Factors influencing antibody response after COVID-19 recombinant protein vaccination in adults: A cross-sectional observational study, in Chongqing, China.

The factors affecting the antibody responses to the ZF2001 vaccine remain unknown. To address this, we conducted a cross-sectional serological study in the real world. Adults with no prior SARS-CoV-2 infection history and received three doses of ZF2001 vaccine were invited to our study in the early stages of the COVID-19 epidemic in Chongqing between 7 April 2021 and 17 November 2021. A questionnaire survey was conducted to obtain demographic characteristics, health information, and the frequency of lifestyles at the time of enrollment. A total of 266 eligible subjects aged 18 to 86 years, with a median age of 56.00 (IQR: 34-66) participated. 68.80% of them were female. Hypertension (13.16%) and diabetes (6.02%) were common comorbidities. Serum samples were collected at one month after the third dose of ZF2001 vaccination, and serological testing was conducted using the Pseudovirus-Based Neutralization Assay. The chi-square test was employed to compare seropositivity rates, and the Mann-Whitney U test or the Kruskal-Wallis test was used to analyze the neutralizing antibodies level in stratified groups. Subsequently, univariate and multivariate linear regression analyses were conducted to identify the influencing factors. We observed that seropositivity rates was 76.32%, with 95% confidence interval (95%CI) 70.85%-81.03%, and geometric mean titer (GMT) was 120.26, with 95%CI 100.38-144.08. Age, diabetes, and frequently of alcohol were negative associations with antibody response ( = -0.2021, 95% CI: -0.2507 to -0.1535, = -0.2873, 95% CI: -0.5590 to -0.0155, = -0.2082, 95% CI: -0.3419 to-0.0746, < 0.0001,  = 0.0384,  = 0.0024). Conversely, the -interval between 1 and 2 dose and frequently of tea were positive associations with antibody response ( = 0.1369, 95% CI: 0.0463 to 0.2275,  = 0.0830, 95% CI: 0.0106 to 0.1554,  = 0.0032,  = 0.0247). Overall, the ZF2001 vaccine-induced antibody response was influenced by a multifactor that may provide a reference for the development of personalized antigen vaccines and vaccination strategies in the future.