Prevention of sexual transmission of mpox: a systematic review and qualitative evidence synthesis of approaches.

Background: The ongoing multi-country mpox outbreak in previously unaffected countries is primarily affecting sexual networks of men who have sex with men. Evidence is needed on the effectiveness of recommended preventive interventions. To inform WHO guidelines, a systematic review and qualitative evidence synthesis were conducted on mpox preventive behavioural interventions to reduce: (i) sexual acquisition; (ii) onward sexual transmission from confirmed/probable cases; and (iii) utility of asymptomatic testing.

Methods: Medline, EMBASE, PubMed, Cochrane and WHO trial databases, grey literature and conferences were searched for English-language primary research published since 1 January 2022. A reviewer team performed screening, data extraction and bias assessment. A qualitative thematic synthesis explored views and experiences of engagement in prevention in individuals at increased risk.

Results: There were 16 studies: 1 on contact-tracing, 2 on sexual behaviour, and 13 on asymptomatic testing. Although MPXV was detected in varying proportions of samples (0.17%-6.5%), the testing studies provide insufficient evidence to fully evaluate this strategy. For the qualitative evidence synthesis, four studies evaluated the experiences of most affected communities. Preferences about preventive interventions were shaped by: mpox information; the diversity of sexual practices; accessibility and quality of mpox testing and care; and perceived cost to wellbeing.

Conclusions: Evidence on the effectiveness of interventions to prevent the sexual transmission of mpox remains scarce. Limited qualitative evidence on values and preferences provides insight into factors influencing intervention acceptability. Given global and local inequities in access to vaccines and treatment, further research is needed to establish the effectiveness of additional interventions.