No abstract

Introduction: In March 2020, Australian state and federal governments introduced physical distancing measures alongside widespread testing to combat COVID-19. These measures may decrease people's sexual contacts and thus reduce the transmission of HIV and other sexually transmissible infections (STIs). We investigated the impact of physical distancing measures due to COVID-19 on the sexual behavior of gay and bisexual men in Australia. Methods: Between April 4, 2020, and April 29, 2020, 940 participants in an ongoing cohort study responded to questions to measure changes in sexual behaviors during the COVID-19 pandemic. Men reported the date they become concerned about COVID-19 and whether they engaged in sexual behavior with regular or casual partners or “fuckbuddies” in the 6 months before becoming concerned about COVID-19 (hereafter referred to as “before COVID-19”), and following the date, they become concerned about COVID-19 (hereafter referred to as “since COVID-19”). Before and since COVID-19 was based on individual participants' own perceived date of becoming concerned about COVID-19. Results: The mean age of was 39.9 years (SD: 13.4). Most participants (88.3%) reported sex with other men during the 6 months before COVID-19. Of the 587 men (62.4%) who reported sex with casual partners before COVID-19, 93 (15.8%) continued to do so in the period since COVID-19, representing a relative reduction of 84.2%. Conclusion: Gay and bisexual men in Australia have dramatically reduced their sexual contacts with other men since COVID-19. These behavioral changes will likely result in short-term reductions in new HIV and STI diagnoses. If sexual health screenings are undertaken before resuming sexual activity, this could present a novel opportunity to interrupt chains of HIV and STI transmission.

Considerable concerns relating to the duration of protective immunity against SARS-CoV-2 exist, with evidence of antibody titres declining rapidly after infection and reports of reinfection. Here we monitor the antibody responses against SARS-CoV-2 receptor binding domain (RBD) for up to six months after infection. While antibody titres are maintained, about 13% of the cohort’s neutralising responses return to background. However, encouragingly in a selected subset of 13 participants, 12 have detectable RBD-specific memory B cells and these generally are increasing out to 6 months. Furthermore, we are able to generate monoclonal antibodies with SARS-CoV-2 neutralising capacity from these memory B cells. Overall our study suggests that the loss of neutralising antibodies in plasma may be countered by the maintenance of neutralising capacity in the memory B cell repertoire.

Observed associations between injecting and sexual risk reflect a strong relationship between these practices among GBM. The intersectionality between injecting drug use and sex partying indicates a need to integrate harm reduction interventions for GBM who inject drugs into sexual health services and targeted sexual health interventions into Needle and Syringe Programs.