Abstract
Background: To mitigate a national shortage of WIBP-CorV COVID-19 vaccine, China’s regulator approved administering BBIBP-CorV after WIBP-CorV for completion of a primary series. In a pragmatic observational study, we compared immunogenicity and safety of a primary series of WIBP-CorV followed by BBIBP-CorV with a primary series of two doses of BBIBP-CorV.
Methods: We invited healthy 18-59-years-old adults who had already received either WIBP-CorV or BBIBP-CorV as their first dose in a primary series to participate in this observational cohort study. Subjects who had received WIBP-CorV as their first dose became the observation group; subjects who had received BBIBP-CorV as their first dose became the control group. All participants received BBIBP-CorV as their second dose. We obtained sera 1, 2, and 6 months after second doses for nAb titer measurement by micro-neutralization cytopathic effect assay with SARS-CoV-2 strain HB01, standardized with WHO International Standard for anti-SARS-CoV-2 immunoglobulin. Safety was assessed for the 7 days after administration of second doses.
Results: Between March and December 2021, 275 subjects were included in the observation group and 133 in the control group. Neutralizing seropositivity (≥1:4) rates were 98.91 % and 99.25 % at 1 month and 53.16 % and 70.69 % at 6 months. One-month geometric mean titers (GMTs) were 21.33 and 22.45; one-month geometric mean concentrations (GMCs) were 227.71 IU/mL and 273.27 IU/mL. One to two months after vaccination, observation group seropositivity rates and titers were not significantly different to the control group’s. Adverse reaction rates were 11.27 % and 18.80 %, all mild or moderate in severity.
Conclusions: Both primary series were immunogenic; immunogenicity of WIBP-CorV followed by BBIBP-CorV was not different than immunogenicity following two doses of BBIBP-CorV for two months after vaccination; safety profiles were acceptable for both regimens. BBIBP-CorV can be used to complete a primary series that started with WIBP-CorV.
Keywords: COVID-19; Immune persistence; Immunogenicity; Inactivated vaccine; Replacement vaccine; Safety.
【저자키워드】 COVID-19, immunogenicity, Safety., Inactivated vaccine, immune persistence, Replacement vaccine, 【초록키워드】 COVID-19 vaccine, vaccination, Safety, severity, anti-SARS-CoV-2, China, Immunoglobulin, sera, Mild, WHO, moderate, safety profile, BBIBP-CorV, NAb, Cytopathic effect, administration, dose, Pragmatic, Adverse reaction, Standard, observation, Observational cohort study, control group, subject, second dose, first dose, GMTs, regimens, GMCs, geometric mean concentration, doses, National, geometric mean titer, SARS-CoV-2 strain, replacement, Complete, mitigate, healthy, approved, can be used, not different, All participant, not significantly different, 【제목키워드】 COVID-19 vaccine, vaccination, Safety, inactivated, Observational cohort study,