Received: 20 October 2020
Accepted: 26 May 2021
First Online: 7 June 2021
: The study was reviewed and approved by the Local Ethics Committee at the North-Western State Medical University named after I.I. Mechnikov, St. Petersburg, Russia (№4 of May 27, 2020). Written informed consent was obtained from all participants in the study. A placebo group was not approved for this pilot study by the Local Ethics Committee due to ethical issues. It was decided that it was not ethical to treat any individuals at high risk for SARS-CoV-2 infection with a placebo during the COVID-19 pandemic. The data for the comparison group were collected anonymously in accordance with local routine COVID-19 surveillance reports. NWSMU made all decisions regarding the study design and implementation. The Ministry of Health of the Russian Federation and the Federal Supervision Service for Healthcare provided oversight for the study in accordance with the framework of the Government Decree of the Russian Federation 441 of April 3, 2020.
: Not applicable.
: The authors declare that they have no competing interests.