Malaria vaccine candidate effective 1 year after vaccination
An investigational malaria vaccine protected a small number of healthy participants in the United States more than 1 year after vaccination, according to data from a phase 1 trial.
The PfSPZ Vaccine (Sanaria) is a live-attenuated vaccine containing the early developmental form of Plasmodium falciparum, according to an NIH press release. Previous studies evaluating the efficacy of PfSPZ showed the vaccine was protective 3 weeks after vaccination. For the current trial, Andrew S. Ishizuka, MD, PhD, of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases, and colleagues assessed whether the vaccine’s efficacy persisted between 5 months and 1 year.
Anthony S. Fauci
“Malaria remains one of the most devastating diseases in the world, especially among young children in Africa,” Anthony S. Fauci, MD, NIAID director, said in the release. “A malaria vaccine that provides long-term protection is urgently needed to reduce mortality and eliminate transmission. This study is an encouraging step forward in our goal to control and ultimately eradicate malaria.”
The researchers assigned four IV doses of the vaccine to 11 healthy adult participants and exposed them to mosquitoes infected with P. falciparum 21 weeks after immunization. Among them, six participants had no detectable parasites in their blood. Four of these participants and an additional participant who also received four IV doses were exposed to the mosquitoes again 59 weeks after their final vaccination. None of the participants developed infection.
In addition to long-term efficacy, the vaccine was well-tolerated with no adverse events reported during the trial, according to the release.
“It is now clear that administering the PfSPZ Vaccine intravenously confers long-term, sterile protection in a small number of participants, which has not been achieved with other current vaccine approaches,” Robert A. Seder, MD, chief of the Cellular Immunology Section of NIAID’s Vaccine Research Center, said in the release. “Based on the favorable safety profile, we’re testing higher doses in larger trials to see if even greater protection can be achieved long-term against other P. falciparum strains different than the vaccine strain.”
Disclosure: Ishizuka reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.