Epidemiology of transmission among health care workers

Contributed by Dr Rini Bandyopadhyay

HCWs have been particularly hard hit by the COVID-19 pandemic, raising concerns about the effectiveness of personal protective equipment and of nosocomial transmission. Treibel et al demonstrated asymptomatic infection rates among HCWs tracked the London general population infection curve, peaking at 7·1% and falling six-fold over 4 weeks, despite the persistence of a high burden of COVID-19 patients, suggesting that the rate of asymptomatic infection among HCWs reflects general community transmission than in-hospital exposure. Nosocomial transmission can be prevented by appropriate PPE, stringent infection control practices (IPCs) such as universal mask policy, aggressive hand hygiene, and environmental cleaning practices. As the overall epidemic wave recedes, asymptomatic infection among HCWs is low and unlikely to be a major source of transmission. Epidemiological analyses of COVID-19 outbreaks and exposure investigations in healthcare settings have not yet demonstrated airborne transmission of SARS-CoV-2.


  1. Treibel TA, Manisty C, Burton M, et al. COVID-19: PCR screening of asymptomatic health-care workers at London hospital. Lancet. 2020;395(10237):1608-1610