New modeling data by the Centers for Disease Control and Prevention (CDC) show that reducing the number of one-time partners in sex between men may be a key factor in slowing the spread of monkeypox.
Ian Spicknall, PhD, with the CDC Monkeypox Emergency Response Team, led the modeling study published Friday in the Morbidity and Mortality Weekly Report (MMWR ).
Researchers found that men who have sex with men (MSM) who had more than one partner in the past 3 weeks had 1.8 to 6.9 times the risk for monkeypox infection compared with those who had one partner in the past 3 weeks, depending on the transmission scenario.
The percentage of such partnerships is small — one-time partnerships represent less than 3% of daily partnerships and 16% of sex between men each day, the authors note. But one-time partnerships accounted for 50% of all monkeypox transmissions.
The model indicates that reducing such partnerships has a large effect. The authors write, “a 40% decrease in one-time partnerships yielded a 20%-31% reduction in the percentage of MSM infected and a delay in the spread of the outbreak.”
“If decreasing one-time partnerships were combined with additional mitigation measures such as vaccination or shorter time from symptom onset to testing and treatment, this effect would be higher,” the authors write.
Peter Chin-Hong, MD, an infectious disease specialist with University of California, San Francisco, told Medscape Medical News, “I think [the study] corroborates what we suspected biologically based on how this outbreak is going. It gives us good insight into how we can tailor messages.”
“The value of the study is to put a number on it,” he said, which can help public health officials and people in the community know where changes make the most impact. Chin-Hong was not involved in the study.
Since late May, the US has recorded nearly 17,000 monkeypox cases. The outbreak is largely being transmitted among gay and bisexual men.
Reduction in Risky Behaviors
Chin-Hong added that there is evidence that partner behavior is already changing among MSM and that people in the community are reducing the number of sexual partners and reducing activity on dating apps such as Grindr.
