Seroprevalence of antibodies against diphtheria, tetanus, and pertussis across various age groups during the post-COVID-19 pandemic period in Chonburi Province, Thailand

Abstract

Background: Limited data exists regarding population immunity against diphtheria, tetanus, and pertussis in Thailand during the post-COVID-19 pandemic period. This study aimed to evaluate the age-specific seroprevalence of anti-diphtheria toxoid (anti-DT) IgG, anti-tetanus toxoid (anti-TT) IgG, and anti-pertussis toxin (anti-PT) IgG in individuals across diverse age groups in Chonburi province, Thailand following the COVID-19 pandemic. Methods: Between October 2022 and January 2023, a total of 657 participants from Chonburi Province, Thailand, were included in this study. The participants were categorized into 9 age groups: 70 years. Analysis of anti-DT, anti-TT, and anti-PT IgG levels was conducted using commercial ELISA kits (EUROIMMUN, Lübeck, Germany). Results: Overall, 65.4 % of the population had seroprotection against diphtheria (antibody level ≥0.1 IU/mL), while 95.1 % had seroprotection against tetanus (antibody level ≥0.1 IU/mL). The 31–40 years age group exhibited the lowest seroprotection for diphtheria (48.9 %), and the >70 years age group had the lowest seroprotection for tetanus (73.3 %). The <5 years age group showed the highest seropositive rate and highest geometric mean titers for anti-PT IgG. On the contrary, the majority of individuals over 11 years of age displayed anti-PT IgG levels below 40 IU/mL. Conclusions: To prevent diphtheria and pertussis outbreaks in Chonburi province, implementing catch-up vaccination is necessary. Targeted interventions should be deployed to enhance vaccination coverage among the susceptible population.

Keywords

• Seroprevalence
• Diphtheria
• Tetanus
• Pertussis
• Population