Daily zinc was linked to fewer infections in young children with sickle cell anaemia

Design

Randomised, double-blind, placebo-controlled trial (ZIPS-2), single site, Uganda

Population

100 children aged 1 to 4.99 years with sickle cell anaemia, all on hydroxyurea

Primary outcome

All-cause infections per 100 person-years over 6 months

Effect

305.7 vs 480.7 per 100 person-years; adjusted IRR 0.62 (95% CI 0.45 to 0.86)

ZIPS-2 was a randomised, double-blind, placebo-controlled trial at one referral hospital in Jinja, Uganda. It enrolled 100 children aged 1 to under 5 years with sickle cell anaemia, who all started or continued hydroxyurea. They received zinc sulfate 20 mg daily or placebo for six months. No child was lost to follow-up.

There were 80 all-cause infections in the zinc group and 124 with placebo: 305.7 vs 480.7 per 100 person-years (rate difference -176.0, 95% CI -300.8 to -51.3). The adjusted incidence rate ratio was 0.62 (95% CI 0.45 to 0.86). No adverse event led to stopping the intervention in either group.

The design is small and single-site, and the authors call for multisite trials and for testing in older children. It is encouraging for settings with a high sickle cell burden and limited access to other infection prevention, but it does not replace penicillin prophylaxis, vaccination or malaria chemoprevention.

• Zinc 20 mg daily lowered all-cause infections to 305.7 from 480.7 per 100 person-years (adjusted IRR 0.62).
• The trial was in 100 children aged 1 to 5, all on hydroxyurea, at one Ugandan hospital.
• No adverse event led to stopping zinc in either group.
• Do not use it in place of penicillin prophylaxis, vaccines or malaria prevention.
• Discuss zinc as an add-on only where there is a local programme, and wait for multisite confirmation.

Why it matters

Infection remains a leading cause of death in sickle cell anaemia in sub-Saharan Africa, and zinc is cheap, which makes it worth testing properly.

Don't overread it

A single-site trial of 100 children with an all-cause infection endpoint cannot show reduced hospitalisation or death.

The statistics, in plain English

An incidence rate ratio of 0.62 means infections occurred at about 62% of the placebo rate. The confidence interval (0.45 to 0.86) excludes 1.0, but with only 204 infections in 100 children, the true size of the effect could be well off the point estimate. Counting all infections together lumps trivial and serious episodes.

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