Hand and Respiratory Hygiene Practices and the Risk and Transmission of Human Coronavirus Infections in a UK Community Cohort

Background: Respiratory and hand hygiene may mitigate the spread of COVID-19 in community settings; however, empirical evidence is limited. Given reports of similar transmission mechanisms for COVID-19 and seasonal coronaviruses, we investigated whether hand and respiratory hygiene impacted the risk of acquiring or transmitting seasonal coronavirus infections. Methods: Data were drawn from three successive winter cohorts (2006-2009) of the England-wide Flu Watch study. Participants (n=1605) completed baseline surveys of hand and respiratory hygiene practices. Coronavirus infections were identified from nasal swabs using RT-PCR. Poisson mixed models estimated the effect of hand hygiene on personal risk of coronavirus illness overall and following household exposure, and the effect of respiratory and hand hygiene practices on onwards transmission by household index cases. All models were adjusted for confounding by age. Findings: Moderate-frequency handwashing predicted a lower personal risk of coronavirus infection (age-adjusted incidence rate ratio (aIRR) =0·65, p=0.03) although results for even higher levels of hand hygiene were not significant. For household index cases, overall practice of respiratory hygiene (aIRR =0·61, p=0.01) and handwashing after coughing or sneezing (aIRR = 0·35, p=0.02) were associated with lower risk of onwards transmission. Interpretation: This is the first empirical evidence that respiratory hygiene practices including handwashing after coughing or sneezing can reduce household transmission and regular handwashing can reduce personal risk of acquiring seasonal coronavirus. These findings support clear public health messaging around respiratory hygiene, targeted at those with respiratory symptoms, to protect others, and of the value of regular hand washing, regardless of symptoms, for personal protection. Funding Statement: The Flu Watch study received funding from the Medical Research Council (MRC) and the Wellcome Trust (MR/K006584/1). S.B. is supported by an MRC doctoral studentship (MR/N013867/1). Declaration of Interests: ACH serves on the UK New and Emerging Respiratory Virus Threats Advisory Group. AMJ was a Governor of Wellcome Trust from 2011-18 and is Chair of the Committee for Strategic Coordination for Health of the Public Research. The other authors declare no competing interests. Ethics Approval Statement: The protocol was approved by the Oxford Multi-Centre Research Ethics Committee (06/Q1604/103).