Reduction of secondary transmission of SARS-CoV-2 in households by face mask use, disinfection and social distancing: a cohort study in Beijing, China

Abstract

IntroductionTransmission of COVID-19 within families and close contacts accounts for the majority of epidemic growth. Community mask wearing, hand washing and social distancing are thought to be effective but there is little evidence to inform or support community members on COVID-19 risk reduction within families.MethodsA retrospective cohort study of 335 people in 124 families and with at least one laboratory confirmed COVID-19 case was conducted from 28 February to 27 March 2020, in Beijing, China. The outcome of interest was secondary transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within the family. Characteristics and practices of primary cases, of well family contacts and household hygiene practices were analysed as predictors of secondary transmission.ResultsThe secondary attack rate in families was 23.0% (77/335). Face mask use by the primary case and family contacts before the primary case developed symptoms was 79% effective in reducing transmission (OR=0.21, 95% CI 0.06 to 0.79). Daily use of chlorine or ethanol based disinfectant in households was 77% effective (OR=0.23, 95% CI 0.07 to 0.84). Wearing a mask after illness onset of the primary case was not significantly protective. The risk of household transmission was 18 times higher with frequent daily close contact with the primary case (OR=18.26, 95% CI 3.93 to 84.79), and four times higher if the primary case had diarrhoea (OR=4.10, 95% CI 1.08 to 15.60). Household crowding was not significant.ConclusionThe study confirms the highest risk of transmission prior to symptom onset, and provides the first evidence of the effectiveness of mask use, disinfection and social distancing in preventing COVID-19. We also found evidence of faecal transmission. This can inform guidelines for community prevention in settings of intense COVID-19 epidemics.

Association Between Air Pollution in Lima and the High Incidence of COVID-19: Findings from a Post Hoc Analysis

“…Human pathogenic corona viruses, which include SARS-CoV-2 that is responsible for COVID-19, bind to their target cells through the angiotensin-converting enzyme 2 (ACE2) receptor, which is expressed by epithelial cells of the lung, intestine, kidney, and blood vessels [21]. It is possible that PM 2.5 may induce the elevation of ACE2 activity.…”

Seven days in medicine: 27 May to 2 Jun 2020

“…A study of Chinese families in Beijing, published in BMJ Global Health ,1 found that wearing face masks at home may reduce the spread of covid-19 infection among family members living in the same household, but only before symptoms develop. A face mask worn before symptoms started was 79% effective, and disinfection 77% effective, at stopping the virus from being passed on, the study found.…”

Microbicidal actives with virucidal efficacy against SARS-CoV-2 and other beta- and alpha-coronaviruses: implications for future emerging coronaviruses and other enveloped viruses

“…As anticipated by the guidance provided by the U.S. Centers for Disease Control and Prevention (CDC) 1 , the World Health Organization (WHO) 2,3 , and other regional centers for disease prevention and control, the infection prevention and control (IPAC) strategies of most utility in dealing with the SARS-CoV-2 (COVID- 19) pandemic appear to be social distancing, the wearing of face masks, and the use of microbicides for hand hygiene and for sanitization of high-touch environmental surfaces (HITES) 4 . The latter include, but are not limited to, the toilet, bathroom and kitchen sinks, food preparation surfaces, door knobs, toys, desk tops, coins and paper currency, cell phones and other small electronic devices, automatic teller machines, and shopping carts, etc.)…”