First Human Trial For Malaria Vaccine Takes Place

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Malaria has been one of the most fearsome killing diseases in modern society, where Africa is mostly under attack, due to its climate, sanitary conditions and constant development of malaria vectors – mosquitoes. However, recent scientific news have seen two important and new developments presented in this long-lasting battle against this parasite. 

First one is a vaccine trial in humans, conducted for the first time ever, offering a potential protection against the most present malaria parasite, Plasmodium vivax. The results are so far modest, but promising, as the trial still has to show its efficiency in the time to come. The second important discovery is related to the control methods which are the most effective thus far. The recent evidence has shown that it might be used for much longer, than it was first expected.

The scientific study conducted at the Walter Reed Institute of Research announced that the 30 volunteers had received three trial vaccine doses and were then bitten by the mosquitos which carry P. vivax, 14 days after the received final dose. The results presented in the PLOS Neglected Tropical Diseases journal suggest none of the volunteers suffered serious side effects from the vaccine, although fatigue and headaches were quite common, and all developed a significant immune response.

Unfortunately, the inoculation didn’t prevent the volunteers from catching the malaria, even though the development of the disease was significantly delayed when compared to the six other unvaccinated controls. These results particularly apply to the ten volunteers who were given the highest dosage. P. vivax used for the first human trial is not considered to be the most killing malaria parasite, unlike its relative Plasmodium falciparum, for which the vaccine development is currently more advanced.

However, P. vivax can make the untreated individuals very sick and the symptoms may relapse. The mentioned Plasmodium species were responsible for the loss of more than 400 000 lives in the previous year, where mostly children suffered from this parasite.

Such trial has been a challenge for both volunteers and the researchers. Research team had to arrange the feeding process of mosquitos where their diet would be the blood of the P. vivax infected Thai patient. Unlike P. falciparum, P. vivax cannot be grown in the laboratory conditions but has to be transferred from a diseased patients to mosquitos, and then to the volunteers.

The first author of the study, Lt. Col. Jason stated that the study represented the very first vaccine study which tested the P. vivax vaccine effectiveness in the human candidates, by using the controlled malaria infection. The only drug used for the treatment of P. vivax dormant stages thus far is primaquine, which successfully prevents relapses.

The fear doesn’t only come from the malaria parasites, but also from their vectors, the mosquitos. Mosquitos are known to be one of the fastest resistance-developing creatures, by becoming immune to various insecticides. This additional problems supports the development malaria in Africa, but thanks to the recent human trials, we may develop a new, efficient treatment for this fearsome killing disease.

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