Cawley Caoimhe, Wringe Alison, Slaymaker Emma, Todd Jim, Michael Denna, Kumugola Yusufu, Urassa Mark, Zaba Basia
Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
BMC Infect Dis. 2014 Mar 22;14:159. doi: 10.1186/1471-2334-14-159.
It is widely assumed that voluntary counselling and testing (VCT) services contribute to HIV prevention by motivating clients to reduce sexual risk-taking. However, findings from sub-Saharan Africa have been mixed, particularly among HIV-negative persons. We explored associations between VCT use and changes in sexual risk behaviours and HIV incidence using data from a community HIV cohort study in northwest Tanzania.
Data on VCT use, sexual behaviour and HIV status were available from three HIV serological surveillance rounds undertaken in 2003-4 (Sero4), 2006-7 (Sero5) and 2010 (Sero6). We used multinomial logistic regression to assess changes in sexual risk behaviours between rounds, and Poisson regression to estimate HIV incidence.
The analyses included 3,613 participants attending Sero4 and Sero5 (3,474 HIV-negative and 139 HIV-positive at earlier round) and 2,998 attending Sero5 and Sero6 (2,858 HIV-negative and 140 HIV-positive at earlier round). Among HIV-negative individuals VCT use was associated with reductions in the number of sexual partners in the last year (aRR Seros 4-5: 1.42, 95% CI 1.07-1.88; aRR Seros 5-6: 1.68, 95% CI 1.25-2.26) and in the likelihood of having a non-cohabiting partner in the last year (aRR Seros 4-5: 1.57, 95% CI 1.10-2.25; aRR Seros 5-6: 1.48, 95% CI 1.07-2.04) or a high-risk partner in the last year (aRR Seros 5-6 1.57, 95% CI 1.06-2.31). However, VCT was also associated with stopping using condoms with non-cohabiting partners between Seros 4-5 (aRR 4.88, 95% CI 1.39-17.16). There were no statistically significant associations between VCT use and changes in HIV incidence, nor changes in sexual behaviour among HIV-positive individuals, possibly due to small sample sizes.
We found moderate associations between VCT use and reductions in some sexual risk behaviours among HIV-negative participants, but no impacts among HIV-positive individuals in the context of low overall VCT uptake. Furthermore, there were no significant changes in HIV incidence associated with VCT use, although declining background incidence and small sample sizes may have prevented us from detecting this. The impact of VCT services will ultimately depend upon rates of uptake, with further research required to better understand processes of behaviour change following VCT use.
人们普遍认为，自愿咨询检测（VCT）服务通过促使服务对象减少性行为风险来预防艾滋病病毒（HIV）。然而，撒哈拉以南非洲地区的研究结果并不一致，尤其是在HIV阴性人群中。我们利用坦桑尼亚西北部一项社区HIV队列研究的数据，探讨了VCT使用与性行为风险行为变化及HIV发病率之间的关联。
VCT使用情况、性行为及HIV感染状况的数据来自于2003 - 2004年（血清学检测4轮，Sero4）、2006 - 2007年（血清学检测5轮，Sero5）和2010年（血清学检测6轮，Sero6）进行的三轮HIV血清学监测。我们使用多项逻辑回归评估各轮之间性行为风险行为的变化，并使用泊松回归估计HIV发病率。
分析纳入了参加Sero4和Sero5的3613名参与者（第一轮检测时3474名HIV阴性和139名HIV阳性）以及参加Sero5和Sero6的2998名参与者（第一轮检测时2858名HIV阴性和140名HIV阳性）。在HIV阴性个体中，使用VCT与过去一年性伴侣数量减少相关（Sero4 - Sero5的调整风险比：1.42，95%置信区间1. [07 - 1.88]；Sero5 - Sero6的调整风险比：1.68，95%置信区间1.25 - 2.26），与过去一年有非同居伴侣的可能性降低相关（Sero4 - Sero5的调整风险比：1.57，95%置信区间1.10 - 2.25；Sero5 - Sero6的调整风险比：1.48，95%置信区间1.07 - 2.04），或与过去一年有高危伴侣的可能性降低相关（Sero5 - Sero6的调整风险比1.57，95%置信区间1.06 - 2.31）。然而，VCT使用也与Sero4 - Sero5期间停止与非同居伴侣使用避孕套相关（调整风险比4.88，95%置信区间1.39 - 17.16）。VCT使用与HIV发病率变化之间无统计学显著关联，HIV阳性个体的性行为也无变化，这可能是由于样本量较小。
我们发现VCT使用与HIV阴性参与者某些性行为风险行为的减少之间存在适度关联，但在总体VCT接受率较低的情况下，对HIV阳性个体没有影响。此外，尽管背景发病率下降和样本量较小可能使我们未能检测到，但VCT使用与HIV发病率并无显著变化。VCT服务的影响最终将取决于接受率，并需要进一步研究以更好地理解VCT使用后行为改变的过程。
