Authors’ response

We thank Kunte et al1 for a critical reading of our article2 and expressing their appreciation for our work on the prophylactic use of hydroxychloroquine (HCQ) in healthcare workers (HCWs). The authors1 found our study design to be suitable and the issues we covered while exploring factors associated with SARS-CoV-2 infection in HCWs appropriate. It also did not escape the notice of the authors of the letter1 that we had underscored the importance of use of personal protective equipment, as a preventive strategy in conjunction with HCQ.

The lower response rate in our study, as has been pointed out, is a known limitation of a telephone-based survey method. It has been seen that while face-to-face surveys are able to cover wider grounds and attain greater representativeness, telephone surveys may need to approach a larger sample of population to compensate for non-participation. However, telephone-based surveys perform better compared to online, mail, or self-reported data collection methods34. We tried to maximize the response rates by reaching out to non-responders by calling them over the phone two additional times, preferably at a different time than the previous call. Worth noting was that the response rates (61% in cases and 68% in controls) in our study were higher compared to the rates encountered in other studies that engaged HCWs in India (paediatricians: 57%)5, Germany (physicians: 56%)6, France (physicians: 59%)7 and the USA (internists: 64%)8.

Our study did not seek to establish the difference in clinical severity of COVID-19 between HCWs taking HCQ prophylaxis and those not taking it. Answering this question would require a differently designed investigation. We find the authors’ proposition of a built-up period of HCQ administration before engaging in clinical care of COVID-19 patients interesting. However, this would need to be based on the data generated through prospective HCQ prophylaxis study. We found associations through case-control investigation, which were indicative of the prophylactic effect of HCQ, and highlighted the need for clinical trials as also suggested by Kunte et al1.