New chikungunya vaccine

Subject: Science and technology

Section: Health

Concept:

A new clinical study shows promising results of a Phase III chikungunya vaccine trial, the first time the shot has been tested in humans.

Chikungunya

Chikungunya is a mosquito-borne viral disease caused by the chikungunya virus (CHIKV) that causes fever and severe joint pain.
The disease was first recognized in 1952 during an outbreak in southern Tanzania.
It is a ribonucleic acid (RNA) virus that belongs to the alphavirus genus of the family Togaviridae.
The name “chikungunya” derives from a word in the Kimakonde language of southern Tanzania, meaning “to become contorted”, and describes the stooped appearance of sufferers with joint pain (arthralgia).
Chikungunya is transmitted to humans by the bites of infected female mosquitoes – Aedes aegypti and Aedes albopictus.

Treatment and vaccines

The clinical management includes addressing fever and joint pain.
There is no specific antiviral drug treatment for CHIKV infections.
There is no commercial vaccine available to protect against chikungunya virus infection.

Global scenario

Tropical regions currently see the highest rates of the virus, with Paraguay, Brazil, Bolivia and Thailand most affected.
Outbreaks have been ongoing in Congo, Sudan and Kenya since 2018, but cases have been relatively low.
However, a major 2013 outbreak of chikungunya in South America led to over 1 million infections in just a few months.
While death rates were low, around 52% of infected people experienced severe joint pain lasting months.
Studies suggest the disease caused the loss of 150,000 disability-adjusted life-years in 2014 alone.
The measurement represents the loss of the equivalent of one year of full health.

The new vaccine:

The vaccine contains a modified, live version of the chikungunya virus that can replicate in the body without causing severe illness.
Live vaccines closely mimic natural infections, triggering a robust immune response that provides long-lasting and broad protection.
Other live vaccines:
- measles, mumps and rubella (MMR combined vaccine), smallpox and yellow fever are all live vaccines.
- Risks associated with live vaccines:
- Rare possibility of the weakened virus reverting to a more virulent form.