World’s First Safe Chikungunya Vaccine Developed

Currently, there is no commercial Chikungunya vaccine. This discovery may change that.

The new vaccine protects mice and non-human primates from disease when exposed to the virus. (Photo: AP)

The Chikungunya virus returns to plague India every year. In the past year, the Capital’s AIIMS alone tested around 900 samples of Chikungunya in the months of July and August.

While there is no commercial vaccine as of right now, researchers have developed the first vaccine of its kind for Chikungunya fever, made from an insect-specific virus that does not have any effect on people, making it safe and effective.

The vaccine, details of which were published in the journal Nature Medicine, produces a strong immune defence and completely protects mice and non-human 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.

Scott Weaver, Professor, University of Texas Medical Branch

Chikungunya is a mosquito-borne virus that causes a disease characterised by fever and severe joint pain, often in hands and feet. Symptoms may include headache, muscle pain, joint swelling or rash.

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Live-attenuated vaccines that are made from weakened versions of a live pathogen typically offer rapid and durable immunity but reduced safety. On the other hand, the inability of inactivated vaccines to replicate enhances safety but often require several doses and boosters to be effective.

There may be a risk of disease with both of these vaccine types, either from incomplete inactivation of the virus or from incomplete or unstable weakening of the live virus that is only recognised when rare vulnerable individuals contract disease.

To overcome these tradeoffs, the researchers used the Eilat virus as a vaccine platform since it only infects insects and has no impact on people.

Also Read: In the Battle Against Mosquitoes, Why Does Delhi Always Lose?

The researchers used an Eilat virus clone to design a hybrid virus-based vaccine containing Chikungunya structural proteins.

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 candidate vaccine induced neutralising antibodies that lasted for more than 290 days.

The antibodies provided complete protection against Chikungunya in two different mouse models.

In non-human primates, the vaccine 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 study said.

(With inputs from IANS)