A new study has revealed that a new vaccine developed using non-infectious virus-like particles (VLP) appears likely to offer protection against chikungunya virus.
According to the study, new vaccine consists of VLP composed of the outer structural proteins of the West African strain 37997 that would typically be seen by the immune system. These nanoparticles mimic the immune-stimulating effects of actual virus particles but cannot cause infection because they do not contain the genetic material of the virus. Earlier research in rhesus macaques showed that the candidate vaccine provided protection from infection.
Study leader Dr Julie Ledgerwood at the National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA said that chikungunya virusvirus has adapted itself to be transmitted by not only the Aedes aegypti mosquito that lives mainly in the tropics but also by the Asian tiger mosquito (Aedes albopictus) which is found in more temperate regions such as Europe and the Americas. Since 2006, the virus has caused outbreaks of disease where it had never been previously reported, including Italy, France, and most recently, the USA.
The study found that vaccinations were well tolerated with no serious adverse events reported, and no evidence of any inflammatory side effects. Four participants reported mild to moderate side effects related to the treatment; transient alanine aminotransferase increases (an enzyme present in liver and heart cells that is elevated when these organs are damaged) and transient neutropenia (low white blood cell count that leaves individuals vulnerable to infections.)
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 6 months after their last vaccination.
The scientists said that 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. The vaccine also generated antibodies against multiple genotypes of the virus, suggesting that it could be effective against any strains of the virus.
