ĐÁP ỨNG MIỄN DỊCH VÀ PHẢN ỨNG KHÔNG MONG MUỐN SAU TIÊM CHỦNG VẮC XIN PHÒNG COVID-19 (CHADOX1 NCOV-19) TẠI BỆNH VIỆN BỆNH NHIỆT ĐỚI TRUNG ƯƠNG

Abstract

SARS-CoV-2 antibody prevalence was estimated among members of a prospective cohort of NHTD healthcare workers receiving two doses of ChAdOx1 nCoV-19 vaccine.

Methods: We performed a prospective cohort study to estimate the prevalence of IgG antibodies to SARS-CoV-2 before and after ChAdOx1 nCoV-19 vaccination.

Results: 405 were vaccinated with ChAdOx1 nCoV-19 with 4-8-week (60.0%), 9-12-week (27.0%), or ≥13-week (13.0%) intervals between the two doses. Three months following series completion, 99.0% and 97.0% of vaccinated participants had >1 sample with detectable antibodies and surrogate neutralizing antibodies against SARS-CoV-2, respectively. We observed no significant differences among those with different dosing intervals at last follow up. All participants reported PCR testing for SARS-CoV-2 during the study with mild clinical symptoms and self-recover after 1 week; 2 (0.5%) were laboratory-confirmed. AEFIs were mild and more frequent post-dose 1 (80.7%) vs. post-dose 2 (21.8%). Common manifestations: swelling and pain at the injection site (56.0% and 16.8%), myalgia (41.6%; 4.4%), headache (32.0%; 3.8%) 0.8%), fever ≥ 37.5oC (28.7%; 3.6%), chills (26.8%; 2.5%), athritis (18.2%; 3.2%). Conclusions: In this population, regardless of dosing interval, ChAdOx1 nCoV-19 induced antibodies within three months of the second dose. These findings may offer flexibility to policymakers when balancing programmatic considerations with vaccine effectiveness.