SARS-CoV-2 antibody seroprevalence among firefighters in Orange County, California

Abstract

ObjectivesWe conducted serological SARS-CoV-2 antibody testing from October to November 2020 to estimate the SARS-CoV-2 seroprevalence among firefighters/paramedics in Orange County (OC), California.MethodsOC firefighters employed at the time of the surveillance activity were invited to participate in a voluntary survey that collected demographic, occupational and previous COVID-19 testing data, and a SARS-CoV-2 immunoglobulin (Ig)G antibody blood test. We collected venous blood samples using mobile phlebotomy teams that travelled to individual fire stations, in coordination with an annual tuberculosis testing campaign for firefighters employed by OC Fire Authority (OCFA), and independently for firefighters employed by cities. We estimated seroprevalence and assessed several potential predictors of seropositivity.ResultsThe seroprevalence was 5.3% among 923 OCFA personnel tested, with 92.2% participating. Among firefighters self-reporting a previous positive COVID-19 antibody or PCR test result, twenty-one (37%) did not have positive IgG tests in the current serosurvey. There were no statistically significant differences in demographic characteristics between cases and non-cases. Work city was a significant predictor of case status (p=0.015). Seroprevalence (4.8%) was similar when aggregated across seven city fire departments (42%–65% participation). In total, 1486°C fire personnel were tested.ConclusionUsing a strong serosurvey design and large firefighter cohort, we observed a SARS-CoV-2 IgG seroprevalence of 5.3%. The seroprevalence among OC firefighters in October 2020 was lower than the general county population estimated seroprevalence (11.5%) in August. The difference may be due in part to safety measures taken by OC fire departments at the start of the pandemic, as well as differences in antibody test methods and/or duration of antibody response.

Effect of socioeconomic factors during the early COVID-19 pandemic: a spatial analysis

“…This area of high risk observed in our study consists of minority communities who may also reside in crowded neighborhoods, may not be able to physically distance, and have other comorbidities that may worsen their COVID-19 prognosis [ 35 ]. An occupational study on seroprevalence among firefighters also identified a higher proportion of Hispanic firefighters who were reluctant to participate in disease surveillance activities, suggesting there may be hesitancy towards public health activities [ 36 ].…”

Missing science: A scoping study of COVID-19 epidemiological data in the United States

“…Several studies of infection predictors examined risk factors within specific settings and sub-populations, including face coverings and distancing among occupants of a military ship [210], ethnic composition and exposure risk factors in employees of industrial facilities [222,241,265,270,282], including one study that compared the incidence before and after mitigation strategies such as masking and barriers in a meat processing facility [265], shelter residence status among people experiencing homelessness [271,302], screening strategies and staffing levels in skilled nursing facilities [227,228,243,247,272], housing type and athletic participation among college students [234,300], and community exposures and symptomatic contacts in children [242,261,264,267,277,280,283,294,295,306]. Several studies use seroprevalence surveys or administrative data to examine infection risk factors among healthcare workers and first responders [224,233,239,257,259,274,289,299]. One analytic study evaluated serial testing of healthcare workers in a skilled nursing facility [272].…”