Malaria is caused by a protozoan parasite called Plasmodium. It affects around 250 million people worldwide every year. Scientists have developed vaccines against malaria before; however, they are only effective in 75% of individuals and require booster doses. Thus, the search for better vaccines is still on the go, with this new one paving a new and unique way of immunizing people against malaria.
This new vaccine, delivered through mosquito bites, consists of genetically modified malaria parasites that do not cause malaria but can help the body become acquainted with it. In a trial, this reduced the susceptibility to malaria in participants.
What does the vaccine contain
In humans, the malarial parasite Plasmodium reaches the liver, where they reproduce asexually before attacking red blood cells, where they reproduce in both asexual and in a later sexual phase. The scientists have used modified Plasmodium falciparum parasites, which cause malaria in its wild form. In one instance, scientists have genetically modified the organism to stop developing after 24 hours of infection, called GA1. In the other case, the team has developed a variant that stops developing after six days post-infection, called GA2. The participants were exposed to mosquitos that carried either GA1 or GA2. Once bitten, the modified parasite entered the participants’ body and provided immunity against malaria. How well did the two variants fare? We will see that in the next segment.
GA1 vs GA2: Which worked best
In the trial, participants received 50 mosquito bites; 10 received bites from GA1-carrying mosquitos and another 10 from GA2-carrying mosquitos. Three weeks later, they were exposed to bites from mosquitos that carried malaria. Both groups had higher levels of antibodies than before, and one of eight (13%) GA1 recipients didn’t contract malaria, compared to an 89% success rate in the case of GA2 recipients. GA1 protected fewer participants compared to GA2. The researchers are now eager to replicate the results in a larger trial.
According to immunologist Julius Hafalla, the vaccine GA2 must be followed up with extensive studies before being marked as a candidate in global malaria control.
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