2 New Ebola Vaccines Pass Important Early Test, Researchers Say
Thursday, April 9, 2015
Two new Ebola vaccines have passed an important test, protecting monkeys against the strain of the virus responsible for the current deadly outbreak, researchers reported on Wednesday. Only one dose was needed, and there were no apparent side effects.
The vaccines have not yet been tested in people, but safety trials in healthy volunteers will probably begin early this summer, said Thomas W. Geisbert, an Ebola expert at the University of Texas Medical Branch in Galveston, and the senior author of a report published on Wednesday in the journal Nature.
Tests in nonhuman primates are an important step, because those animals are far more closely related to humans than are other lab animals.
The study of the new vaccines involved 10 macaques. Eight were vaccinated, and two, as controls, were not. The vaccinated animals showed no signs of side effects from the vaccine, Dr. Geisbert said. On the 28th day after the vaccines were given, all the monkeys were injected with Ebola virus from the current outbreak. No vaccinated monkeys became ill, but the unvaccinated ones both died within a week.
The two new vaccines are improved versions of an older one that was licensed to Merckand is now being tested for efficacy in people in Liberia. The older vaccine can cause unpleasant side effects like fever and pain in joints and muscles. (Another vaccine, licensed to GlaxoSmithKline, is also being tested in West Africa, and has not had serious side effects.)
The side effects of the vaccine licensed to Merck were not considered serious enough to block its use. But they could pose problems during an outbreak because they resemble early symptoms of Ebola, so patients with afever soon after vaccination might have to be tested or even quarantined until it was determined whether they were infected or just having a reaction to the shot.