Prevalence of COVID-19 IgG Antibodies in a Cohort of Municipal First Responders

Abstract

Background: Although first responders (FRs) represent a high-risk group for exposure, little information is available regarding their risk of coronavirus disease 2019 (COVID-19) infection. The purpose of the current study was to determine the serological prevalence of past COVID-19 infection in a cohort of municipal law enforcement (LE) and firefighters (FFs). Methods: Descriptive analysis of a de-identified data reporting Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) immunoglobulin G (IgG), or COR2G, serology results for municipal FRs. As part of the serology process, FRs were surveyed for COVID-19-like symptoms since February 2020 and asked to report any prior COVID-19 nasal swab testing. Descriptive statistics and two-sided Chi Square tests with Yates correction were used to compare groups. Results: Of 318 FRs, 225 (80.2%) underwent serology testing (LE: 163/207 [78.7%]; FF: 92/111 [82.9%]). The prevalence of positive serology for all FRs tested was 3/255 (1.2%). Two LE (1.2%) and one FF (1.1%) had positive serology (P = 1.0). Two hundred and twenty-four FRs responded to a survey regarding prior symptoms and testing. Fifty-eight (25.9%) FRs (44 LE; 14 FFs) reported the presence of COVID-19-like symptoms. Of these, only nine (15.5%) received reverse transcriptase – polymerase chain reaction (RT-PCR) testing; none were positive. Two of the three FRs with positive serology reported no COVID-19-like symptoms and none of these responders had received prior nasal RT-PCR swabs. The overall community positive RT-PCR rate was 0.36%, representing a three-fold higher rate of positive seroprevalence amongst FRs compared with the general population (P = .07). Conclusions: Amongst a cohort of municipal FRs with low community COVID-19 prevalence, the seroprevalence of SARS-CoV-19 IgG Ab was three-fold greater than the general community. Two-thirds of positive FRs reported a lack of symptoms. Only 15.5% of FRs with COVID-19-like symptoms received RT-PCR testing. In addition to workplace control measures, increased testing availability to FRs is critical in limiting infection spread and ensuring response capability.

Seroprevalence of SARS-CoV-2 Among Firefighters/Paramedics in San Francisco, CA

“… 12 Studies of emergency responders in Arizona and Minnesota conducted from late April to May 2020 found seroprevalences of 1.5% and 1.2% respectively. 13 , 14 In April 2020, during a local outbreak in South Florida, seroprevalence was found to be 8.9% in emergency responders. 15 …”

Anti-SARS-CoV-2 IgA Identifies Asymptomatic Infection in First Responders

“…Serologic surveys of first responders have shown variable results with some showing rates similar to the general population and others showing higher rates (see Table 1). [1][2][3][4][5][6][7] Some of this variability may relate to differences in access to personal protective equipment (PPE) and infection control policies. [8] Because high-risk groups such as older individuals and individuals with significant comorbidities may be underrepresented among first responders, the proportion of infections which are asymptomatic in this group may be higher.…”

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

“…[6] Although it has been demonstrated that healthcare workers with high levels of patient contact experience greater odds of seropositivity than the general population or other public service employees, [4,7] seroprevalence among first responders or firefighters do not appear to significantly deviate from community estimates. [1,2,6] In this study we conducted a serologic survey to estimate the prevalence of SARS-CoV-2 antibodies among firefighters in the Los Angeles Fire Department (LAFD) and tested for associations between seroprevalence and individual characteristics.…”

“…On the lower end, seroprevalence estimates ranged from 1.1% and 1.5% in Rochester (May) and Arizona (April/May), respectively. [1,2] In May/June seroprevalence was 5.4% in Cleveland 6.9% in Detroit. [3,4] In a single fire department located at the epicenter of an outbreak in South Florida, seroprevalence was 8.9% in April.…”

“…[6] Although it has been demonstrated that healthcare workers with high levels of patient contact experience greater odds of seropositivity than the general population or other public service employees,[4,7] seroprevalence among first responders or firefighters do not appear to significantly deviate from community estimates. [1,2,6]…”