Experimental Malaria Vaccine Shows Positive Results In Early Clinical Trial In Humans, Researchers Report

“An experimental malaria vaccine proved highly effective in a small, early-stage clinical trial in people, raising hope in the global effort to combat the deadly disease, U.S. researchers reported on Thursday in the journal Science,” Reuters reports (Stewart, 8/8). “Researchers found the vaccine, which is being developed in the U.S., protected 12 out of 15 patients from the disease, when given in high doses” intravenously, BBC News writes (Morelle, 8/8). “The vaccine — called PfSPZ because it is made from sporozoites (SPZ), a stage in the life cycle of the malarial parasite Plasmodium falciparum (Pf) — uses a weakened form of the whole parasite to invoke an immune response,” Nature notes (Butler, 8/8). Of 57 healthy adult participants, “40 participants received the vaccine and 17 did not,” an NIH press release states, noting, “To evaluate the vaccine’s safety, vaccinees were split into groups receiving two to six intravenous doses of PfSPZ vaccine at increasing dosages” (8/8). “Of the 15 participants who received higher dosages of the vaccine, only three became infected, compared to 16 of 17 participants in the lower dosage group who became infected,” Xinhua writes, noting 11 of the 12 participants who received no vaccine became infected (8/9).

“‘With this intravenous vaccine, we are striving to reach the [WHO] goal of a [malaria] vaccine with 80 percent efficacy by 2025,’  Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID), told Nature Medicine,” a post in the magazine’s blog states. “The clinical study was led by Robert Seder, an immunologist at the NIAID Vaccine Research Center, and involved a vaccine developed by Stephen Hoffman and his colleagues at Sanaria, a biotechnology company based in Rockville, Maryland,” the blog notes (Devitt, 8/8). “Though the results were promising, more extensive field testing will be required, the researchers wrote,” CNN reports (Smith/Hudson, 8/9). “The study was extremely small and short-term. And the candidate vaccine still has a long way to go before it could be used in the developing world,” according to NPR’s “Shots” blog (Beaubien, 8/8). “To date, only one experimental vaccine, called RTS,S or Mosquirix, developed by GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative, with funding from the Bill & Melinda Gates Foundation, has demonstrated a consistent protective effect,” the Nature Medicine blog adds, noting “last year the results of a phase III clinical trial indicated that it offered only about 30-35 percent protection when given to infants between six weeks and 12 weeks of age” (8/8).

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