Sampling design and recruitment

Each round for the IBBSS utilized respondent driven sampling provided towards the concealed nature of MSM and therefore permits contrast between and across rounds. Respondent driven sampling (RDS) happens to be described at length in past studies 22, 23. Quickly, RDS is really a modified chain referral non-random sampling method of recruitment that adjusts for the non-randomness making use of a mathematical model that loads each sample recruited 23. Inclusion criteria had been male aged 16 years and above with a brief history of dental and/or anal contact that is sexual another guy when you look at the six months before the study. Known MSM, designated as “seeds” began the chain associated with the recommendation use and network vouchers to recruit their peers in to the study. Ten seeds had been chosen for every round and seeds had been diversified by age, academic status and socioeconomic status. To prevent an over-representation of MSM with comparable characteristics, vouchers limited by three per recruit was utilized 23, 24. In addition, in order to avoid perform enrollment, only 1 screener ended up being utilized, only 1 individual ended up being authorized to reimburse MSM who had effectively recruited their peers and just one location ended up being utilized. Each voucher had been yielded and redeemable N500 approx. $3 USD being a motivation for participating, with an extra N500 provided to a recruit for every effective participant that is additional. Total payment had been restricted to a compensation that is maximum of approximately $12 USD. Test size when it comes to 2007 IBBSS ended up being projected according to an thought HIV prevalence of 15%, a design effectation of 2.0 and standard of accuracy of 0.05. For the 2010 and 2014 IBBSS, test size had been projected to identify a 10% differ from the round that is subsequent.

Data collection

Structured close-ended interviewer administered questionnaires elicited information on socio-demographic traits, kind of intercourse partners and intimate danger actions. Interviews had been carried out in MSM organizations that are friendly in all the research states. Transactional sex had been evaluated both with feminine and male lovers. Kind of rectal intercourse practiced ended up being classified as “insertive penile intercourse” or “receptive penile intercourse” into the past a few months. HIV danger perception had been examined by asking MSM you are at risk of infection with HIV? ” with response options being “yes or no”“do you feel. Consistent condom use with sexual lovers during transactional and sex that is non-transactional evaluated by asking the concerns “how frequently did you or your male partner work with a condom every time you had sex within the last 6 months? ” while condom usage at final intercourse had been evaluated by the concern “the last time you’d anal sex did you or your partner make use of a condom? ”. Transactional sex had been evaluated by asking “have you received gift or money in exchange for intercourse within the last a few months? ” Written permission ended up being acquired from all individuals both for behavioural and biological aspects of the study.

Laboratory testing

Detection of HIV during all of the studies had been regularly carried out by fast test utilizing whole bloodstream samples acquired from the hand prick. In line with the HIV that is national testing, a synchronous algorithm of Determine (Alere healthcare, United States Of America) and Unigold (Trinity Biotech, Plc, Bray, Ireland) ended up being utilized to spot HIV sero-positivity while status of discordant tests had been verified by using Stat Pak (Chembio Diagnostic techniques, ny, United States Of America).

Information administration and analysis

Data from each research state were entered CS that is centrally using Pro 3.2 and 25% of questionnaires underwent double-data entry to make sure information quality. Behavioural and biological information had been connected by research identification that is unique for every participant. Information from each round had been merged and analyzed STATA that is using 14.0 Corporation). Descriptive statistics of demographic, behavioural, and biological factors ended up being conducted. The Cochran-Armitage Chi Square trend test ended up being utilized to compare differences when considering categorical factors across various rounds of IBBSS, even though the Kruskal-Wallis test ended up being used to compare variations in constant factors across various rounds of IBBSS. To determine associations between HIV and predictor factors (Tables), bivariate regression that is logistic had been carried out with p value ?0•2 designated as the cutoff for addition in multivariate logistic regression models. Factors were retained when they attained a p value ?0•05 within the analysis that is multivariate. The predictor factors had been predicated on information from literary works that revealed a link involving the factors and HIV.


Table 1 highlights the sociodemographic information of MSM throughout the three rounds associated with IBBSS. A complete of 897, 1545 and 3611 MSM had been surveyed in 2007, 2010 and 2014 correspondingly. Most of the participants had been aged 20–24 years in 2007 (61%) and 2014 (46%), whilst in 2010, almost half (47%) regarding the participants were 25 years or older. Over 85% associated with the respondents had never ever hitched in each round associated with study. Most of the participants had finished at the very least level that is secondary, and also this ended up being greatest among respondents in 2007 with 63per cent followed closely by participants in 2014 (55%).

Intimate danger Behaviours

The median wide range of insertive anal lovers ended up being constant between 2007 and 2010 with about 50% of this participants insertive that is reporting sex (IAS) with at the least two lovers interquartile range (IQR 1–4) within the last a few months. For receptive anal sex (RAS), a median of two partners that are sexual reported in 2007 although it ended up being one partner both in 2010 and 2014. Overall, about a 3rd had engaged in transactional intercourse in 2007 (95% confidence period (CI): 30–36%) and 2014 (32–35%), whilst it had been about two-fifths this season (36–41%). Consistent condom use, whenever intercourse had been offered increased steadily from 35% (27–44%) to 79per cent (74–83%) between 2007 and 2014. Likewise, consistent condom use within days gone by half a year ahead of the study during compensated intimate encounters increased from 35% (30–41%) in 2007 to 61percent (58–64%) in 2014. For non-commercial lovers, russian bride constant condom usage increased from 32per cent (29–36%) in 2007 to 51per cent (49–53%) in 2014. For self-reported experiences of sexually infection that is transmitted, there clearly was a growth from 7% (5–9%) in 2007 to 15percent (13–17%) this year and 19per cent (17–20%) in 2014.