The Chikungunya virus, transmitted by mosquitoes of the genus Aedes,
causes high fever, headaches, rashes and especially muscle and joint pain in 95%
of infected individuals. These symptoms disappear within 2-6 weeks in most
patients, although 5% to 30% of individuals exhibit clinical signs that may
persist for several months to years after the acute phase of the disease.
Researchers from the CEA-IMETI and their Swedish, Estonian, English and Spanish
collaborators within the ICRES [1] European consortium have begun the
construction of several vaccines to combat epidemics that regularly
emerge around the planet (see box). The researchers prepared several candidates,
including two attenuated vaccines based on genetically modified Chikungunya
strains, and a vaccine designed from synthetic DNA encoding a portion of the
viral proteins. These vaccines were tested one by one or in combination
in a rodent model, in collaboration with a Swedish laboratory. “We
observed a strong humoral immune response with antibody production, and a strong
cellular immune response”, states Pierre Roques. “Seven weeks after the vaccine
injection, a protective effect was measured by inoculating the wild virus in
animal models. It turns out that the protection against joint damage is very
effective when a booster vaccination is provided 3 weeks after the first
injection.” Two of these vaccines, evaluated as the most effective, will
soon be tested in non-human primates, whose immune system is close to humans. If
the results are conclusive, clinical trials could begin as soon as 2015.
Chikungunya: the geographic expansion of epidemic foci is feared, especially in the United States
Pierre Roques, virologist in the immuno-virology team at the CEA-IMETI
“We
recall the Chikungunya epidemic of 2005, which struck the islands of
the Indian Ocean, in particular Réunion with its hundreds of thousands
of cases, which resulted in a major economic crisis. Formerly confined
to Africa and South Asia, new epidemic outbreaks reflect an accelerated
dispersion of the virus since 2007. In the French Antilles, the
appearance at the end of 2013 of the first cases of Chikungunya and its
dispersion in the Caribbean islands up to Guyana suggests an attack on
the American continent, with major implications for public health.”
[1] Integration of Chikungunya research