Seroprevalence of COVID-19 neutralizing antibodies among multi-ethnic staff of an Asian primary healthcare institution: insights from point-of-care testing and implications for booster vaccination decisions

Abstract

Background COVID-19 vaccines have been crucial for establishing immunity; however, emerging data suggest vaccine efficacy is reduced within six months. Healthcare staff face an elevated COVID-19 risk and should make an informed decision to receive timely boosters to maintain their immunity. This study aims to determine the COVID-19 neutralizing antibody (nAb) seroprevalence among primary care staff and the impact of serological testing on their vaccination decision. Methods This cross-sectional study involved multidisciplinary primary healthcare professionals working in 10 public primary care clinics from December 2022 to July 2023. A questionnaire captured sociodemographic data, COVID-19 related history and attitudes toward serological testing. Their COVID-19 nAb levels were measured via point-of-care CoVIm™ Rapid SARS-CoV-2 nAb Test and laboratory cPass™ SARS-CoV-2 nAb Detection Kit. Results The study included 474 subjects, mostly female (88.8%), with a mean age of 40.6 years (SD = 12.3). All received at least two COVID-19 vaccinations, and 80.6% reported at least one infection. COVID-19 nAb seroprevalence was high (99.2%). Post-vaccination, 79.7% contracted COVID-19, with the median time to infection being 163 days. Most staff (93.9%) desired to know their COVID-19 immunity status through a finger pick test (77.0%) instead of venepuncture. Over two-thirds (68.1%) indicated the results would influence their booster vaccination decision. Conclusion The study revealed a high seroprevalence of COVID-19 nAb among the fully vaccinated participating staff. The necessity for timely boosters is underscored by 79.7% contracting COVID-19 post-vaccination. Most subjects were willing to undergo point-of-care testing, with results potentially influencing their decisions for booster vaccination.