Epidemiology of SARS-CoV-2 Antibodies among Firefighters/Paramedicsof a U.S. Fire Department

Abstract

Background/Aim: Given the high risk of hazardous biological exposures encountered by first responders during routine patient rescue, it is critically important that fire departments have access to accurate up-to-date information on workforce exposure, infection, and illness to inform the best possible decisions while serving their communities. We estimate the point seroprevalence of SARS-CoV-2 antibodies in a frontline firefighter/paramedic workforce of a South Florida fire department located in the epicenter of a State outbreak.Methods: A cross-sectional study design was used to estimate the point seroprevalence of SARS-CoV-2 antibodies using a rapid IgM-IgG combined point-of-care lateral flow immunoassay among frontline firefighters/paramedics collected over a two-day period, April 16-17, 2020. Fire department personnel were emailed a survey link assessing COVID-19 symptoms and work exposures the day prior to the scheduled drive through antibody testing at a designated fire station. Off- and on-duty firefighter/paramedic personnel drove through the fire station/training facility in their personal vehicles or on-duty engine/rescue trucks for SARS-CoV-2 antibody testing. Three firefighters/paramedics did not participate because of scheduled vacation or religious reasons.Results: Among the 203 firefighters/paramedics that make up the fire department workforce, 18 firefighters/paramedics (8.9%) tested positive for SARS-CoV-2 antibodies of which 8 firefighters/paramedics (3.9%) were IgG positive only, 8 (3.9%) were IgM positive only, and 2 (0.1%) were IgG/IgM positive. The proportion of firefighters/paramedics who reported symptoms in the 2 weeks prior to antibody testing was greater among those who were positive compared to firefighters/paramedics who were antibody negative (22.2% vs. 7.7%;p=0.041). None of the antibody positive firefighters/paramedics reported receipt of the annual flu vaccine compared to firefighters/paramedics who tested negative for SARS-CoV-2 antibodies (0.0% vs. 21.0%; p=.031).Conclusions: Rapid SARS-CoV-2 IgM-IgG antibody testing documented early- and late-stage infection in a firefighter workforce providing insight to a broader medical surveillance project on return to work for firefighters/paramedics.