU/ml had booster response after the first month twice as high compared to those with initial level >or=1 IU/ml. However, in both groups, the decline from 1 to 6 months was about 2-fold. Individuals already protected against tetanus exhibited an attenuated, short-lasting booster response to tetanus toxoid. This was more pronounced in individuals with pre-booster levels >or=1 IU/ml, who did not improve immune protection after the booster.     

临沂市健康人群白喉和破伤风抗体水平调查

目的为有计划地进行人群抗体水平监测,了解人群免疫状况,为制定免疫对策、评价免疫效果提供依据。方法采用分层随机抽样的方法,2001、2003、2004年调查了临沂市10个县(区)0~39岁847人的白喉和破伤风抗体水平。结果白喉和破伤风抗体总阳性率分别为77.80%和74.03%,阳性率均是0~4岁组最高,20~39岁组最低;山区县低于平原县和市区。白喉和破伤风抗体几何平均浓度分别为0.0997U/ml和0.0674U/ml,均是8~10岁组最高,20~39岁组最低。结论临沂市白喉和破伤风疫苗基础免疫的效果可靠,但随着年龄的增长,免疫力衰退而重新成为易感者,故应及时对成人加强百日咳、白喉的免疫,并在新生儿破伤风高危县区对育龄期妇女开展破伤风疫苗免疫。     

临沂市健康人群白喉和破伤风抗体水平调查

目的 为有计划地进行人群抗体水平监测,了解人群免疫状况,为制定免疫对策、评价免疫效果提供依据。方法 采用分层随机抽样的方法,2001、2003、2004年调查了临沂市10个县（区）0-39岁847人的白喉和破伤风抗体水平。结果 白喉和破伤风抗体总阳性率分别为77.80%和74.03%,阳性率均是0-4岁组最高,20-39岁组最低;山区县低于平原县和市区。白喉和破伤风抗体几何平均浓度分别为0.0997U/ml和0.0674U/ml,均是8-10岁组最高,20-39岁组最低。结论 临沂市白喉和破伤风疫苗基础免疫的效果可靠,但随着年龄的增长,免疫力衰退而重新成为易感者,故应及时对成人加强百日咳、白喉的免疫,并在新生儿破伤风高危县区对育龄期妇女开展破伤风疫苗免疫。     

2008年邻水县健康人群抗体水平监测结果分析

目的了解2008年广安市邻水县健康人群麻疹、白喉、百日咳、破伤风和乙型肝炎免疫水平状况,及时为免疫决策提供科学依据。方法在邻水县随机抽取7个年龄组304名健康人群作为监测对象,进行麻疹IgG抗体、白喉和破伤风抗毒素、乙肝表面抗体和百日咳凝集抗体水平检测。结果麻疹IgG抗体阳性（〉200mIU/ml）有289人,阳性率为95.07%;白喉抗毒素达到保护水平的有290人,阳性率为95.39%,抗毒素平均值为0.28IU/ml;百日咳抗体阳性（≥1∶20）有295人,阳性率为97.04%,保护性抗体阳性率为66.78%;破伤风抗毒素达到保护水平的有247人,阳性率为81.25%;乙肝表面抗体阳性的有164人,阳性率为53.95%;结论广安市邻水县健康人群麻疹、白喉和百日咳抗体达到标准水平;破伤风抗毒素和乙肝表面抗体未达到标准水平,需加强免疫接种工作,提高人群免疫水平。     

Immunity to diphtheria in Siena.

The aim of this study, carried out in 1993, was to evaluate diphtheria immunity in Siena. Diphtheria antitoxin levels were measured by means of the immunoenzymatic test (ELISA) in serum samples of 602 apparently healthy subjects (239 males and 363 females) of all ages residing in Siena. According to widely used criteria, 6% of the total population were susceptible to diphtheria (antibody levels < 0.01 IU/ml), 71% had basic protection (0.01-0.09 IU/ml) and 23% were fully protected (> or = 0.1 IU/ml). The results suggested that a high proportion of young population had a protective level of immunity against diphtheria, that susceptibility increased with age and a smaller proportion of males (2.9%) than females (8.3%) were unprotected; this difference was statistically significant. Our results suggest that it may be useful to revaccinate adults with low levels of diphtheria toxoid so that the percentage that remains unprotected does not put the community at risk of an outbreak of diphtheria.     

The prevalence of diphtheria immunity in healthy population in Poland

The degree of seroprotection against diphtheria in Poland was evaluated by determination of IgG antibodies to Corymebacterium diphtheriae toxin (IgG-DTAb). The study population consisted of 4,829 healthy subjects aged from 1 day to 85 years from 7 regions of Poland. Serum samples collected between 1996 and 1998 were assayed for IgG-DTAb antibodies using a toxoid enzyme immunoassay. Neutralization of toxin in Vero cells was performed as a reference method with the WHO standard for human diphtheria antitoxin. The study revealed a lack of seroprotection (IgG-DTAb < 0.1 IU/ml) in 23% of individuals, basic seroprotection (0.1-1.0 IU/ml) in 64%, and effective seroprotection (> 1.0 IU/ml) in 13%. The non-protected group consisted of non-vaccinated children below 2 months of age (10%), individuals between 2 months and 18 years old (20%) and greater than 19 years old (70%). Of the adults, 32% were seronegative, 63% had basic seroprotection and only 5% were fully protected; 43% of adults between 30 and 64 years, who had not been vaccinated at least during the previous 10 years were not protected against diphtheria. The geometric mean titre (GMT) of IgG-DTAb was 0.25 IU/ml in the total population. Age-related GMTs differed significantly from each other and were higher (0.44 IU/ml) in individuals from 2 months to 18 years old, compared with 014 IU/ml and 0.17 lU/ml in children under 2 months and adults, respectively. No significant difference was found in the GMTs of men and women in all age groups. We conclude that the currently used vaccination programme in Poland is highly effective and assures protection against diphtheria in the majority of the population in the 10-year period following the last booster. However, a significant proportion of adults between 30 and 64 years lack protection and this indicates a need for booster immunization for this group.     

Immunity to diphtheria and tetanus in inner-city women of childbearing age.

This study was conducted to determine immunity to diphtheria and tetanus in 232 inner-city women experiencing a recent birth. Forty-three (18.5 percent) of the women had levels of diphtheria antitoxin below the protective level (less than 0.01 unit/ml), whereas only 10 (4.3 percent) had insufficient levels of tetanus antitoxin. The percent of women susceptible increased with age, with 33 percent and 25 percent of women over the age of 30 years susceptible to diphtheria and tetanus, respectively.     

Safety and immunogenicity of single dose of tetanus–diphtheria (Td) vaccine among non/partially immune children against diphtheria and/or tetanus,Hyderabad, India, 2007

In Hyderabad, India, diphtheria is common among children aged 5–19 years. On account of low coverage of diphtheria vaccine boosters recommended under the universal immunization programme, a large proportion of children were susceptible/partially immune against diphtheria and/or tetanus. We evaluated immunogenicity and safety of single dose of indigenously developed tetanus–diphtheria (Td) vaccine (diphtheria–toxoid ≤5 Lf) among 483 school children from Hyderabad aged 7–17 years and susceptible/partially immune against diphtheria and/or tetanus. Serological testing 6 weeks after vaccination indicated that vaccine was highly immunogenic with >96% sero-protected against both antigens. The immune response observed indicated a booster response to previously acquired immunity. Administration of additional dose of Td vaccine to the older school children and replacing the tetanus toxoid vaccine with Td in the school health programme would considerably reduce diphtheria burden in Hyderabad.     

Immunity to diphtheria in the 3-19 year age group in Italy.

In Italy, immunization with diphtheria toxoid has been compulsory for all newborns since 1939. The last two clinical cases of diphtheria were reported in 1987. During the period 1987-1989, immunity against diphtheria was assessed by neutralization test in a random sample of 1740 healthy subjects 3-19 years old, from five geographical areas of Italy. Of the total population, 76.5% showed antibody levels considered to be protective (greater than or equal to 0.1 IU ml-1), 17.2% had a relative degree of protection (0.01-0.09 IU ml-1), and 6.3% lacked immunity (less than 0.01 IU ml-1). The percentage of unprotected subjects increased from 6.1% in the age group of 3-5 years to 11.4% in the age group of 18-19 years (p less than 0.01). A smaller proportion of males (5.3%) than of females (7.2%) was unprotected, but this difference was not statistically significant. Subjects residing in the south and the islands were more likely to be unprotected than those residing in the north (7.4 versus 4.1%, p less than 0.01). No association was found between lack of protective antibodies and family size (odds ratio 1.35, confidence interval 95% = 0.77-2.36). However, paternal education of less than 12 years was associated with a higher prevalence of non-responders. In order to maintain a high degree of immunity in the adult population, a routine adult booster dose of diphtheria toxoid is advisable.     

Short-term booster effect of diphtheria toxoid in initially long-term protected individuals

The main objective of this study was to investigate the booster antibody response in individuals with initially high levels of diphtheria antitoxin. Sixty individuals eligible for the routine booster by the age of 18 years each received a single dose of 5 Lf of diphtheria toxoid in diphtheria-tetanus vaccine. A double antigen ELISA was used for the assessment of the antibody levels. Chaotropic disruption in paired ELISA was used to test antibody avidity. The ratio between initial and maximum antibody concentrations after 1 month was >10 times higher and after 6 months still four times higher in those with initial antibody levels <1 IU/ml. In individuals with initial antibody levels >/=1 IU/ml a two-fold decrease was observed after 6 months compared to the initial levels. Thus, vaccination of individuals with initial long-term protection against diphtheria (antibody levels >/=1 IU/ml) is unnecessary and should be avoided.     

Tetanus and diphtheria antitoxin levels following a hospital-based adult immunization program.

A hospital-based program to immunize adults against tetanus unless specific contraindications to immunization are present has been in effect at Parkland Memorial Hospital since 1959. Adsorbed tetanus toxoid was used from 1959 to 1970, and was replaced at that time by adult type adsorbed combined tetanus/diphtheria toxoid. In the present survey, the titers of diphtheria and tetanus antitoxins were determined in sera from 97 adults admitted to the Medical Service. Titers of diphtheria antitoxin less than 0.0125 units per ml were found in only seven patients and less than 0.0125 units per ml of tetanus antitoxin in only 17 patients. This high prevalence of immunity especially to tetanus appears to reflect our practice of routine immunization of adults. Although the recommended frequency of tetanus boosters has recently been reduced for adults who have completed a full primary immunization series, susceptibility to diphtheria or tetanus or both is not uncommon among adults in the US. Unless contraindications are present, we therefore urge routine immunization of all adults seeking medical care and of all hospital personnel as a means of diminishing the risk of diphtheria and tetanus in those adult populations with a significant incidence of susceptibility to these diseases.     

河南省健康人群白喉和破伤风抗体水平调查

目的为有计划地进行人群抗体水平监测,了解人群免疫状况,为制定免疫对策、评价免疫效果提供依据。方法采用分层整群随机抽样的方法,1998~2002年调查了河南省21个县(区、市)2~39岁3 510人的白喉和破伤风抗体水平。结果白喉和破伤风抗体总阳性率分别为80.5%和77.9%,阳性率均是2~3岁最高,25~39岁最低;山区县低于平原县和市区。白喉和破伤风抗体几何平均浓度分别为0.101IU/ml和0.073IU/ml,均是8~9岁最高,25~39岁最低。结论河南省白喉和破伤风疫苗基础免疫的效果可靠,但随着年龄的增长,免疫力衰退而重新成为易感者,故应及时对成人加强白喉疫苗的免疫,并在新生儿破伤风高危县对育龄期妇女开展破伤风疫苗免疫。