Risk of COVID-19 Infection in the healthcare workforce
Because of how COVID-19 is spread and the fact that individuals who contract the illness often go to emergency rooms, hospitals, and other healthcare settings, the healthcare workforce is at a greater risk of contracting COVID-19 than the general population.
Approximately 4.62% of COVID-19 cases in the U.S. have been health care workers (HCWs). However, due to the shortage of available tests and current testing capacities, the current number of infected HCWs is likely higher. In states with more complete data, HCWs accounted for up to 11% of COVID-19 cases.
More than half of HCWs with COVID were exposed by treating affected patients or coming into contact with infected individuals at the healthcare facility.
We also know HCWs are disproportionately affected from previous outbreaks of related respiratory illnesses such as MERS.
In previous outbreaks in other countries between, 18-30% of the total cases were HCWs who had contracted the illness in healthcare settings.
Global HCW COVID Infection Rates
The global rates of HCW COVID infections are disproportionate:
Health workers represent less than 3% of the population in most countries and less than 2% in almost all low- and middle-income countries.
Health-care workers account for 1 in 7 coronavirus cases recorded by the World Health Organization.
Globally, around 14% of COVID-19 cases reported to WHO are among health workers, and in some countries it’s as much as 35%.
USA HCW COVID Infection Rates
Health-care workers accounted for 11-16% of COVID-19 cases during the first surge of infections in the United States.
Contributing factors
The greater levels of testing among health-care workers contributes to the higher known infection rates. Increased testing allows for more infections to be identified , but testing does not cause more infections.
The high risk work environment combined with a lack of appropriate PPE is a substantial factor in infection rates.
Why Healthcare Workers get COVID-19
from Zabarsky et al, American Journal of Infection Control, August 11
- Whenever we let our guard down, we are at risk. In other words, even though we think we are taking precautions, there are everyday situations where we become careless.
- Not only patients, but also colleagues must be considered a virus carrier.
- Pre-symptomatic and asymptomatic colleagues spread infections.
- Interacting with colleagues with mask down can be potentially dangerous.
- Spread also happens in non-patient care areas: break rooms, nursing stations, cafeteria.
- Having lunch together involves not only lowering of mask, but also conversation (generates aerosols) and prolonged exposure time (sitting together at a table).
- Infections occurred more in non-COVID wards, where people were less alert.
- There were no infections in ICU or COVID wards (everyone was alert).
- Patients with atypical symptoms and delayed diagnosis contributed to HCW infections.
- When more testing became available, there was less infection (people were identified early).
- HCW can get infected outside the workplace (14% cases); i.e. from the family or community.
- In 50% cases, no source was identified.
Meta-analysis of COVID-19 cases among HCW
A meta analysis reviewed 45 global studies that included more than 44,879 health care workers.
The studies reviewed measured the prevalence of COVID-19 in HCW by using either RT-PCR or a serum antibodies assay.
Among those studies, the prevalence of COVID-19 cases by testing method were:
PCR (11%)
Antibody testing (5%)
A significant proportion of HCW are positive for COVID-19 while asymptomatic.
Eight studies examined the prevalence of asymptomatic cases.
The pooled prevalence of asymptomatic carriers among RT-PCR positive HCW was 46%.
Over 4 in 10 health care workers who tested positive for COVID-19 didn’t have symptoms, which means they could unknowingly spread the disease to co-workers, patients, and family members.
Take Home Messages
HCW represent a population with a significant burden from COVID-19.
HCW exhibit a high prevalence of SARS-CoV-2 infection, with a significant proportion of the infected HCW being asymptomatic carriers.
This condition favors silent transmission both in clinical and in community contexts if adequate preventive measures and other standard procedures are not implemented.
References
Cases in the U.S. | CDC. Published May 30, 2020. Accessed May 30, 2020.
Characteristics of Health Care Personnel with COVID-19 United States, February 12-April 9, 2020. MMWR Morb Mortal Wkly Rep 2020;69:477–481.
Cowling BJ, Park M, Fang VJ, Wu P, Leung GM, Wu JT. Preliminary epidemiological assessment of MERS-CoV outbreak in South Korea, May to June 2015 [published correction appears in Euro Surveill. 2015;20(26). pii: 21175]. Euro Surveill. 2015;20(25):7–13. Published 2015 Jun 25. doi:10.2807/1560-7917.es2015.20.25.21163
Glenza J. US medical workers self-isolate amid fears of bringing coronavirus home. The Guardian. Published March 19, 2020. Accessed April 21, 2020.
Gomez-Ochoa, S.A., Franco, O.H., Rojas, L.Z., Raguindin, P.F., Roa-DÃaz, Z.M., Wyssmann, B.M., Guevara, S.L.R., EcheverrÃa, L.E., Glisic, M. and Muka, T., 2020. COVID-19 in Healthcare Workers: A Living Systematic Review and Meta-analysis of Prevalence, Risk Factors, Clinical Characteristics, and Outcomes. American journal of epidemiology.
Hunter JC, Nguyen D, Aden B, et al. Transmission of Middle East Respiratory Syndrome Coronavirus Infections in Healthcare Settings, Abu Dhabi. Emerg Infect Dis. 2016;22(4):647–656. doi:10.3201/eid2204.151615
Washington Post, “Health-care workers make up 1 in 7 covid-19 cases recorded globally, WHO says“
Zabarsky, T.F., Bhullar, D., Silva, S.Y., Mana, T.S., Ertle, M.T., Navas, M.E. and Donskey, C.J., 2020. What are the sources of exposure in healthcare personnel with coronavirus disease 2019 infection?. American Journal of Infection Control.