World’s First Chikungunya Vaccine Developed From Insect-Specific Virus

Highlights:

• The first vaccine for Chikungunya has been developed from an insect-specific virus.
• The vaccine was found to be safe and effective to produce a strong immune defense against the virus.
• A single shot of vaccine produced antibodies that lasted for 290 days.

A safe and effective vaccine for Chikungunya fever made from an insect-specific virus has been developed by a team of researchers from The University of Texas Medical Branch at Galveston. The researchers found that the vaccine strengthened the immune system and protected mice and non-human primates from disease when exposed to the Chikungunya virus.

Eilat Virus as a Vaccine for Chikungunya

Vaccine development is based on two factors- the first is safety, and the other is how quickly the vaccine works. Traditionally, live-attenuated vaccines were developed from weakened live pathogens. Those vaccines offered rapid and durable immunity but reduced safety.

Inactivated vaccines were also developed to offer protection, but it often required multiple doses and boosters to work efficiently. Both the live-attenuated and inactive form of vaccines increased the risk, either from incomplete inactivation of the pathogen or unstable weakening of the live virus.

The research team at The University of Texas Medical Branch used the Eilat virus as a vaccine platform to overcome the trade-offs that were seen while using live-attenuated or inactivated vaccines. The Eilat virus only infects insects and has no effect on people.

An Eilat virus clone was used to design a hybrid virus-based vaccine containing Chikungunya structural proteins.

The newly developed Chikungunya vaccine was structurally identical to natural Chikungunya virus. However, the difference is that the hybrid virus replicates in mosquito cells, but, it cannot replicate in mammals.

Efficacy of the Newly Developed Chikungunya Vaccine

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The researchers tested the safety and efficacy of the newly developed Chikungunya virus in mice and non-human primates. The tests showed that a single dose of Chikungunya vaccine induced neutralizing antibodies within four days. The efficacy of the vaccine lasted for more than 290 days.

The vaccine was found to provide complete protection against the Chikungunya virus in two different mouse models. However, in the non-human primates, there was neither evidence of the virus in the blood nor symptoms of Chikungunya.

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"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 the lead author of the study, Scott Weaver, a professor at UTMB.

The findings of the study are detailed in Nature Medicine.

Chikungunya

Chikungunya is a mosquito-borne disease that causes fever and joint pain. Some of the other symptoms of Chikungunya include fatigue, muscle pain, headache, and rash. Some individuals may recover within a week, but many develop long-term joint pain.

Facts

• Chikungunya-causing mosquitoes are Aedes aegypti and Aedes albopictus.
• The onset of illness after the bite of an infected mosquito is between 4 and eight days, but can also range from 2 to 12 days.
• Chikungunya cases have been reported in over 60 countries in Asia, Africa, Europe and the Americas.
• There is no commercial vaccine or anti-viral treatment for chikungunya.
• In 2015, more than 1.4 million chikungunya cases were reported in the Caribbean Islands, in Latin American countries, and in the United States.
• A total of 12,255 Chikungunya cases were reported in India in 2016.

Tips to Prevent Chikungunya

• Wear long sleeved shirts to prevent mosquito bite
• Use repellent sprays and creams
• Use mosquito nets
• Keep the surroundings clean to prevent breeding of mosquitoes.

References:

1. Chikungunya Virus - (http://www.mayoclinic.org/diseases-conditions/infectious-diseases/expert-answers/what-is-chikungunya-fever/faq-20109686)
2. What is chikungunya fever, and should I be worried? - (https://www.cdc.gov/chikungunya/symptoms/)

Source-Medindia