Immunogenicity and reactogenicity profile of inactivated vaccine among pregnant women in Pekanbaru, Indonesia

Aims:The aim of this study was to determine the immunogenicity and reactogenicity profile of the inactivated CoronaVac (Sinovac) vaccine among pregnant women in Pekanbaru, Riau, Indonesia. Methodology and results:We conducted a cross-sectional study with simple random sampling for women in at least the second trimester of pregnancy eligible for vaccination in Indonesia.Forty-five women registered for the first coronavirus disease 2019 (COVID-19) vaccination in Arifin Achmad General Hospital in August 2021 were recruited for this study.Two doses of the CoronaVac vaccine were given in 28-day intervals.Adverse reactions were assessed 7 days after each vaccination dose.Upon birth, the baby's birth weight was measured.The Chi-square test was used for the statistical analysis of categorical data, and the Mann-Whitney test was used for the statistical analysis of numerical data.While almost all (93.3%) reported no prior COVID-19 history, more than half (57.8%) respondents had detectable anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies with a median of 10.09 IU/mL.Upon first and second vaccinations, the median titter rose to 152.83 and 380.72 IU/mL, respectively.Post-vaccination antibody titer was not significantly different between pregnancy terms, but it was significantly different between antibody status prior to vaccination and gravida status.Adverse reactions showed an acceptable reactogenicity profile, with most respondents not reporting any reaction.The mean birth weight was also normal (3061.89± 414.94 g) with no significant differences between the mother's gravida status, pregnancy term at the first vaccination and antibody titer.Conclusion, significance and impact of study: CoronaVac vaccination was immunogenic and had an acceptable reactogenicity profile in pregnant women in this study.Longer follow-ups should be conducted about the long-term efficacy and safety of both the mothers and the infants.