Moderate frequency handwashing, six to 10 times a day, is linked to a lower risk for seasonal coronavirus infection, according to a study awaiting peer review in Wellcome Open Research.
UK researchers investigated whether hand hygiene impacted the risk of acquiring seasonal coronavirus infection to determine if it may also mitigate the spread of COVID-19 in community settings, as is believed.
Data were drawn from three successive winter cohorts (2006-2009) of the England-wide Flu Watch study. The majority of participants (almost 80%) were adults over 16 years of age. Participants (n=1633) provided baseline estimates of hand hygiene behaviour.
Frequency of daily handwashing was subsequently categorised as low (not more than five times daily), moderate (six to 10 times daily) or high (>10 times daily) guided by literature around influenza-like illness in Western community settings.
Coronavirus infections were identified from nasal swabs using reverse transcription polymerase chain reaction. Poisson mixed models estimated the effect of hand hygiene on personal risk for coronavirus illness, both un-adjusted and adjusted for confounding by age and health care worker status.
Moderate-frequency handwashing (six to 10 times per day) predicted a lower personal risk for coronavirus infection (adjusted incidence rate ratio (aIRR), 0.64; P=.04). There was no evidence for a dose-response effect of handwashing, with results for higher levels of hand hygiene (>10 times per day) being not significant (aIRR, 0.83; P=.42).
The findings support clear public health messaging around the protective effects of handwashing in the context of the current COVID-19 pandemic, the authors said.