Mda Pamela, Mngadi Kathryn, Zhang Bo, Burnham Randy, Juraska Michal, Hyrien Ollivier, Garrett Nigel, Dubula Thozama, Toni Sinalo, Joseph Sibi, Kotze Phillip, Buchbinder Susan, Takalani Azwidihwi, Tomaka Frank, Luedtke Alexander, Willems Wouter, Swann Edith, Hutter Julia, Gelderblom Huub, McElrath M Juliana, Lavreys Ludo, Stranix-Chibanda Lynda, Roxby Alison C, Bekker Linda-Gail, Gray Glenda E
Nelson Mandela Academic Clinical Research Unit, Walter Sisulu University, Mthatha, South Africa.
The Aurum Institute, Johannesburg, South Africa.
Front Reprod Health. 2025 Jun 10;7:1565933. doi: 10.3389/frph.2025.1565933. eCollection 2025.
HIV vaccine trial participants include sexually active cisgender females who agree to avoid pregnancy during the active vaccination period. Nevertheless, some pregnancies occur in almost all studies. We examined contraceptive use, pregnancy incidence, and the relationship between pregnancy and HIV seroconversion in one HIV vaccine trial.
We performed an exploratory analysis of data collected for HVTN 705/HPX2008, a phase IIb HIV vaccine trial enrolling cisgender women across 23 sites in five southern African countries. Baseline characteristics and contraceptive use were assessed among participants who became pregnant and those who did not during the active vaccination phase (months 0-15). Pregnancy incidence rates were calculated for this phase and the duration of follow up (36 months). Cox regression analysis was used to assess factors associated with incident pregnancy.
There were 2,636 participants who received at least one vaccine or placebo dose (mean age: 23 years, standard deviation: 3 years). At enrolment, when contraception was required, 62.9% reported using injectable contraceptives. Overall pregnancy rate was 2.95 per 100 person-years (95% CI: 2.40, 3.58), with 101 pregnancies reported by month 15. Cumulative incidence of pregnancy at month 15 was similar between trial arms (log-rank = 0.688). Each additional year of age was associated with an 8% decrease in pregnancy incidence ( = 0.014). Women aged 31-35 years had the lowest pregnancy incidence [1.75 (0.48, 4.48) per 100 person-years]. In a Cox regression analysis covering months 0-15, all contraceptive methods significantly reduced the incidence of pregnancy compared to no contraceptive use. Oral contraception was associated with the least reduction in pregnancy risk; implants were associated with the most reduction in pregnancy risk ( < 0.001).
In HVTN 705/HPX2008, higher incidence of pregnancy was associated with younger age and oral contraception (compared to other methods). These data may inform future designs of HIV prevention or vaccine trials.
HIV疫苗试验参与者包括性活跃的顺性别女性，她们同意在疫苗接种期内避免怀孕。然而，几乎所有研究中都会出现一些怀孕情况。我们在一项HIV疫苗试验中研究了避孕措施的使用、怀孕发生率以及怀孕与HIV血清转化之间的关系。
我们对为HVTN 705/HPX2008收集的数据进行了探索性分析，这是一项IIb期HIV疫苗试验，在五个南部非洲国家的23个地点招募顺性别女性。在疫苗接种活跃期（第0至15个月）期间怀孕和未怀孕的参与者中评估基线特征和避孕措施的使用情况。计算该阶段及随访期（36个月）的怀孕发生率。使用Cox回归分析评估与怀孕事件相关的因素。
有2636名参与者接受了至少一剂疫苗或安慰剂（平均年龄：23岁，标准差：3岁）。在入组时，当需要采取避孕措施时，62.9%的人报告使用注射用避孕药。总体怀孕率为每100人年2.95例（95%置信区间：2.40，3.58），到第15个月时报告了101例怀孕。各试验组在第15个月时的怀孕累积发生率相似（对数秩检验=0.688）。年龄每增加一岁，怀孕发生率降低8%（P=0.014）。31至35岁的女性怀孕发生率最低[每100人年1.75例（0.48，4.48）]。在涵盖第0至15个月的Cox回归分析中，与未采取避孕措施相比，所有避孕方法均显著降低了怀孕发生率。口服避孕药与怀孕风险降低幅度最小相关；植入物与怀孕风险降低幅度最大相关（P<0.001）。
在HVTN 705/HPX2008中，较高的怀孕发生率与年轻年龄和口服避孕药（与其他方法相比）相关。这些数据可为未来HIV预防或疫苗试验的设计提供参考。
