Immunogenicity of Oxford-AstraZeneca COVID-19 vaccine in Vietnamese healthcare workers
Van Vinh Chau N., Nguyet LA., Truong NT., Toan LM., Dung NT., Hung LM., Nhan MT., Huy Man DN., Ngoc NM., Thao HP., Hoang Tu TN., Mai HK., Hung DT., Han Ny NT., Thanh LK., Anh NT., Thu Hong NT., Truc Nhu LN., Yen LM., Choisy M., Thanh TT., Thwaites G., Van Tan L., OUCRU COVID-19 Research Group None.
ABSTRACT We studied the immunogenicity of Oxford-AstraZeneca vaccine in Vietnamese healthcare workers. We collected blood samples before each dose, at 14 days after each dose, and month 1 and 3 after dose 1 from each participant alongside demographics data. We measured neutralizing antibodies using a surrogate virus neutralization assay. The 554 study participants (136 males and 418 females) were aged between 22-71 years (median: 36 years). 104 and 94 out of 144 selected participants were successfully followed up at 14 days after dose 2 and 3 months after dose 1, respectively. Neutralizing antibodies increased after each dose, with the sero-conversion rate reaching 98.1% (102/104) at 14 days after dose 2. At month 3 after dose 1, neutralizing antibody levels decreased, while 94.7% (89/94) of the study participants remained seropositive. Oxford-AstraZeneca COVID-19 vaccine is immunogenic in Vietnamese healthcare workers. The requirement for a third dose warrants further research.