SARS-CoV-2 Seroprevalence Among Firefighters in Los Angeles, California

Abstract

Objective We estimate the seroprevalence of SARS-CoV-2 antibodies among firefighters in the Los Angeles, California fire department in October 2020 and compare demographic and contextual factors for seropositivity. Methods We conducted a serologic survey of firefighters in Los Angeles, California, USA, in October 2020. Individuals were classified as seropositive for SARS-CoV-2 if they tested positive for immunoglobulin G, immunoglobulin M, or both. We compared demographic and contextual factors for seropositivity. Results Of 713 participants, 8.9% tested positive for SARS-CoV-2 antibodies. Seropositivity was not associated with gender, age, or race/ethnicity. Furthermore, firefighters who worked in zip codes with lower income or higher share of minority population did not have higher rates of SARS-CoV-2 infection. Seropositivity was highest among firefighters who reported working in the vicinity of Los Angeles International Airport, which had a known outbreak in July 2020. Conclusions Seroprevalence among firefighters was no higher than seroprevalence in the general population, suggesting that workplace safety protocols, such as access to PPE and testing, can mitigate increased risk of infection at work. Workplace safety protocols for firefighters also eliminated differences in disease burden by geography and race/ethnicity observed in the general population.