A examine carried out by scientists from the US Centers for Disease Control and Prevention (CDC) signifies that decreasing one-time sexual partnerships amongst homosexual, bisexual, and different men who’ve intercourse with men can considerably reduce the transmission of the monkeypox virus. The analysis is revealed within the CDC’s Morbidity and Mortality Weekly Report (MMWR).
Study: Modeling the Impact of Sexual Networks in the Transmission of Monkeypox virus Among Gay, Bisexual, and Other Men Who Have Sex With Men — United States, 2022. Image Credit: NIAID
Background
Global outbreaks of monkeypox infections in 2022 have indicated that sexual contact is the first route of monkeypox transmission amongst men with a number of male intercourse companions.
Some latest survey reviews have revealed that men who’ve intercourse with men (MSM) have adopted sure measures to shield themselves and their companions from monkeypox an infection. The commonest measure is decreasing one-time sexual partnerships.
Various fashions of sexual an infection transmission developed by the CDC have beforehand been used to examine the unfold of human immunodeficiency virus (HIV) and gonorrhea within the US. In the present examine, these fashions had been used to examine the transmission dynamics of monkeypox an infection amongst MSM.
Study design
The dynamic community fashions simulated by CDC characterize sexual behaviors between MSM. In these fashions, men had been predicted to have varied sorts of sexual relationships, together with major, causal, or one-time partnerships.
According to the mannequin simulations, men may need zero or one major sexual partnership at a time that lasted on common 477 days, or zero, one, or two informal partnerships at a time that lasted for on common 166 days. In addition, men may need one-time partnerships that lasted for in the future.
Between 2016 and 2019, CDC collected knowledge from MSM, who reported the quantity, sort, and length of their present sexual partnerships. This knowledge was used to develop six classes of sexual exercise, which differ of their price of one-time partnership formation.
Two circumstances of monkeypox transmission had been simulated whereby ten extremely lively circumstances had been launched to a inhabitants of 10,000 MSM. Both decrease and larger transmission charges had been thought of by adjusting transmission chance per act. In the decrease transmission situation, monkeypox was assumed to infect 15% of MSM. In the upper transmission situation, the virus was anticipated to infect 25% of MSM.
The discount within the share of contaminated MSM was estimated at baseline (time of viral entry within the inhabitants) and beneath a situation whereby MSM decreased the frequency of one-time partnerships by 40% after 2.5 months of viral entry within the inhabitants. This situation was created primarily based on the observations made in latest surveys.
Modeled quantity* of new infections every day by decrease† and larger§ transmission eventualities and sort of partnership over the course of a monkeypox outbreak amongst men who’ve intercourse with men, by time since importation of 10 excessive exercise circumstances — United States, 2022
Important observations
The predictions made by the fashions revealed that MSM with multiple accomplice prior to now three weeks have a 2 – 7 instances larger risk of contracting monkeypox an infection in contrast to these with just one accomplice.
Considering the decrease transmission situation, MSM within the highest class of sexual exercise have a 3.6 instances larger risk of contracting monkeypox an infection in contrast to these with just one accomplice prior to now three weeks. In the upper transmission situation, these men had been predicted to have a 7 instances larger risk of contracting the an infection.
A disproportionate impact of one-time partnerships was noticed on viral transmission. In the fashions, one-time partnerships represented 3% of the overall day by day partnerships and 16% of the sexual contacts on a given day. However, relying on the speed of transmission, these partnerships accounted for 46% to 54% of viral transmission.
In the decrease transmission situation, one-time, informal, and major partnerships had been related to 54%, 33%, and 12% of viral transmission, respectively. In the upper transmission situation, about 45%, 38% and 15% of transmissions had been brought on by one-time, informal, and major partnerships, respectively.
Notably, the mannequin predicted {that a} 40% discount in one-time partnerships might lower the proportion of contaminated MSM by 20% to 31%. This impact was extra important within the decrease transmission situation. Furthermore, the discount in one-time partnerships delayed the timing of accumulating 10% an infection by 150 days.
Study significance
This CDC examine highlights the importance of decreasing one-time partnerships in reducing the risk of monkeypox unfold amongst MSM. Reducing the quantity of one-time or informal intercourse companions can considerably management monkeypox outbreaks in non-endemic nations.
The scientists counsel that the noticed impact may very well be elevated additional by implementing extra management measures, equivalent to vaccination, testing, and contact tracing.
