Note: Single-source report; awaiting corroboration.
Two clinical trials supported by the National Institutes of Health (NIH) evaluated the experimental PfSPZ malaria vaccine in healthy Malian adults, including women planning to conceive shortly after immunization. All three tested regimens of the vaccine were found to be safe.
One trial enrolled 300 women aged 18 to 38 years, who started with a drug regimen to clear malaria parasites, followed by three vaccine or placebo injections over a month. Both vaccine dosages provided significant protection against parasitemia and clinical malaria, sustained over two years without the need for a booster—the first time for any malaria vaccine.
Among 55 women who became pregnant within 24 weeks after the third vaccine dose during the first trial year, vaccine efficacy against parasitemia was 65% for the lower dose group and 86% for the higher dose. Across both years, among 155 women who conceived, efficacy was 57% for the lower dose and 49% for the higher dose groups.
The protective effect in pregnant women suggests a promising strategy for malaria prevention in pregnancy—a condition responsible for up to 50,000 maternal deaths and 200,000 stillbirths annually in Africa. The investigational vaccine uses radiation-attenuated Plasmodium falciparum sporozoites and has previously demonstrated safety in malaria-endemic regions, including prior trials in Burkina Faso with up to 46% efficacy lasting 18 months.
The studies were co-led by NIH's National Institute of Allergy and Infectious Diseases and the University of Sciences, Techniques and Technologies in Bamako, Mali, with the vaccine manufactured by Sanaria Inc., Rockville, Maryland.