Impact of intermittent preventive treatment of malaria in pregnancy with dihydroartemisinin-piperaquine versus sulfadoxine-pyrimethamine on the incidence of malaria in infancy: a randomized controlled trial

Background: Intermittent preventive treatment of malaria during pregnancy (IPTp) with dihydroartemisinin-piperaquine (DP) significantly reduces the burden of malaria during pregnancy compared to sulfadoxine-pyrimethamine (SP), the current standard of care, but its impact on the incidence of malaria during infancy is unknown. Methods: We conducted a double-blind randomized trial to compare the incidence of malaria during infancy among infants born to HIV-uninfected pregnant women who were randomized to monthly IPTp with either DP or SP. Infants were followed for all their medical care in a dedicated study clinic, and routine assessments were conducted every 4 weeks. At all visits, infants with fever and a positive thick blood smear were diagnosed and treated for malaria. The primary outcome was malaria incidence during the first 12 months of life. All analyses were done by modified intention to treat. Results: Of the 782 women enrolled, 687 were followed through delivery from December 9, 2016, to December 5, 2017, resulting in 678 live births: 339 born to mothers randomized to SP and 339 born to those randomized to DP. Of these, 581 infants (85.7%) were followed up to 12 months of age. Overall, the incidence of malaria was lower among infants born to mothers randomized to DP compared to SP, but the difference was not statistically significant (1.71 vs 1.98 episodes per person-year, incidence rate ratio (IRR) 0.87, 95% confidence interval (CI) 0.73-1.03, p = 0.11). Stratifying by infant sex, IPTp with DP was associated with a lower incidence of malaria among male infants (IRR 0.75, 95% CI 0.58-0.98, p = 0.03) but not female infants (IRR 0.99, 95% CI 0.79-1.24, p = 0.93). Conclusion: Despite the superiority of DP for IPTp, there was no evidence of a difference in malaria incidence during infancy in infants born to mothers who received DP compared to those born to mothers who received SP. Only male infants appeared to benefit from IPTp-DP suggesting that IPTp-DP may provide additional benefits beyond birth. Further research is needed to further explore the benefits of DP versus SP for IPTp on the health outcomes of infants.