ABSTRACT
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the latest pandemic and the most significant challenge in public health worldwide. Studying the longevity of naturally developed antibodies is highly important clinically and epidemiologically. This paper assesses the longevity of antibodies developed against nucleocapsid protein amongst our health-care workers. Methods: This longitudinal cohort study was conducted at a tertiary hospital, Saudi Arabia. Anti-SARSsCoV-2 antibodies were tested among health-care workers at three-point intervals (baseline, eight weeks, and 16 weeks). Results: Of the 648 participants, 112 (17.2%) tested positive for Coronavirus (COVID-19) by PCR before the study. Of all participants, 87 (13.4%) tested positive for anti-SARS-CoV-2 antibodies, including 17 (2.6%) participants who never tested positive for COVID-19 using rt-PCR. Out of the 87 positive IgG participants at baseline, only 12 (13.7%) had remained positive for anti-SARS-CoV-2 antibodies by the end of the study. The IgG titer showed a significant reduction in values over time, where the median time for the confirmed positive rt-PCR subgroup from infection to the last positive antibody test was 70 (95% CI: 33.4-106.5) days. Conclusion: Health-care workers are at high risk of exposure to the SARS-CoV-2 virus, and contracting an asymptomatic infection is not unlikely. Developing and sustaining natural immunity differs from one person to another, while the rate of positive IgG anti-SARS-CoV-2 wanes over time. Clinicaltrialsgov Identifier: NCT04469647, July 14, 2020.
ABSTRACT
Background: The nature of the healthcare workers' jobs standing at the frontline against the coronavirus disease 2019 (COVID-19) puts them at a higher risk of unknowingly contracting the disease and potentially contributing to the spread. This study aims to assess the overall positive seroconversion prevalence of SARS-CoV-2. Methods: This is a longitudinal cohort study of healthcare workers at Johns Hopkins Aramco Healthcare (JHAH). JHAH is a tertiary hospital located in Dhahran serving patients in several districts in the Eastern Province of Saudi Arabia. Participants were recruited between June and December 2020. Each participant had a serology blood test and completed the World Health Organization's risk factor assessment questionnaire. Results: This study included 682 participants working in JHAH, representing 15.7% of our population. Out of the 682 participants, 15.2% had a positive SARS-CoV-2 rt-PCR before taking part in the study. However, only 87 tested positive for SARS-CoV-2 antibodies, a prevalence of 12.7% of all participants. Out of the 87 positives for SARS-CoV-2 antibodies, 17 participants never tested positive for COVID-19 rt-PCR, a prevalence of 2.9%. Moreover, not properly using alcohol-based hand rub or soap and water after the risk of body fluid exposure and wearing personal protective equipment when indicated were found to be statistically significant to having a positive SARS-CoV-2 IgG assay. Conclusion: Positive seroconversion rate was considerably low during the first wave of COVID-19 amongst JHAH's healthcare workers and similar to other healthcare organizations in Saudi Arabia. Seropositivity correlated significantly with following infection prevention and control recommendations. Clinicaltrialsgov Identifier: NCT04469647.