(P205) Demographic factors and sexual history of people diagnosed with mpox and people vaccinated against mpox at a central London sexual health and HIV clinic

Background
Mpox, formerly known as monkeypox, was first reported over 50 years ago. Unlike previous outbreaks, the 2022 outbreak predominantly has affected men-who-have-sex-with-men (MSM) in high-income countries. In response, first doses of the Modified Vaccinia Ankara (MVA) smallpox vaccine were offered to MSM deemed most at risk based on sexual history. We describe the demographic and other characteristics of people diagnosed with mpox and recipients of MVA vaccination in our clinic.



Methods

Data was extracted from electronic health records of people diagnosed with mpox and those receiving a first dose of MVA vaccination at a London outpatient clinic in May-August 2022. Demographic and clinical data was analysed, and proportions compared between groups. Ethnicity data is reported using UK Office for National Statistics categories.



Results

A total of 3,507 people received first dose MVA vaccination, and 163 people tested PCR positive for mpox in May-August 2022. All people diagnosed with mpox were male; median age 38 years (IQR 32-47). 99.1% of those vaccinated were male; median age 36 years (IQR 31-46). Nine individuals received MVA vaccination prior to testing mpox positive; median time between vaccination and positive mpox test was 10 days (IQR 4-12.5). Compared to those who received vaccination, people with mpox had higher proportions born outside the UK (61.1% vs 48.3%, proportions test p=0.009). Of people with mpox with a documented sexual history, 4% reported female only sexual partners in the previous three months. The majority (54.2%) of MSM with mpox reported fewer than five male sexual partners in the previous three months, with 15% reporting only one. 146/163 (89.6%) of people with mpox had concurrent testing for other sexually transmitted infections (STI); 41 (28.1%) tested positive for a concurrent STI, with gonorrhoea the most common (16/41).



Conclusion

The characteristics of MVA vaccination recipients were similar to those presenting with mpox, although lower proportions from immigrant backgrounds received vaccination. Restriction of vaccination to MSM with five or more recent sexual partners may miss individuals at risk of infection. People with suspected mpox should be offered STI testing. Vaccination should be offered to all people at risk of mpox.