Vaccine shows promise against chikungunya

An investigational vaccine using non-infectious virus-like particles demonstrated protection against chikungunya virus, according to data published in The Lancet.

“Since 2006, the virus has caused outbreaks of the disease where it had never been previously reported, including Italy, France, and most recently, the United States,” Julie Ledgerwood, DO, chief of the clinical trials program in the vaccine research center at the National Institute of Allergy and Infectious Diseases, said in a press release. “Currently, we have no licensed vaccines or approved drugs for this debilitating infection, which causes fever and intensely painful, severe arthritis.”

Julie Ledgerwood

The vaccine contains virus-like particles (VLP) that are composed of outer structural proteins of the West African strain 37997. Earlier research conducted in rhesus macaques demonstrated that the vaccine provided protection against the infection.

In this phase 1 trial, 25 healthy volunteers aged 18 to 50 years received one of three doses of the vaccine at weeks 0, 4 and 20. The researchers measured the chikungunya-neutralizing antibodies in the blood sera at regular intervals. The vaccinations were well tolerated and no serious adverse events or inflammatory side effects were reported. Four participants had mild-to-moderate vaccine-related effects: transient alanine aminotransferase increases and transient neutropenia.

Most participants demonstrated an immune response after the first vaccination, even with the lowest dose of the vaccine. After the second vaccination, all dose groups developed high antibody levels. The antibodies were also long-lasting and could be detected in all participants 6 months after the last vaccination.

According to Ledgerwood, the antibody levels among the participants 11 months after vaccination were comparable to those seen in people who had recovered from a natural chikungunya infection. In addition, the vaccine also generated antibodies against multiple genotypes of the virus.

“Such 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,” Ledgerwood said. “This same approach could also be applied to the production of vaccines against a range of viruses related to chikungunya that cause encephalitis.”

In an accompanying editorial, Ann Powers, PhD, of the CDC’s Division of Vector-borne Diseases, said although it may be a good vaccine option, there is concern about whether a vaccine for a vector-borne virus will be licensed, as the market for such vaccines may not be large enough to justify the investment to develop it.

“The cost of development of a vaccine — from preclinical studies to vaccine registration — is estimated to be $200 million to $500 million,” Powers wrote. “Yet, even with this need for substantial funding, vaccines are still the most cost-effective strategy for disease prevention. In view of the burden of chikungunya outbreaks, which have affected up to 63% of local populations in a matter of months, the continued development of this VLP vaccine candidate, along with other vaccine options, should be encouraged.”

For more information:

Chang L. Lancet. 2014;doi:10.1016/S0140-6737(14)61185-5.

Powers A. Lancet. 2014;doi:10.1016/S0140-6736(14)61290-3.