Diphtheria seroprotection among Indonesian children: Community Health Surveys Riskesdas 2007, 2013 and 2018

Area of Science:

• Immunology
• Public Health
• Epidemiology

Background:

• Diphtheria remains a public health issue in Indonesia despite routine childhood immunizations.
• Assessing diphtheria immunity trends and identifying at-risk populations is vital for effective control strategies.

Purpose of the Study:

• To evaluate temporal trends in diphtheria immunity among Indonesian children (1-14 years).
• To identify age groups with suboptimal protection and factors influencing seroprotection.
• To assess the impact of immunization programs and potential booster strategies.

Main Methods:

• Analysis of diphtheria IgG antibody data from Indonesian Community Health Surveys (Riskesdas) in 2007, 2013, and 2018.
• Inclusion of 6,622 to 7,203 children per survey year.
• Bivariate and multivariate logistic regression to determine seroprotection predictors.

Main Results:

• Overall seroprotection ranged from 71.1% to 83.6%, showing a 2-3 fold increase in 2018.
• Lowest IgG levels observed in children aged 1-6 years, with waning immunity after age 10.
• Complete diphtheria-tetanus-pertussis (DTP) immunization was the strongest predictor of seroprotection in younger children.
• Maternal education and household economic status also correlated with seroprotection in specific surveys.
• Introduction of DTP4 booster correlated with higher IgG concentrations in 1-2 year olds in 2018.

Conclusions:

• Diphtheria immunity in Indonesian children is suboptimal, particularly in those aged 5-6 years.
• Maintaining high DTP immunization coverage is essential for sustained population immunity.
• Booster vaccination strategies should be considered to address waning immunity and ensure long-term protection.