Author's reply.

We thank Tuech et al. and Dr. Ross for their letters in response to our recent study [1]. At the very beginning of the epidemic, we encountered some patients who had no symptoms before surgery but quickly developed COVID-19 pneumonia after surgery. During the period of the research, the participating hospitals performed approximately 15,000 elective surgeries. Our focus was to report those we believe and confident that the surgeries were performed during incubation period. Thus, any infection long after surgery (say, 10 to 14 days after surgery) or those who contacted with confirmed cases of COVID-19 after surgery (such as the 3 excluded patients) were excluded. Additionally, we cannot exclude the possibility that there may be someone who got infected and performed surgery but maintained asymptomatic, despite this might be rare. Therefore, the rate of 0.22% etc. as the authors estimated could only be the rate of unintentional surgery that activated latent infection.

As for the number of patients in each group (surgical difficulties), we have presented the details of types of surgery and grading of surgical difficulty in Table 1 and Table 2 in our published article [1]. We appreciate the authors’ suggestion of providing detailed rates of infection and mortality etc. for all surgical patients at that time. However, this was not the scope of our original study, and also exact detailed information couldn't be provided due to the lack of additional ethical approval at this point. We advise that strict protective procedures be followed [2,3] as asymptomatic COVID-19 is also contagious.

Declaration of Competing Interest

None.