Early promise for malaria vaccine that mimics bites
By Kerry Sheridan ,AFPWASHINGTON -- A new kind of malaria vaccine that mimics the effect of mosquito bites has shown early promise by offering 100 percent protection to a dozen human volunteers, researchers said Thursday.
August 10, 2013, 12:08 am TWN
The experimental vaccine, called PfSPZ and produced by the Maryland-based company Sanaria, contains live malaria parasites collected through a painstaking process of dissecting the salivary glands of mosquitoes.
These immature parasites, known as sporozoites, are then weakened so they cannot cause illness and incorporated into a vaccine, which must be injected into a person's veins several times, with each shot about a month apart.
“When we started doing this, everybody knew that sporozoites were the gold standard but everyone thought it was impossible to make a vaccine out of sporozoites and we were crazy. And we have proven them wrong,” Sanaria chief scientific officer Stephen Hoffman told AFP.
A test two years ago that administered the same vaccine into the skin of patients, the way most vaccines are given, protected only two of 44 volunteers.
But the latest trial showed that injecting the vaccine into the bloodstream protected against malaria in all six volunteers who received a five-shot regimen at the highest dosage, according to the results published in the U.S. journal Science.
Six of nine volunteers in a separate group that received four shots of the highest dose — 135,000 sporozoites per injection — were also fully protected against malaria, it said.
The phase I study included 57 people — including 40 who received the vaccine in varying doses and 17 controls.
The study was co-authored by Hoffman and Robert Seder of the National Institute of Allergy and Infectious Diseases (NIAID).
“The good news is that the proof of concept is quite impressive,” said Anthony Fauci, director of NIAID.