Authors' response.

We thank the author of the letter for a critical reading of our article1. Our study was conducted to generate evidence to inform and, if needed, review policy responses particularly with regard to the use of chemoprophylaxis by healthcare workers against COVID-19. While acknowledging the shortcoming in recruiting cases and controls based on the calculated sample size, we would like to underline that the response rate in our study has been higher compared to the other studies, following a similar methodology, both in India and abroad2345. Registry-based recruitment and telephonic surveys are known to face the hurdle of non-participation. Therefore, in order to improve the response rate, we followed several strategies, such as multiple call attempts, targeted call times and training interviewers678.

While we are aware that the article by Mehra et al9, used as a reference in our publication, has been retracted, we would like to highlight the fact that our article was published in May 2020, before the retraction notice was issued on June 5, 2020. The Lancet editors published an expression of concern about the article by Mehra et al9 on June 3, 202010. Further, the topic of the now retracted study was treatment of COVID-19 cases, whereas the ambit of our study was pre-exposure prophylaxis against SARS-CoV-2. The two were very different contexts.