By IDSE News Staff
National Institutes of Health–sponsored research in Malian adults found that all tested regimens of an experimental malaria vaccine provided durable protection from the malaria parasite (Lancet Infect Dis 2024 Aug 14. doi:10.1016/S1473-3099[24]00360-8).
The research was co-led by investigators from the NIH’s National Institute of Allergy and Infectious Diseases and the University of Sciences, Techniques and Technologies, in Bamako, Mali. The investigational vaccine was Sanaria’s PfSPZ Vaccine, a radiation-attenuated vaccine based on Plasmodium falciparum sporozoites (a stage of the malaria parasite’s life cycle). Previous studies have suggested that the vaccine is safe and demonstrated up to 46% efficacy at 18 months follow-up.
The phase 2 MLSPZV4 trial enrolled 300 healthy women between the ages of 18 and 38 years who anticipated becoming pregnant soon after immunization. The participants were treated to remove malaria parasites and given three injections spaced over a month of placebo or the investigational vaccine at one of two dosages. Both dosages conferred significant protection from infection (including among pregnant participants) and clinical malaria over two years without a booster dose.
Pregnant people, young children and infants are particularly vulnerable to life-threatening disease caused by the malaria parasite. The NIH noted that malarial parasitemia in pregnancy is estimated to cause up to 50,000 maternal deaths and 200,000 stillbirths in Africa each year.
In the first year of the trial, 55 women began pregnancy within 24 weeks of the third vaccine dose. In this group, vaccine efficacy against parasitemia before or during pregnancy was, respectively, 65% and 86% in those who received the lower and higher doses of the vaccine. Among 155 women who conceived across both study years, vaccine efficacy was, respectively, 57% and 49% for those who received the lower and higher doses of the vaccine.
“Preconception immunization is a new strategy to reduce mortality for women with malaria in pregnancy,” wrote the researchers, who plan to investigate the safety of the vaccine administered before and during pregnancy in larger trials. “Existing measures are not protecting women from malaria in pregnancy. … A safe and effective vaccine is urgently needed, and our results indicate PfSPZ Vaccine might be a suitable candidate.”
Based on NIH press materials.
