Minimal Coital Dilution in Accra, Ghana

Abstract

Background Coital dilution, the reduction in the coital frequency per partner when an additional ongoing partner is added, may reduce the transmission potential of partnership concurrency for HIV and other sexually transmitted infections. Empirical estimates of dilution, especially dilution of sexual acts unprotected by condoms, are needed to inform prevention research. Methods Sexually active adults in Accra, Ghana were recruited in a multi-stage household probability sample. Degree (number of ongoing partners), total acts, and unprotected acts were measured retrospectively for each month in the past year through an event-history calendar. Random effects negative binomial models estimated the association between degree and coital frequency. Results Compared to person-months with a single partner (monogamy), 2.06 times as many total acts and 1.94 times as many unprotected acts occurred in months with 2 partners. In months with 3 partners, 2.90 times as many total acts and 2.39 times as many unprotected acts occurred compared to monogamous months. Total acts but not unprotected acts also declined with partnership duration. Conclusions No dilution was observed for total acts with up to three concurrent partners, but a small amount of dilution was observed for unprotected acts for months with multiple concurrencies. This suggests moderate selective condom use in months with multiple concurrencies. The implications of the observed dilution for future HIV transmission must be investigated with mathematical models.

Frequency and impact of suboptimal immune recovery on first-line antiretroviral therapy within the International Epidemiologic Databases to Evaluate AIDS in East Africa

“…Other studies have shown similar rates of CD4 + cell counts persisting below 200 cells/μl, 350 and 500 cells/μl, and a continued high rate of clinical events during ART [32–34,37,38]. Even in settings where there is routine monitoring of viral load, data show that although the majority of those who are virologically suppressed achieve good immune recovery, up to 40% still exhibit SO-IR [39,40].…”

“…A variety of different definitions have been used in clinical trials [33,34], observational cohorts [31,32], pathogenesis studies [19,35] to define suboptimal recovery. In this analysis, we defined SO-IR as failure to attain three different CD4 + cell count thresholds during the first 5 years of first-line antiretroviral therapy: 200 cells/μl (SO-IR200), below which individuals remain at particular risk of life-threatening opportunistic infections [22,23]; 350 cells/μl (SO-IR350) – the recommended threshold for ART initiation in the WHO 2010 guidelines [7] and 500 cells/μl (SO-IR500) – the recommended threshold for ART initiation in WHO 2013 guidelines [9].…”

“…These include a magnitude of CD4 + cell count increase of less than 50 cells/μl after 6 months [29], or less than 100 cells/μl after 12 months [12,30], and an absolute CD4 + cell count remaining below 200 cells/μl after 24 months [31,32], or below 500 cells/μl after 60 months [33] as well as variations in longitudinal analyses [34]. Understanding the proportion of patients who fail to attain CD4 + cell count levels above 200, 350 and 500 cells/μl has important programmatic implications.…”

Effectiveness of combination packages for HIV-1 prevention in sub-Saharan Africa depends on partnership network structure: a mathematical modelling study

“…Degree terms were stratified by sex, as men exhibited both higher mean degree and prevalence of concurrency. 12 A parametrical term was used to model sex-asymmetry in age homophily typical of heterosexual partners in SSA: persons tended to select partners similar in age, but asymmetrically, as men were older than their female partners (an average 5.4 years in MHG).…”

“…This translated to a reduction in the mean duration by 0.9 years; the expected number of lifetime partners between the MHG estimates (9.6) and simulations after this adjustment (10.1) were similar. 12 …”