Tetanus seroprotection among children in the Democratic Republic of the Congo, 2013-2014

Abstract

Background: Tetanus is a potentially fatal disease that is preventable through vaccination. While the Democratic Republic of the Congo (DRC) has continued to improve implementing routine vaccination activities throughout the country, they have struggled to maintain high childhood vaccine coverage. This study aims to examine the seroprevalence of tetanus in children 6 to 59 months to identify areas for intervention and improvement of vaccination coverage.

Methods: In collaboration with the 2013-2014 Demographic and Health Survey, we assessed the seroprevalence of tetanus antibodies among children in the DRC. Dried blood spot samples collected from children 6-59 months of age were processed using a prototype DYNEX Multiplier® chemiluminescent automated immunoassay instrument with a multiplex measles, mumps, rubella, varicella and tetanus assay. Multivariable logistic regression was used to determine factors associated with tetanus vaccination and seroprotection.

Results: Overall, 36.1% of children 6-59 months of age reported receiving at least 1 dose of tetanus vaccine while 28.7% reported receiving 3 doses; tetanus seroprotection was 40%. Increasing age in children was associated with decreased tetanus seroprotection, but increased number tetanus vaccinations received. Factors related to increased tetanus seroprotection included number of children in the household, wealth index of the family, urban residence compared to rural, level of maternal education, and province and geography.

Conclusions: Our findings in this nationally representative sample indicate that serology biomarkers may help identify children who are not fully immunized to tetanus more accurately than reported vaccination. While children may be captured for routine immunization activities, as children age, decreasing seroprevalence may indicate additional need to bolster routine vaccination activities and documentation of vaccination in school aged children. Additionally, the study highlights gaps in rural residential areas and vaccination coverage based on maternal education, indicating that policies targeting maternal education and awareness could improve the coverage and seroprevalence of tetanus antibodies in the DRC.

Fig 1. Attrition table.

Study inclusion for assessment of tetanus seroprevalence among 6- to 59-month-old EDS-RDC II respondents (unweighted).

Fig 2. Tetanus seropositivity and vaccination trends by age.

Tetanus seroprotection and full vaccination coverage (documentation of three doses of tetanus containing vaccine) according to age (in months) among children 6–59 months old in the EDS-RDC II (linear trend lines in black).

Fig 3. Tetanus seroprotection by province and age among children 6–59 months old in the EDS-RDC II.

Fig 4. Tetanus seroprotection by province and age among children 6–59 months old who reported receiving 0 vs. 3 doses of tetanus containing vaccine in the EDS-RDC II.

Fig 5. Odds ratios of tetanus seroprotection.

Forest plot of odds ratios from weighted logistic regression of sociodemographic factors/characteristics associated with tetanus seroprotection among children 6–59 months old in the EDS-RDC II, unadjusted and stratified by residence type (adjusted for all other variables in the model).