First Responders Have a Higher Risk of COVID-19 Infection than Other Essential Workers
First responders are twice as likely to become infected with COVID-19 in the workplace as health care workers and other essential workers, and this increases significantly after adjusting for cofounding factors.
The FDA and CDC have recommended booster vaccines for people with “frequent institutional or occupational exposure” to COVID-19, but there is no definitive consensus of which careers should be considered high-risk.
The study took place from July 20, 2020, to March 14, 2021. Participants were COVID-19 negative, had not been vaccinated, had frequent direct contact with others at work (within 3 feet), worked 20 or more hours each week, and submitted weekly nasal swab specimens for reverse transcriptase polymerase chain reaction analysis. Participants were representative of the Arizona Healthcare, Emergency Response, and Other Essential Workers Study (AZ HEROES), a statewide prospective cohort created to study COVID-19 infection and immunity among frontline and essential workers.
The study cohort was comprised of 1766 Arizona workers 18-85 years of age (mean age 43.8 years); 44.2% were health care personnel, 22.4% were first responders, and 33.4% were other essential workers. Of these, 1093 (61.9%) were female, 401 (22.7%) were Hispanic, and 1530 (86.6%) were White. These cohort demographics were fairly aligned with the investigators’ original sampling targets.
The “first responders” included correctional officers, firefighters, law enforcement (including US Customs and Border Protection), and emergency medical services (EMS) workers. The category “other essential workers” included persons in other work environments that prevented physical distancing, including frontline education, childcare or social work, frontline retail or hospitality, essential operations in government and nonprofit sectors requiring in-person work (postal workers, 911 call center operators), and essential infrastructure workers (waste management, agriculture, utility services).
The investigators used negative binomial regression to model COVID-19 infection by occupation and estimate adjusted and unadjusted incidence rate ratios (IRRs). They utilized the least absolute shrinkage and selection operator (LASSO) method to generate a parsimonious multivariable model. The primary source of exposure studied was occupational hazard, but investigators also assessed sociodemographic factors, health status, and community exposure.
The crude incidence of COVID-19 infection was defined as the total positive COVID-19 cases among participants divided by person-weeks at risk. Person-time was calculated from participants’ date of enrollment through March 14, 2021, and ended on the date of receipt of a positive RT-PCR test or date of first vaccination.
The study found that first responders had a higher incidence of COVID-19 infection than health care personnel and other essential workers, even after adjusting for any confounding factors. Crude incidence of COVID-19 infection per 1000 person-weeks was 6.7 for health care personnel, 13.2 for first responders, and 7.4 for other essential workers. In unadjusted models, first responders had 2 times the infection rate as health care personnel (IRRs, 2.01; 95% CI, 1.44-2.79). However, this risk remained elevated in adjusted LASSO models (IRR, 1.60; 95% CI, 1.07-2.38). First responders with the highest risk were corrections, at 16.0%. Notably, risk of infection among essential workers was no different than health care personnel in unadjusted or adjusted models.
Recent studies suggest COVID-19 incidence has decreased in health care settings due to heightened attention to infection prevention procedures. The investigators recommended that first responder communities enact similar measures, and that first responders be prioritized as a high-risk group during the COVID-19 pandemic.