Sustained clinical benefit of malaria chemoprevention with sulfadoxinepyrimethamine (SP) in pregnant women in a region with high SP resistance markers

Objective: The effectiveness of intermittent preventive treatment of malaria in pregnancy with sulfadoxinepyrimethamine (IPTp-SP) is threatened by increasing SP -resistance in Africa. We assessed the level of SPresistance markers, and the clinical and parasitological effectiveness of IPTp-SP in southern Mozambique. Methods: P. falciparum infection, antimalarial antibodies and dhfr/dhps SP -resistance mutants were detected by quantitative polymerase chain reaction (qPCR), suspension array technology and targeted deep sequencing, respectively, among 4016 HIV -negative women in Maputo province (2016-2019). Univariate and multivariate regression models were used to assess the association between taking the recommended three or more IPTp-SP doses (IPTp3+) and parasitological and clinical outcomes. Results: 84.3% (3385/4016) women received three or more IPTp-SP doses. The prevalence of quintuple mutants at first antenatal care (ANC) visit was 94.2%. IPTp3+ was associated with a higher clearance rate of qPCR-detected infections from first ANC visit to delivery (adjusted odds ratio [aOR]=5.9, 95% CI: 1.5-33.3; p = 0.012), lower seroprevalence at delivery of antibodies against the pregnancy -specific antigen VAR2CSADBL34 (aOR=0.72, 95% CI: 0.54-0.95; p = 0.022), and lower prevalence of low birth weight deliveries (aOR: 0.61, 95% CI: 0.41-0.90; p = 0.013). Conclusion: A sustained parasitological effect of IPTp-SP contributes to the clinical effectiveness of IPTp3+ in areas with high prevalence of SP -resistance markers. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of The British Infection Association. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).