Following a promising trial of an experimental vaccine to protect against the mosquito-borne illness chikungunya, the National Institutes of Health is starting a second phase.
The new trial will enroll 400 healthy volunteer adults, ages 18 to 60, at six sites in the Caribbean to gather data on the vaccine’s safety and ability to elicit immune responses, including antibodies, according to a new release. Eligible volunteers will be randomly assigned to enroll into one of two groups of 200 people each. Study participants will receive either two doses of the candidate vaccine spaced 28 days apart or two doses of an inactive placebo. Blood samples will be drawn at multiple time points following the injections to assess whether the candidate vaccine prompted the production of antibodies to chikungunya virus, according to the release.
An initial trial of the vaccine was developed by NIH’s National Institute of Allergy and Infectious Diseases scientists who reported in 2014 that all 25 recipients in a study of the experimental vaccine developed robust immune responses with no safety issues, according to the release.
Chikungunya virus is transmitted to people via mosquitoes. The most common symptoms of chikungunya virus infection are fever and joint pain, and sometimes headache, muscle pain, joint swelling and rash, according to the CDC. Outbreaks have occurred in Africa, Asia, Europe and the Indian and Pacific Oceans. In late 2013, the chikungunya virus was found for the first time in the Americas on islands in the Caribbean. Since then, numbers of cases have increased, and in 2015, more than 621,000 suspected and confirmed cases have been reported throughout the Americas, according to the CDC.
“The recent re-emergence of chikungunya virus in this hemisphere has rapidly become a significant health burden,” NIAID Director Anthony S. Fauci, MD, said in the release. “Our chikungunya vaccine development efforts are part of a broader research effort to prevent, diagnose, treat and ultimately control this painful illness, which can strike anyone unlucky enough to be bitten by an infected mosquito.”
The experimental vaccine, developed by investigators at NIAID’s Vaccine Research Center, uses virus-like particles instead of either inactivated or weakened whole virus, according to the release. VLP vaccines can stimulate immune responses comparable to those resulting from naturally acquired immunity following infection.
For more information, visit Clinicaltrials.gov and search for NCT02562482.
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