1:Ĭurrent and retrospective concurrency estimates among men aged 15–49 years.(a) Point prevalence of concurrency on the basis of number of current partners (left most square) and retrospective cutoffs for male respondents aged 15–49 years.

We believe this bias is more likely due to poor recall leading to underreporting or misreporting details of sexual behaviour so long before the interview. Estimates of concurrency relating to the period 7–11 months before the interview are also lower, which could possibly be due to the censoring of the survey instrument to only three partners in the past year, although this is unlikely to have exerted substantial bias because only 0.2% of men reported having more than three partners in the past year who were not already classified as having concurrent partners. Closer to the interview, the estimate of concurrency is lower, which could be because respondents have not recently had sex with a long-term partner or because of reluctance to report recently initiated or dissolved partnerships. At about 4–6 months, the estimate stabilizes, which confirms 6 months to be within the optimal measurement period. Estimates are aggregated over the six data collection rounds from 2005 through 2010, for a total of 26 088 observations on 13 785 men.įigure 1(a) shows the estimates of concurrency at each retrospective month. Thus, results presented are for men aged 15–49 years, who were resident at the time of the interview and completed the sexual behaviour survey. In each round, less than 0.4% of women reported concurrency. We use these data to calculate the ‘current’ point prevalence of concurrency based on the reported number of ongoing sexual partners at the time of the survey and the ‘retrospective’ point prevalence of concurrency for each month from 1 to 11 months before the interview. First, are you still in a sexual relationship with (partner)? Second, how long were you/have you been sexually involved with this partner? And third, when was the last time you had sex with (partner)? The latter two questions are answered as duration before the interview in days, weeks, months, or years at the discretion of the respondent. These surveys include questions about the three most recent sexual partners in the past year, including the three questions required to calculate the recommended concurrency indicator. Since 2005, all adults (age 15 years and older) in the surveillance area have been invited every year to complete a face-to-face general health survey. We use sexual behaviour survey data collected in a high HIV prevalence rural population in KwaZulu-Natal, South Africa to explore the effect of different choices on the accuracy of the indicator. An optimal retrospective period would minimize these downward biases, but the recommendation to use a period of 6 months was made without the benefit of empirical data. For a short retrospective period, the indicator might not detect concurrent partnerships in which the respondent has not recently had sex with a long-term partner, but too long a period might incur censoring bias by only collecting the three most recent partners. Particularly debated was the decision to estimate concurrency at a retrospective point before the interview rather than at the time of the interview using the reported number of current ongoing partnerships. A consensus indicator for concurrency allows comparison across populations and reproducible research about the association between concurrency and HIV, but uncertainties remain about the indicator and its calculation. The UNAIDS Reference Group on Estimates, Modelling, and Projections recently recommended that the primary indicator for measuring concurrent sexual partnerships be the point prevalence of concurrent partnerships 6 months before the interview and recommended nine survey questions to calculate this indicator.

Unpacking 2012