American researchers have developed a vaccine for chikungunya fever made from an insect-specific virus that does not have any effect on people, making the vaccine safe and effective.
The study indicated that the vaccine quickly produces a strong immune defence and completely protects mice and nonhuman primates from disease when exposed to the chikungunya virus.
The findings were published in journal of Nature Medicine.
"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 senior author Scott Weaver from the University of Texas Medical Branch at Galveston.
Chikungunya is a mosquito-borne virus that causes a disease characterised by fever and severe joint pain, often in hands and feet and may include headache, muscle pain, joint swelling or rash. Some patients will feel better within a week but many develop longer-term joint pain that can last up to years. Death is rare but can occur.
Traditionally, vaccine development involves tradeoffs between how quickly and safely the vaccine works.
The researchers used the Eilat virus as a vaccine platform since it only infects insects and has no impact on people. They 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.
The findings indicate that within four days of a single dose, the Eilat/Chikungunya 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 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.