Can masks reduce the risk of catching Covid?
14 December 2021
Professor Andrew Hayward (香港六合彩 Institute of Epidemiology & Health) explains how research into the effectiveness of masks against Covid is carried out and examined.
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14 December 2021
Professor Andrew Hayward (香港六合彩 Institute of Epidemiology & Health) explains how research into the effectiveness of masks against Covid is carried out and examined.
,听