Staged HIV transmission and treatment in a dynamic model with long-term partnerships

Abstract

The transmission dynamics of HIV are closely tied to the duration and overlap of sexual partnerships. We develop an autonomous population model that can account for the possibilities of an infection from either a casual sexual partner or a long-term partner who was either infected at the start of the partnership or has been newly infected since the onset of the partnership. The impact of the long-term partnerships on the rate of infection is captured by calculating the expected values of the rate of infection from these extended contacts. The model includes three stages of infectiousness: acute, chronic, and virally suppressed. We calculate HIV incidence and the fraction of new infections attributed to casual contacts and long-term partnerships allowing for variability in condom usage, the effect of achieving and maintaining viral suppression, and early intervention by beginning HAART during the acute phase of infection. We present our results using data on MSM HIV transmission from the CDC in the U.S. While the acute stage is the most infectious, the majority of the new infections will be transmitted by long-term partners in the chronic stage when condom use is infrequent as is common in long-term relationships. Time series analysis of the solution, as well as parameter sensitivity analysis, are used to determine effective intervention strategies.

Impact of increased diagnosis for early HIV infection and immediate antiretroviral treatment initiation on HIV transmission among men who have sex with men in the Netherlands

“…Similar findings, in the context of the general MSM population in the USA, were shown in another modeling study where the increase in early HIV diagnosis and ART uptake led to notable reductions in the number of new HIV infections and a subsequent decrease in HIV prevalence over a two-decade span [13]. Moreover, a study focusing on MSM in San Francisco highlighted the importance of quicker ART initiation, showing that reducing the time from diagnosis to treatment initiation could significantly decrease the number of new HIV infections [14].…”

“…A study set in Peru, a region with a notably high rate of new HIV infections, projected that a significant number of new HIV infections can be prevented over 20 years by increasing the diagnosis rate and initiating ART early in individuals with early HIV infection and initiating ART [12]. Similar findings, in the context of the general MSM population in the USA, were shown in another modeling study where the increase in early HIV diagnosis and ART uptake led to notable reductions in the number of new HIV infections and a subsequent decrease in HIV prevalence over a two-decade span [13]. Moreover, a study focusing on MSM in San Francisco highlighted the importance of quicker ART initiation, showing that reducing the time from diagnosis to treatment initiation could significantly decrease the number of new HIV infections [14].…”