A cluster randomised trial of cloth masks compared with medical masks in XXXX .

@entity1 @entity12767 @entity683 @entity281 @entity1729 @entity1576
OBJECTIVE: The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital @entity12767 ( @entity12767 ). The null hypothesis is that there is no difference between medical masks and cloth masks. SETTING: 14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam. @entity1 : 1607 hospital @entity12767 aged >= 18   years working full-time in selected high-risk wards. INTERVENTION: Hospital wards were randomised to: medical masks, cloth masks or a control group (usual practice, which included mask wearing). @entity1 used the mask on every shift for 4 consecutive weeks. MAIN OUTCOME MEASURE: Clinical @entity1576 (CRI), @entity683 ( @entity683 ) and laboratory-confirmed @entity1729 . RESULTS: The rates of all @entity281 outcomes were highest in the cloth mask arm, with the rate of @entity683 statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of @entity683 compared with the control arm. An analysis by mask use showed @entity683 (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%. CONCLUSIONS: This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of @entity281 . Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for @entity12767 , particularly in high-risk situations, and guidelines need to be updated. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry: ACTRN12610000887077.
