Randomized controlled safety and efficacy trial of 2 vitamin A supplementation schedules in Tanzanian infants.

Randomized controlled trial in newborn infants and their mothers in Ifakara, southern Tanzania, with vitamin A deficiency concerns. The high-dose group had 390 participants randomized and the low-dose group had 390 participants randomized; infants were enrolled at about 1 month of age and followed through 9 months alongside routine immunizations.

The high-dose regimen used oral vitamin A palmitate capsules for mothers and infants at routine vaccination visits: mothers received 200,000 IU at the infant's BCG visit and again at the first DPT/OPV visit, and infants received 50,000 IU at each of the 3 DPT/OPV visits. The low-dose regimen gave mothers 200,000 IU at the BCG visit and infants 25,000 IU at the 3 DPT/OPV visits; all infants also received 100,000 IU at measles vaccination.

The higher-dose vitamin A regimen was safe but did not meaningfully improve vitamin A status or reduce morbidity compared with the lower-dose regimen. At 6 months, there were no significant differences in MRDR deficiency, serum retinol, or breast milk retinol; for example, MRDR 0.06 was 43% versus 47% (RR 0.91, 95% CI 0.76 to 1.09; P = 0.32) and serum retinol 0.70 μmol/L was 36% versus 41% (RR 0.89, 95% CI 0.73 to 1.09; P = 0.25). At 9 months, results remained null, including MRDR 0.06 at 41% versus 40% (RR 1.01, 95% CI 0.83 to 1.24; P = 0.91) and serum retinol 0.70 μmol/L at 29% versus 32% (RR 0.93, 95% CI 0.72 to 1.18; P = 0.54). Reported illness signs and symptoms after supplementation were also similar between groups, and some vitamin A capsules degraded, raising implementation quality-control concerns.

The trial found no clear efficacy advantage despite a biologically plausible higher-dose strategy, and the source notes that some vitamin A capsules degraded, which could have affected delivered dose and implementation. The available summary also suggests limited separation between groups on key biomarkers, making the intervention effect difficult to detect under field conditions.