Can Daily Zinc Supplements Lower Infection Rates in Children With Sickle Cell Anemia?

According to Medical Dialogues' coverage of the ZIPS-2 randomized clinical trial published in JAMA, daily 20-mg oral zinc sulfate cut all-cause infections by 38% over six months in 100 Ugandan children under five with sickle cell anemia, with no adverse events requiring treatment discontinuation. If the signal holds in a larger cohort, it shifts the prophylaxis conversation for one of pediatric hematology's most infection-vulnerable populations. Before anyone reorders clinical workflow, though, the trial design deserves a hard look.

Reading the endpoints

The investigators randomized 100 children aged 1.00 to 4.99 years at Jinja Regional Referral Hospital in Uganda — 50 to zinc, 50 to placebo — between February and April 2025, with follow-up running through November 2025. The primary efficacy endpoint was all-cause infectious events per 100 person-years, judged by strict clinical diagnostic criteria rather than parent-reported symptoms. Retention hit 100%, which is uncommon in pediatric trials and worth noting on its own.

The 45% of participants already on disease-modifying hydroxyurea continued their regimen throughout, so the zinc effect is layered on top of standard therapy, not tested against it. That distinction matters: the 38% relative reduction is real within this cohort, but isolating zinc's contribution from hydroxyurea's immunomodulatory role will require a factorial design in future work.

Safety profile and the limits of n=100

The zero adverse-event-discontinuation rate is encouraging. In my experience running these cohorts, though, a six-month window with 100 participants is too short and too small to catch rare events — particularly in a population with sickle cell anemia, where organ-specific toxicities can take longer to surface. The trial's own authors, per the Medical Dialogues report, recommend larger multisite trials and extension to older pediatric patients before clinical adoption at scale.

Geographic specificity is another caveat I would flag: 100 Ugandan children reflect a particular nutritional baseline, pathogen exposure profile, and genetic context. If baseline zinc status was marginal in this cohort, the effect size may not generalize to well-nourished sickle cell populations in higher-income settings.

What to watch next

Two things on my monitoring list: the multisite trial the authors explicitly call for, and any pharmacokinetic data on zinc–hydroxyurea interaction, since nearly half the cohort was on both. Until then, I am comfortable flagging zinc as a low-cost adjunct worth discussing with families whose children have sickle cell anemia and recurrent infections — but I would not frame it as a substitute for hydroxyurea, standard vaccination, or indicated prophylactic antibiotics.