SARS-CoV-2 antibodies in patients and health care workers

To date, only limited data are available on the prevalence of SARS-CoV-2 antibodies and the duration of immunity after exposure to SARS-CoV-2. Moreover, identification of risk markers/factors for SARS-CoV-2 infection and outcomes of COVID-19 in both healthcare workers and in a diverse patient population admitted for non-COVID related symptoms remains an unmet need. This study consists of 2 parts: a longitudinal study enrolling 3.000 health care professionals of the Medical University of Vienna and the Vienna General Hospital (AKH) testing their antibody status 6 times over a period of 12 months, and a serial cross-sectional study of 3.000 patients (i.e., a total of 9.000 patients) admitted to the Vienna General Hospital for non-COVID-19-related symptoms at 3 different time points during this pandemic. The findings of this project will provide relevant information on seroprevalence, duration of antibody detection and whether it can serve as an indicator of immunity as well as possible reinfections.

This research provides a comprehensive understanding of SARS-CoV-2 exposure and its long-term effects, focusing on healthcare workers, patients, and individuals with long-COVID syndrome. We assessed the prevalence of SARS-CoV-2 nucleoprotein antibodies among healthcare workers and a diverse patient population during different phases of the pandemic at an Austrian academic medical center. By analyzing over 12,000 blood samples collected during different phases of the pandemic, we found that both groups- healthcare workers and patients - had a similar level of exposure to the virus. Notably, despite Austria's extensive per capita PCR testing and robust containment policies, the observed exposure exceeded the officially reported infection rates, suggesting that a significant number of infections may have gone undetected. Furthermore, the data revealed an unexpected finding: transmission rates among children were higher than previously assumed, as infection rates did not significantly differ between adults and children throughout the study period. These results highlight the value of antibody testing in uncovering the true extent of viral spread and shaping effective public health strategies. Despite the higher seroprevalence among healthcare workers and patients compared to the general population, the findings also provide reassurance that healthcare environments with robust safety protocols appear to mitigate additional risk, aligning exposure levels with those seen in the broader community. Additionally, the study observed that individuals who received COVID-19 vaccines reported fewer symptoms such as fatigue and organ-related issues compared to those who were unvaccinated. Vaccination also appeared to reduce the reactivation of other dormant viruses, such as Epstein-Barr virus, which are often linked to long-term health complications. These findings underscore the broader benefits of COVID-19 vaccines, beyond preventing acute infections, by potentially mitigating long-term sequelae of the virus. As suche, these insights emphasize the critical role of vaccination in managing both immediate and lasting impacts of the pandemic. Together, these studies emphasize the importance of comprehensive monitoring through antibody testing and vaccination to understand and address both the immediate and prolonged impacts of SARS-CoV-2.