Kinetics of neutralising antibodies against Omicron variant in Vietnamese healthcare workers after primary immunisation with ChAdOx1-S and booster with BNT162b2

• DOI: 10.1101/2022.06.20.22276596
• Publication Date: 2022-06-22T01:11:04Z
• Authors: Nguyen Van Vinh Chau; Lam Anh Nguyet; Nguyen Thanh Dung; Vo Minh Quang; Nguyen Thanh Truong; Le Mau Toan; Le Manh Hung; Dinh Nguyen Huy Man; Dao Bach Khoa; Nguyen Thanh Phong; Nghiem My Ngoc; Huynh Phuong Thao; Dinh Thi Bich Ty; Pham Ba Thanh; Nguyen Thi Han Ny; Le Kim Thanh; Cao Thu Thuy; Nguyen To Anh; Nguyen Thi Thu Hong; Le Nguyen Truc Nhu; Lam Minh Yen; Guy Thwaites; Tran Tan Thanh; Le Van Tan
• Keywords: Booster (rocketry); Booster dose; Vietnamese

Abstract We studied the development and persistence of neutralising antibodies against SARS-CoV-2 ancestral strain, Delta Omicron (BA.1 BA.2) variants in Vietnamese healthcare workers (HCWs) up to 15 weeks after booster vaccination. included 47 HCWs with different pre-existing immune statuses (group 1 (G1): n=21, group 2 (G2): n=26 without prior breakthrough variant infection, respectively). The study participants had completed primary immunisation ChAdOx1-S vaccination BNT162b2. Neutralising were measured using a surrogate virus neutralisation assay. Of 21 G1, variant, BA.1 BA.2 (almost) abolished at month 8 second dose, but all detectable viruses week two post dose. 26 G2, antibody levels significantly higher than those corresponding infection before At vaccination, dropped significantly, more profound changes observed infection. Booster enhanced activities strain as compared induced by These responses maintained high for least weeks. Our findings emphasise importance first dose producing cross-neutralising variant. A might be needed maintain long-term protection