Background: The ChAdOx1 nCoV-19 vaccine has been widely administered against SARS-CoV-2 infection; however, data regarding its immunogenicity, reactogenicity, and potential differences in responses among Asian populations remain scarce. Methods: 270 participants without prior COVID-19 were enrolled to receive ChAdOx1 nCoV-19 vaccination with a prime–boost interval of 8–9 weeks. Their specific SARS-CoV-2 antibodies, neutralizing antibody titers (NT50), platelet counts, and D-dimer levels were analyzed before and after vaccination. Results: The seroconversion rates of anti-RBD and anti-spike IgG at day 28 after a boost vaccination (BD28) were 100% and 95.19%, respectively. Anti-RBD and anti-spike IgG levels were highly correlated (r = 0.7891), which were 172.9 ± 170.4 and 179.3 ± 76.88 BAU/mL at BD28, respectively. The geometric mean concentrations (GMCs) of NT50 for all participants increased to 132.9 IU/mL (95% CI 120.0–147.1) at BD28 and were highly correlated with anti-RBD and anti-spike IgG levels (r = 0.8248 and 0.7474, respectively). Body weight index was statistically significantly associated with anti-RBD IgG levels ( p = 0.035), while female recipients had higher anti-spike IgG levels ( p = 0.038). The GMCs of NT50 declined with age ( p = 0.0163) and were significantly different across age groups (159.7 IU/mL for 20–29 years, 99.4 IU/mL for ≥50 years, p = 0.0026). Injection-site pain, fever, and fatigue were the major reactogenicity, which were more pronounced after prime vaccination and in younger participants (<50 years). Platelet counts decreased and D-dimer levels increased after vaccination but were not clinically relevant. No serious adverse events or deaths were observed. Conclusion: The vaccine is well-tolerated and elicited robust humoral immunity against SARS-CoV-2 after standard prime–boost vaccination in Taiwanese recipients.
【저자키워드】 Vaccine, ChAdOx1 nCoV-19, Asian populations, 【초록키워드】 COVID-19, SARS-CoV-2, vaccination, reactogenicity, fatigue, body weight, Population, Humoral immunity, SARS-CoV-2 antibodies, anti-Spike IgG, response, Fever, female, Pain, death, Platelet, age, group, boost, ChAdOx1 nCoV-19 vaccine, Neutralizing antibody titer, Platelet count, D-dimer level, anti-RBD, Anti-RBD IgG, Asian, Serious Adverse Event, 95% CI, recipients, participant, GMCs, geometric mean concentration, seroconversion rate, recipient, Administered, GMC, robust, enrolled, analyzed, significantly, clinically, correlated, elicited, statistically, declined, receive, anti-spike IgG level, 【제목키워드】 immunogenicity, Taiwan, Standard,