New vaccine to offer protection against chikungunya

In a major breakthrough, the first human trial of a new vaccine developed using non-infectious virus-like particles (VLP) is likely to offer protection against chikungunya virus, a study has reported.

The phase 1 trial included 25 healthy volunteers aged 18 to 50 in the US. Each volunteer received one of three different doses of injected vaccine at weeks 0, 4, and 20.

Chikungunya neutralising antibodies in the blood of recipients were measured at regular intervals. Vaccinations were well tolerated with no serious adverse events reported, and no evidence of any inflammatory side effects, the study, published in the prestigious journal Lancet, added.

An immune response in the form of neutralising antibodies was detected in the majority of recipients after the first vaccination. Even the lowest doses of the vaccine were effective, and following the second vaccination, all recipients in all dose groups had developed high levels of antibodies.

Importantly, antibodies were long-lasting and could be detected in all participants six months after their last vaccination. "Eleven months after vaccination, antibody levels were comparable to those seen in people who had recovered after natural chikungunya infection, suggesting that the VLP vaccine could provide long-term protection against the virus," explained study leader Julie Ledgerwood from the US National Institute of Allergy and Infectious Diseases, National Institutes of Health.

The vaccine also generated antibodies against multiple genotypes of the virus, suggesting that it could be effective against any strains of the virus. A mosquito-borne infection, chikungunya virus has become a growing public-health threat that has affected millions of people in Africa, Asia and Europe.

In recent months, it has been spreading throughout the Americas. "A VLP vaccine should be relatively economical to produce in large quantities because it needs minimal containment as live virus is not required for production," Dr Ledgerwood hoped.