January 17th, 2017

Eilat / Chikungunya Vaccine Candidate Ready for Human Trials

Chikungunya is a viral disease transmitted to humans by infected mosquitoes

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Researchers from The University of Texas Medical Branch (UTMB) at Galveston have developed the first vaccine for chikungunya fever made from an insect-specific virus that doesn’t have any side effects on people.

This potentially makes the vaccine safe and effective.

The newly developed vaccine quickly produces a strong immune defense and completely protects mice and nonhuman primates from disease when exposed to the chikungunya virus.

“This vaccine offers efficient, safe and affordable protection against chikungunya and builds the foundation for using viruses that only infect insects to develop vaccines against other insect-borne diseases,” said UTMB professor Scott Weaver, senior author of this paper.

Chikungunya is a viral disease transmitted to humans by infected mosquitoes. It causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash.

Some patients will feel better within a week but many develop longer-term joint pain that can last up to years. There is no cure for the disease.

Death is rare but can occur.

These researchers used the Eilat virus as a vaccine platform since it only infects insects and has no impact on people. The UTMB researchers used an Eilat virus clone to design a hybrid virus-based vaccine containing chikungunya structural proteins.

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The Eilat/Chikungunya vaccine was found to be structurally identical to natural chikungunya virus.

The difference is that although the hybrid virus replicates very well in mosquito cells, it cannot replicate in mammals.

Within four days of a single dose, the Eilat/Chikungunya candidate vaccine induced neutralizing antibodies that lasted for more than 290 days.

These antibodies provided complete protection against chikungunya in two different mouse models. In nonhuman primates, Eilat/Chikungunya elicited rapid and robust immunity – there was neither evidence of the virus in the blood nor signs of illness such as fever after chikungunya virus infection.

The chikungunya disease occurs in Africa, Asia and the Indian subcontinent. In recent decades mosquito vectors of chikungunya have spread to Europe and the Americas. In 2007, disease transmission was reported for the first time in a localized outbreak in north-eastern Italy. Outbreaks have since been recorded in France and Croatia.

The disease shares some clinical signs with dengue, and can be misdiagnosed in areas where dengue is common.

Other authors include UTMB’s Jesse Erasmus, Albert Auguste, Huanle Luo, Shannan Rossi, Karla Fenton, Grace Leal and Tian Wang; Jason Kaelber and Wah Chiu from Baylor College of Medicine; Dal Kim and Ilya Frolov from the University of Alabama at Birmingham and Farooq Nasar from the United States Army Medical Research Institute of Infectious Diseases.

The findings are detailed in Nature Medicine. No conflicts of interest were disclosed. No cost for this vaccine were published.