Reply to "Does hand hygiene reduce SARS-CoV-2 transmission?"

Dear Editor,

We would like to thank Dr. Chao Yang’s comments to our article [1].

We would like to emphasize that both face masking and hand hygiene are important in preventing the transmission of coronavirus disease 2019 (COVID-19) and are not mutually exclusive [2]. According to the report of the WHO-China joint mission on COVID-19, COVID-19 is transmitted via droplets and fomites during close unprotected contact between an infector and infectee. Airborne spread has not been reported for COVID-19, and it is not believed to be a major driver based on currently available evidence [3]. A recent study by Ong et al. obtained air and surface environmental samples from isolation wards of COVID-19 patients and found the air samples to be negative of SARS-CoV-2, but positive samples were found on multiple environmental surfaces [4]. These sites included the table, bed rail, locker, chair, light switches, door, window, and surfaces in the toilet including the toilet bowl, sink, and door handle. Stool samples were also positive for SARS-CoV-2. Otter and his colleagues found that SARS-CoV and other coronaviruses can survive on environmental surfaces up to 6 days [5]. Furthermore, it is not uncommon that healthcare workers, including ophthalmologists, may overlook the importance of hand hygiene, as frequent face touching is notoriously common that even medical students touched their faces 23 times per hour and 44% of those touches involved contact with mucous membranes [6].

Based on the above evidence, hand hygiene, together with appropriate personal protective equipment, is of utmost importance to break the cycle of touching contaminated environmental surfaces and subsequent inoculation of the virus through touching mucous membranes, thus reducing the risk of transmission of COVID-19.