Chayachinda C.Watananirun K.Phatihattakorn C.Anuwutnavin S.Niyomnaitham S.Phongsamart W.Lapphra K.Wittawatmongkol O.Rungmaitree S.Jansarikit L.Boonnak K.Wongprompitak P.Senawong S.Upadhya A.Toh Z.Q.Licciardi P.V.Chokephaibulkit K.Mahidol University2023-07-282023-07-282023-01-01Human Vaccines and Immunotherapeutics (2023)21645515https://repository.li.mahidol.ac.th/handle/123456789/88118This open-labeled non-inferiority trial evaluated immunogenicity and reactogenicity of heterologous and homologous COVID-19 vaccination schedules in pregnant Thai women. 18–45-year-old pregnant women with no history of COVID-19 infection or vaccination and a gestational age of ≥12 weeks were randomized 1:1:1 into three two-dose primary series scheduled 4 weeks apart: BNT162b2-BNT162b2 (Group 1), ChAdOx1-BNT162b2 (Group 2), and CoronaVac-BNT162b2 (Group 3). Serum antibody responses, maternal and cord blood antibody levels at delivery, and adverse events (AEs) following vaccination until delivery were assessed. The 124 enrolled participants had a median age of 31 (interquartile range [IQR] 26.0–35.5) years and gestational age of 23.5 (IQR 18.0–30.0) weeks. No significant difference in anti-receptor binding domain (RBD) IgG were observed across arms at 2 weeks after the second dose. Neutralizing antibody geometric mean titers against the ancestral Wuhan strain were highest in Group 3 (258.22, 95% CI [187.53, 355.56]), followed by Groups 1 (187.47, 95% CI [135.15, 260.03]) and 2 (166.63, 95% CI [124.60, 222.84]). Cord blood anti-RBD IgG was correlated with, and equal to or higher than, maternal levels at delivery (r = 0.719, P <.001) and inversely correlated with elapsed time after the second vaccination (r = −0.366, P <.001). No significant difference in cord blood antibody levels between groups were observed. Local and systemic AEs were mild-to-moderate and more frequent in Group 2. Heterologous schedules of CoronaVac-BNT162b2 or ChAdOx1-BNT162b2 induced immunogenicity on-par with BNT162b2-BNT162b2 and may be considered as alternative schedules for primary series in pregnant women in mRNA-limited vaccine settings.MedicineArticleSCOPUS10.1080/21645515.2023.22286702-s2.0-851652104872164554X37439770