Evaluation of diphtheria antibody titers after 2 doses of tetanus - diphtheria (Td) vaccine in EaSup district, Dak Lak province and Dak Song district, Dak Nong province in 2021 - 2022

Abstract

A cross - sectional descriptive study was conducted on 763 persons to evaluate the diphtheria antibody titers after 2 doses of vaccine Tetanus - diphtheria (Td) in EaSup district, Dak Lak province and Dak Song district, Dak Nong province from 8/2021 to 8/2022. The results showed that people with fully protective antibody levels accounted for a high rate of 87.7%, and achieved herd immunity. The partial protection was 8.9% and 3.4% was unprotected after the 2 doses of Td. The proportion of fully protective antibody in group under 18 years old (90.3%) was higher than in the group over 18 years old (86.8%). There 60.0% of people in the group under 18 years of age could achieve the titer of diphtheria antitoxin antibody at a fully protective level after 2 doses of Td, which was higher than the possibility of achieving a partially protective antibody level compared with that of the group over 18 years old (OR = 0.4, 95%CI = 0.20 - 0.85). The results of the study will be basic data for developing a plan to add the third dose of Td vaccine or a booster dose after 10 years to maintain lifelong protection for adults and continue to carry out longitudinal studies for monitoring diphtheria concentrations antibodies in the community after 5, 7, 10 and 15 years.