Diphtheria antitoxin levels in the Netherlands: a population-based study

The evaluation of anti-diphtheria toxoid antibodies in healthy population in Kon Tum, Vietnam: a population-based study

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The risk of diphtheria remains high in Kon Tum given the low seroprevalence.

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One third of community in Kon Tum have no protective antibodies to diphtheria.

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The antibodies from previous childhood vaccination gradually wane over time.

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A booster dose (5-7 years) is recommended for adolescents and adults in Vietnam.

Background

Despite diphtheria immunization are to apply an effective primary immunization in childhood and to maintain immunity throughout life. Cases of diphtheria have been reported in Viet Nam in recent years. The aim of this study was to evaluate the seroprevalence of IgG antibodies to diphtheria toxoid among healthy person population in Kon Tum, Viet Nam.

Methods

Blood samples were obtained from 2225 healthy persons aged 2-98 years collected in 2019 and 2020. Samples were tested for diphtheria toxoid antibodies by commercial Anti-Diphtheria Toxoid IgG Enzyme-Linked Immunosorbent Assay (ELISA).

Results

An antibody level of <0.01 IU/mL (susceptibility) was found in 802 (36.0%) of the 2225 subjects, 136 (6.1%) had antibody levels of 0.01–0.099 IU/mL (basic protection), and 1287 (57.8%) had antibody levels ≥0.1 IU/mL (full protection). The full protection level increased significantly in persons aged above 60 years with antibody levels of 70.6%. No significant difference in seroprotection prevalence was found according to gender, ethnicity, residence, education and occupation. The results also demonstrated that people with vaccination against diphtheria during past 10 years were found to have a high immunity (83.8%) compared to 54.8% (OR: 4.7; 95%CI: 3.8-6.5) and 60.7% (OR: 3.8; 95%CI: 2.6-5.7) in persons with no and unknown vaccination (p <0.0001).

Conclusions

The level of anti-diphtheria toxoid antibodies among children and adults in Kon Tum was low. The high risk of diphtheria outbreaks may occur among individuals lacking basic immunity against diphtheria.

Diphtheria and tetanus seroepidemiology among children in Ukraine, 2017

BACKGROUND

The drastic decline of Ukraine's immunization coverage since 2009 led to concerns about potential resurgence diphtheria and tetanus, along with other vaccine-preventable diseases.

METHODS

To assess population immunity against diphtheria and tetanus, we tested specimens from the serosurvey conducted in 2017 among children born in 2006-2015, the birth cohorts targeted by the nationwide outbreak response immunization following a circulating vaccine-derived poliovirus type 1 outbreak in Zakarpattya province in 2015. We surveyed four regions of Ukraine, using cluster sampling in Zakarpattya, Sumy, and Odessa provinces and simple random sampling in Kyiv City. We tested serum specimens for IgG antibodies against diphtheria and tetanus, using microbead assays (MBA). We estimated seroprevalence and calculated 95% confidence intervals. We also obtained information on the immunization status of surveyed children.

RESULTS

Seroprevalence of ≥0.1 IU/mL diphtheria antibodies was <80% in all survey sites (50.0%-79.2%). Seroprevalence of ≥0.1 IU/mL tetanus antibodies was ≥80% in Sumy, Kyiv City, and Odessa (80.2%-89.1%) and 61.6% in Zakarpattya. Across the sites, the proportion of children vaccinated age-appropriately with diphtheria-tetanus-containing vaccines (DTCV) was 28.5%-57.4% among children born in 2006-2010 and 34.1%-54.3% among children born in 2011-2015. The proportion of recipients of <3 DTCV doses increased from 7.1%-16.7% among children born in 2006-2010 to 19.8%-38.6% among children born in 2011-2015, as did the proportion of recipients of zero DTCV doses (2.6%-8.8% versus 8.0%-14.0%, respectively).

CONCLUSIONS

Protection against diphtheria among children born in 2006-2015 was suboptimal (<80%), particularly in Zakarpattya. Protection against tetanus was adequate (≥80%) except in Zakarpattya. Diphtheria-tetanus immunization status was suboptimal across all sites. Catch-up vaccination of unvaccinated/under-vaccinated children and other efforts to increase immunization coverage would close these immunity gaps and prevent the resurgence of diphtheria and tetanus in Ukraine, particularly in Zakarpattya.

Seroprevalence of diphtheria toxoid IgG antibodies in the Malaysian population

Background

Despite high childhood immunization coverage, sporadic cases of diphtheria have been reported in Malaysia in recent years. This study aims to evaluate the seroprevalence of diphtheria among the Malaysian population.

Methods

A total of 3317 respondents age 2 years old to 60 years old were recruited in this study from August to November 2017. Enzyme-linked immunosorbent assay (ELISA) was used to measure the level of IgG antibody against the toxoid of C. diphtheriae in the blood samples of respondents. We classified respondent antibody levels based on WHO definition, as protective (≥0.1 IU/mL) and susceptible (< 0.1 IU/mL) to C. diphtheriae infection.

Results

Among the 3317 respondents, 57% were susceptible (38.1% of children and 65.4% of adults) and 43% (61.9% of children and 34.6% of adults) had protective antibody levels against diphtheria. The mean antibody level peaked among individuals aged 1–2 years old (0.59 IU/mL) and 6–7 years old (0.64 IU/mL) but generally decreased with age, falling below 0.1 IU/mL at around 4–6 years old and after age 20 years old. There was a significant association between age [Children: χ² = 43.22(df = 2),p < 0.001)], gender [Adults: χ² = 5.58(df = 1),p = 0.018] and ethnicity [Adults: χ² = 21.49(df = 5),p = 0.001] with diphtheria toxoid IgG antibody level.

Conclusions

About 57% of the Malaysian population have inadequate immunity against diphtheria infection. This is apparently due to waning immunity following childhood vaccination without repeated booster vaccination in adults. Children at age 5–6 years old are particularly vulnerable to diphtheria infection. The booster vaccination dose normally given at 7 years should be given earlier, and an additional booster dose is recommended for high-risk adults.

Does vaccination ensure protection? Assessing diphtheria and tetanus antibody levels in a population of healthy children: A cross-sectional study

Vaccination effectiveness is proven when the disease does not develop after a patient is exposed to the pathogen. In the case of rare diseases, vaccination effectiveness is assessed by monitoring specific antibody levels in the population. Such recurrent analyses allow the evaluation of vaccination programs. The primary schedule of diphtheria and tetanus vaccinations is similar in various countries, with differences mainly in the number and timing of booster doses. The aim of the study was to assess diphtheria and tetanus antibody concentrations in a population of healthy children.Diphtheria and tetanus antibody levels were analyzed in a group of 324 children aged 18 to 180 months. All children were vaccinated in accordance with the Polish vaccination schedule.Specific antibody concentrations greater than 0.1 IU/mL were considered protective against tetanus or diphtheria. Levels above 1.0 were considered to ensure long-term protection.Protective levels of diphtheria antibodies were found in 229 patients (70.46%), and of tetanus in 306 patients (94.15%). Statistically significant differences were found in tetanus antibody levels in different age groups. Mean concentrations and the percentage of children with high tetanus antibody titers increased with age. No similar correlation was found for diphtheria antibodies. High diphtheria antibody levels co-occurred in 72% of the children with high tetanus antibody levels; 95% of the children with low tetanus antibody levels had low levels of diphtheria antibodies.The percentage of children with protective diphtheria antibody levels is lower than that in the case of tetanus antibodies, both in Poland and abroad, but the high proportion of children without diphtheria protection in Poland is an exception. This is all the more puzzling when taking into account that Polish children are administered a total of 5 doses containing a high concentration of diphtheria toxoid, at intervals shorter than 5 years. The decrease in antibody titers occurring over time is a significant factor in vaccination program planning.Tetanus antibody concentrations were found to be high, but responses to the diphtheria and tetanus components were divergent. The percentage of children protected against diphtheria was significantly lower than protected against tetanus.

Long-Term Protection against Diphtheria in the Netherlands after 50 Years of Vaccination: Results from a Seroepidemiological Study

BACKGROUND AND AIMS

To evaluate the National Immunisation Programme (NIP) a population-based cross-sectional seroepidemiological study was performed in the Netherlands. We assessed diphtheria antitoxin levels in the general Dutch population and in low vaccination coverage (LVC) areas where a relatively high proportion of orthodox Protestants live who decline vaccination based on religious grounds. Results were compared with a nationwide seroepidemiological study performed 11 years earlier.

METHODS

In 2006/2007 a national serum bank was established. Blood samples were tested for diphtheria antitoxin IgG concentrations using a multiplex immunoassay for 6383 participants from the national sample (NS) and 1518 participants from LVC municipalities. A cut-off above 0.01 international units per ml (IU/ml) was used as minimum protective level.

RESULTS

In the NS 91% of the population had antibody levels above 0.01 IU/ml compared to 88% in the 1995/1996 serosurvey (p<0.05). On average, 82% (vs. 78% in the 1995/1996 serosurvey, p<0.05) of individuals from the NS born before introduction of diphtheria vaccination in the NIP and 46% (vs. 37% in the 1995/1996 serosurvey, p = 0.11) of orthodox Protestants living in LVC areas had antibody levels above 0.01 IU/ml. Linear regression analysis among fully immunized individuals (six vaccinations) without evidence of revaccination indicated a continuous decline in antibodies in both serosurveys, but geometric mean antibodies remained well above 0.01 IU/ml in all age groups.

CONCLUSIONS

The NIP provides long-term protection against diphtheria, although antibody levels decline after vaccination. As a result of natural waning immunity, a substantial proportion of individuals born before introduction of diphtheria vaccination in the NIP lack adequate levels of diphtheria antibodies. Susceptibility due to lack of vaccination is highest among strictly orthodox Protestants. The potential risk of spread of diphtheria within the geographically clustered orthodox Protestant community after introduction in the Netherlands has not disappeared, despite national long-term high vaccination coverage.

Immune Dysfunction in Children with CHARGE Syndrome: A Cross-Sectional Study

CHARGE syndrome is a variable, multiple congenital malformation syndrome. Patients with CHARGE syndrome have frequent infections that are presumed to be due to anatomical anomalies of the craniofacial region and upper airway, and cranial nerve problems resulting in swallowing difficulties and aspiration. The possible contribution of immunological abnormalities to these infections has not been systematically studied even though immune deficiencies have been described in patients with 22q11.2 deletion syndrome, a condition which shares remarkable clinical overlap with CHARGE syndrome. We assessed the frequency and nature of immune dysfunction in 24 children with genetically proven CHARGE syndrome. All patients, or their parents, completed a questionnaire on infectious history. Their immune system was extensively assessed through full blood counts, immunoglobulin levels, lymphocyte subpopulations, peripheral B- and T-cell differentiation, T-receptor excision circle (TREC) analysis, T-cell function, and vaccination responses. All CHARGE patients had a history of infections (often frequent), mainly otitis media and pneumonia, leading to frequent use of antibiotics and to hospital admissions. Decreased T-cell numbers were found in 12 (50%) patients, presumably caused by insufficient thymic output since TREC amounts were also diminished in CHARGE patients. Despite normal peripheral B-cell differentiation and immunoglobulin production in all patients, 83% of patients had insufficient antibody titers to one or more early childhood vaccinations. Based on our results, we recommend immunological evaluation of CHARGE patients with recurrent infections.

Prevalence of diphtheria and tetanus antibodies among adults in Singapore: a national serological study to identify most susceptible population groups

BACKGROUND

In view of waning antitoxin titres over time after the last vaccine dose against diphtheria and tetanus, we determined the immunity levels in adults to identify most susceptible groups for protection in Singapore.

METHODS

Our study involved residual sera from 3293 adults aged 18-79 who had participated in a national health survey in 2010. IgG antibody levels were determined using commercial enzyme-linked immunosorbent assay.

RESULTS

Overall, 92.0% (95% confidence interval [CI]: 91.1-92.9%) had at least basic protection against diphtheria (antibody levels ≥0.01 IU/ml), while 71.4% (95% CI: 69.8-72.9%) had at least short-term protection against tetanus (antibody levels >0.1 IU/ml). The seroprevalence declined significantly with age for both diseases; the drop was most marked in the 50- to 59-year age group for diphtheria and 60- to 69-year age group for tetanus. There was a significant difference in seroprevalence by residency for diphtheria (92.8% among Singapore citizens versus 87.1% among permanent residents; P = 0.001). The seroprevalence for tetanus was significantly higher among males (83.2%) than females (62.4%) (P < 0.0005).

CONCLUSIONS

It may be of value to consider additional vaccination efforts to protect older adults at higher risk for exposure against diphtheria and tetanus, particularly those travelling to areas where diphtheria is endemic or epidemic.

Immunity to diphtheria and tetanus among blood donors in Arak, central province of Iran

BACKGROUND AND OBJECTIVES

Tetanus and diphtheria are vaccine-preventable, infectious diseases with significant morbidity and mortality. Immunization by the diphtheria and tetanus toxoid (DT) has been applied in Iran for almost 50 years. However, there are very few data about the rate of immunity to these diseases in the adult population. the humoral immunity to tetanus and diphtheria among blood donors in Arak city, central provice of Iran were investigated.

PATIENTS & METHODS

A total of 530 consecutive blood donor samples were collected from Blood Transfusion Organization, Central province of Iran. All samples were tested for diphteria and tetanus IgG antibodies using enzyme-linked immunosorbent assay (ELISA).

RESULTS

From 530 cases, 91.9% were male and 8.1% were female. 99.6% of cases had protective levels of diphtheria antibody. Protective levels of tetanus antibody were found in 96% of subjects. There was not any significant difference between diphtheria and tetanus antibodies levels and age and sex.

CONCLUSION

The obtained data showed that high proportion of the adult population in Arak have sufficient protection against diphtheria and tetanus. The high protective level of immunity to diphtheria and tetanus in Iran can be due to widespread use of booster vaccines in Iranian high schools and during the military services or for pregnant women in their 3(rd) trimester.

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.

Seroprevalence of diphtheria toxoid IgG antibodies in children, adolescents and adults in Poland

BACKGROUND

Recommendations for diphtheria immunization are to apply an effective primary immunization in infancy and to maintain immunity throughout life. Immunity against diphtheria depends primarily on antibody to the diphtheria toxin. This study evaluated the seroprevalence of IgG diphtheria antitoxin in sera of healthy children, adolescents and adults in Poland.

METHODS

A total of 1387 serum samples collected between 2010 and 2012 from individuals with ages ranging from 1 month to 85 years were investigated. Antibody concentrations were measured with an enzyme-linked immunosorbent assay (Anti-Diphtheria Toxoid ELISA IgG, Euroimmun, Germany).

RESULTS

The results showed that among 1387 individuals examined, 547 (39.4%) had anti-diphtheria toxoid IgG antibody levels below 0.1 IU/ml (36.9% ≤ 18 years and 40.5% >18 years old, respectively). The 212 (50.8%) children and 542 (55.9%) adults showed only basic protection (0.1-1.0 IU/ml) and need immediate booster. High levels of anti-diphtheria toxoid IgG antibodies (>1.0 IU/ml) were found more often in children and adolescent (12.2%) than in adults (3.6%) and this was statistically significant (P < 0.05). The proportion of seronegatives (< 0.1 IU/ml) in children below 2 years old, adolescents and young adults to 25 years old decreased from 53.5% to 17.4%. However, in older individuals the seronegative proportion tended to increase with age, from 22.7% in adults (26-30 years old) to 67.1% in subjects > 60 years old. Characteristically, in individuals > 40 years old high levels of anti-diphtheria toxoid IgG antibodies (>1.0 IU/ml) were not seen. There were no statistically significant differences in results in relation to gender.

CONCLUSIONS

The present study showed inadequate immunity levels to diphtheria amongst the Polish population, especially in adults > 40 years old and children ≤ 2 years old. To prevent reemergence of diphtheria an information campaign reminding people about recommendations concerning diphtheria booster vaccination in adults should be conducted. Moreover, the immunogenicity of the DTP vaccine used in Poland should be verified.

B-lymphocyte reconstitution after repeated rituximab treatment in a child with steroid-dependent autoimmune hemolytic anemia

We report the detailed long-term reconstitution of B-lymphocyte subpopulations, immunoglobulins, and specific antibody production after two courses of rituximab in a young, previously healthy girl with steroid-dependent autoimmune hemolytic anemia. B-lymphocyte subpopulations were surprisingly normal directly after reconstitution. However, there was a slower reconstitution after the second rituximab course, especially of non-switched and switched memory B-lymphocytes, and a temporary decline in IgM below age-matched reference values.

TACI mutations and disease susceptibility in patients with common variable immunodeficiency

The most prevalent primary immunodeficiency is common variable immunodeficiency (CVID). Mutations have been described in four genes, ICOS, CD19, BAFF-R and TNFRSF13B (encoding TACI), together associated with 10-15% of CVID cases. We investigated a family with CVID and identified the heterozygous C104R TNFRSF13B mutation in two of the three index-children with CVID, a mother with selective immunoglobulin A deficiency, a mother with recurrent infections and a healthy grandfather. Remarkably, we did not find the TNFRSF13B mutation in the third index-child with CVID, despite his hypogammaglobulinaemia and decreased response to unconjugated pneumococcal vaccine. This family illustrates that TNFRSF13B mutations induce disease susceptibility rather than cause disease directly. Apparently, other genetic or environmental factors, still to be identified, contributed to the development of CVID in this family. Consequently, TNFRSF13B mutations must be interpreted with caution in the clinical setting.

Susceptibility to diphtheria in adults: prevalence and relationship to gender and social variables

Recent outbreaks of diphtheria have drawn attention to the re-emergence of this disease. This study investigated susceptibility to diphtheria in north-east Germany and its relationship to gender and social factors. A study population of 4275 individuals recruited for the population-based Study of Health in Pomerania (SHIP) was available for analysis. IgG antibodies against diphtheria toxin were determined by ELISA and were used to define susceptibility to diphtheria (i.e., IgG titres < 0.1 IU/mL). The prevalence of susceptibility to diphtheria was 32.4%. Multivariate analysis revealed 45% increased odds of women being susceptible to diphtheria. Women who had not received diphtheria toxoid vaccination during the previous 10 years had four-fold increased odds of being susceptible to diphtheria toxin compared with unvaccinated men. None of the social factors investigated was associated with susceptibility status. It was concluded that a high proportion of middle-aged adults was susceptible to diphtheria. Women lacked seroprotection more often than men, which might be explained, in part, by gender-specific immune responses following vaccination. There is a need for information campaigns to improve public awareness of these problems.

[Immunity to diphtheria among adults older than 65 years]

BACKGROUND AND OBJECTIVE

To know the immune state against diphtheria through a survey, a consultation of the vaccination documents and a seroepidemiologic study of an old population.

PATIENTS AND METHOD

The immunization status and the prevalence of antidiphtheria antibodies were determined in a representative sample (n = 231) of this population group (> 65 years). Concentrations of toxin antibodies were measured using a commercial ELISA kit. Samples with titres > 0.1 UI/ml were considered protective.

RESULTS

In the vaccination documents we only found 19 old individuals vaccinated against tetanus-diphtheria. 47.1% had no protective titres. Geometric mean titres were 0.12 UI/ml. There was no statistically significant difference between the variables age and sex and the prevalence of antibodies. 84.4% of the 122 seropositives did not report having received diphtheria vaccine and neither had documents about the vaccination.

CONCLUSION

There were almost no documents about diphtheria vaccination. Therefore, the serologic study is the only reliable way to know the immunity status against diphtheria in elderly people. Approximately 50% of this population need primary immunization. The rest of this group need to have completed antidiphtheria vaccination or a dose booster within a period of 2 years in order to guarantee protective antibody levels against diphtheria.

Effect of monophosphoryl lipid A on antibody response to diphtheria toxin and its subunits

Monophosphoryl lipid A (MPL) was evaluated for its ability to enhance the antibody response to diphtheria toxin and its fragment A and fragment B subunits. BALB/c mice were immunized subcutaneously with 1 Lf of diphtheria toxoid in the presence of 25 microg of MPL on days 0 and 14. Two weeks after the second immunization, sera were obtained from the mice and analysed for antibody response to diphtheria toxin and its subunits. A new ELISA method, developed in our laboratory, was used to measure antibody levels against the toxin, fragment A, and fragment B. It was observed that MPL significantly enhanced antibody responses to diphtheria toxin and its subunits. However, there was no statistical difference between anti-A and anti-B responses. The results indicated that MPL seems to be a potential candidate as an adjuvant for future diphtheria vaccine formulation.

Diphtheria remains a threat to health in the developing world: an overview

Changes in the epidemiology of diphtheria are occurring worldwide. A large proportion of adults in many industrialized and developing countries are now susceptible to diphtheria. Vaccine-induced immunity wanes over time unless periodic booster is given or exposure to toxigenic Corynebacterium diphtheriae occurs. Immunity gap in adults coupled with large numbers of susceptible children creates the potential for new extensive epidemics. Epidemic emergencies may not be long in coming in countries experiencing rapid industrialization or undergoing sociopolitical instability where many of the factors thought to be important in producing epidemic such as mass population movements and difficult hygienic and economic conditions are present. The continuous circulation of toxigenic C. diphtheriae emphasizes the need to be aware of epidemiological features, clinical signs, and symptoms of diphtheria in vaccine era so that cases can be promptly diagnosed and treated, and further public health measures can be taken to contain this serious disease. This overview focused on worldwide data obtained from diphtheria with particular emphasis to main factors leading to recent epidemics, new clinical forms of C. diphtheriae infections, expression of virulence factors, other than toxin production, control strategies, and laboratory diagnosis procedures.

A 5-year follow-up on antibody response after diphtheria and tetanus vaccination in hemodialysis patients

Chronic renal failure is associated with a T-cell-dependent immune defect. In the past, various studies have focused on the insufficient immune response to vaccination of hemodialysis patients. An impaired vaccination response rate has been reported for vaccines against hepatitis B, influenza, tetanus, diphtheria, and others. However, no data exist on the long-term success of vaccination against tetanus and diphtheria in these patients. The aim of the present study is to investigate seroresponse to tetanus and diphtheria vaccination over a 5-year period. Antibody levels were determined by enzyme immunoassay. Antidiphtheria antibody levels of 31 hemodialysis patients were determined 5 years after vaccination. After 5 years, 10 of 31 patients (32%) had a protective antibody level against diphtheria (>/=0.1 IU/mL), whereas 12 months after vaccination, 26 of 71 patients (37%) were protected. Also, mean antibody levels significantly decreased. Furthermore, antitetanus antibody levels of 21 patients simultaneously vaccinated against tetanus and diphtheria were investigated. After 5 years, 15 of 21 patients (71%) were protected compared with 46 of 71 patients (65%) in the hemodialysis collective studied after 12 months. In the interval between 1 and 5 years after vaccination, significantly more patients in the initial nonresponder group had died than in the responder group; therefore, the overall protection rate observed in vaccinated patients increased. Our results provide evidence that during a 5-year period, antibody persistence against tetanus toxoid is better than that against diphtheria toxoid. Therefore, detection of individual antibody concentrations may be indicated to decide on revaccination.