This Week in Infectious Disease: HIV Prevention and H. pylori Eradication

From the New England Journal of Medicine, a trial involving 9,289 critically ill patients across 26 ICUs in Australia and Canada evaluated Selective Decontamination of the Digestive Tract ^[4].

At 90 days, SDD did not reduce in-hospital death from any cause compared with standard care, though it reduced new bloodstream infections and cultured antibiotic-resistant organisms. The findings suggest that while SDD alters microbiome dynamics, its impact on hard clinical endpoints like mortality remains uncertain in this setting. Meanwhile, attention turned to HIV prevention strategies, where a Cochrane systematic review and meta-analysis of two randomised controlled trials ^[1] compared six-monthly subcutaneous lenacapavir with daily oral F/TDF or F/TAF PrEP in HIV-negative people at sexual risk. Lenacapavir produced a large reduction in new HIV infections at 52 weeks, with high-certainty evidence, alongside more injection site reactions. These results support considering injectable lenacapavir as a highly effective PrEP alternative to oral regimens, accepting the trade-off of more injection site reactions.

Elsewhere this week, researchers in Human vaccines & immunotherapeutics reported on a Phase 3 randomized controlled trial ^[5] that evaluated the association between the Ad5-nCoV vaccine and HIV infection risk in 44,247 HIV-negative participants across five countries. Over a six-month follow-up period, HIV incidence rates were similar between the vaccine and placebo groups, with no discernible difference in baseline prevalence. These results suggest that pre-existing adenovirus type 5 neutralizing antibodies do not confer an increased risk of HIV infection following vaccination, though the assessment is limited to short-term outcomes. We also saw research in PloS one, which presented a systematic review and meta-analysis evaluating virologic suppression among 304,883 HIV-positive pregnant and lactating women in Africa ^[2].

The pooled estimate for achieving an undetectable viral load was 60.92%, while overall virologic suppression was 80.86%. These findings highlight the necessity of targeted strategies for younger women, partner disclosure, first-line regimens, and adherence, though observational data precludes causal inference.

Finally, in the realm of gastrointestinal infections, a systematic review and meta-analysis published in Journal of gastrointestinal and liver diseases : JGLD examined 7,498 Asian patients with Helicobacter pylori infection ^[3].

Vonoprazan-based therapies showed an overall eradication rate of 94% (95%CI: 0.91-0.96) with a 6% absolute risk difference favoring vonoprazan when compared to proton pump inhibitor-based therapies. These findings suggest vonoprazan may offer modest advantages over PPIs, though safety data and generalizability require consideration. Collectively, this week's research offers nuanced insights into prevention, treatment efficacy, and safety profiles across diverse infectious disease contexts.