Published on in Vol 22, No 6 (2020): June
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/15970, first published
.
1 School of Population Health & Environmental Sciences, King's College London, London, United Kingdom
2 SH:24, London, United Kingdom
3 Department of Sexual Health and HIV, King's College Hospital, London, United Kingdom