This article focuses on a cross-sectional serologic study conducted among healthcare workers (HCWs) in a tertiary care hospital in Taiwan, conducted from August 2022 to February 2023. The study was to evaluate the antibody responses to COVID-19 vaccination against Omicron subvariants BA.1, BA.4, and BA.5, especially considering the variations in prior exposure to the virus infection. This research also assessed the effectiveness of infection control and prevention (ICP) measures and vaccination policies within the Taiwanese hospital setting.
The study involved 777 HCWs, with most (99%) having received SARS-CoV-2 vaccination. In total, 57.7% of participants had faced infection with SARS-CoV-2, with some remaining asymptomatic. The distribution of the SARS-CoV-2 Anti-Spike S1 protein IgG was 40,000 AU/mL for 20.2% of participants, and the decay curve for Anti-S was less than 20,000 AU/ml after 120 days. Approximately 50% neutralization occurred with an Anti-S of 55,000 AU/ml.
This comprehensive study concluded that 20.2% of HCWs achieved seroprotection against the Omicron subvariants BA.1, BA.4, and BA.5. Their immunity against aforementioned Omicron subvariants was strengthened by following vaccination protocols and having developed a natural immunity from SARS-CoV-2 exposure.
Taiwan, which had been significantly impacted by the 2003 SARS outbreak, promptly enforced strict ICP measures in January 2020 to battle the global COVID-19 pandemic. These ICP measures include quarantining, contact tracing, social distancing, isolation of patients with COVID-19, wearing of surgical masks, wiping out cases, and allocation of personal protective equipment. Taiwan has successfully avoided large-scale exposure to the virus, thus relying on vaccinations for protective immunity.
This study is a significant contribution to the global understanding of HCWs’ vaccination responses, providing vital data on the effectiveness of the vaccine against Omicron strains. It also underscores the value of robust infection control and prevention measures.
Source: https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-024-09411-z