Experimental vaccine shows promise of protection against malaria for over a year

A new experimental vaccine has shown promising results in tests when given in varying doses to human subjects in a study, PTI reported.

The new study showed that the new vaccine, known as the PfSPZ Vaccine, gave 55 per cent protection for more than one year to a few healthy adults.

The US-based pharmaceutical company Sanaria, which developed and produced the vaccine used thousands of thousands of live, but weakened P falciparum sporozoites - the early developmental form of the parasite.

For the phase one clinical trial, NIAID researchers and collaborators at the University of Maryland School of Medicine in Baltimore who conducted the clinical evaluation of the vaccine, enrolled 101 healthy adults aged 18 to 45 years who had never had malaria.

The vaccine was administered to 59 per cent of the volunteers while 32 participants served as controls and were not vaccinated.

In order to assess the roles of the route of administration, dose and number of immunisations in conferring short- and long-term protection against malaria, vaccine recipients were divided into several groups.

To assess the efficacy of the vaccine in preventing malaria infection, all participants - including the control participants who were not vaccinated - were  subject to the bites of mosquitoes carrying the same P falciparum strain from which the vaccine was derived.

The vaccine was found to provide protection against malaria for more than one year in 55 per cent of people who had had no malaria infection earlier.

"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," said principal investigator of the trial Robert Seder from National Institute of Allergy and Infectious Diseases (NIAID).

Previous tests had shown that the PfSPZ vaccine was highly protective three weeks after immunisation. In this trial, researchers assessed if protection could extend to a year.

For the phase one clinical trial, the researchers enrolled 101 healthy adults aged 18 to 45 years who had never had malaria.

Of these volunteers, 59 received the vaccine and 32 participants served as controls and were not vaccinated.

Vaccine recipients were divided into several groups to assess the roles of the route of administration, dose, and number of immunisations in conferring short- and long-term protection against malaria.