(HealthDay News) — Health care workers (HCWs) are more likely to test positive with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and the risk for reinfection is low, according to a study published online in ERJ Open Research.
Hani Abo-Leyah, MBChB, from Ninewells Hospital and Medical School in Dundee, Scotland, and colleagues conducted a prospective observational study of HCWs in Scotland from May to September 2020 to examine whether antibodies to SARS-CoV-2 are protective against reinfection. Seroprevalence was established in the cohort of 2063 health and social care workers. New infections after antibody testing were recorded in the cohort and in matched controls.
The researchers found that 300 HCWs had a positive antibody test at enrollment (14.5%) and 11 of 231 control sera (4.8%) tested positive. The likelihood of having a positive test was increased for HCWs (odds ratio, 3.4), with dentists the most likely to test positive. Of those who had previously tested positive for SARS-CoV-2, 97.3% had positive antibodies; 18.7% had an asymptomatic infection. Overall, 38 new infections were identified in HCWs who were previously antibody-negative, and 1 symptomatic positive reinfection occurred. The risk for reinfection with SARS-CoV-2 was reduced significantly with the presence of antibodies (hazard ratio, 0.15).
“We continued to monitor staff for up to seven months and found that having a positive antibody test gave 85% protection against a future infection,” a coauthor said in a statement. “This is really good news for people who have already had COVID-19, as it means the chances of a second infection are very low.”
One author disclosed financial ties to the pharmaceutical industry.