Chikungunya vaccine may be around the corner

An experimental vaccine against chikungunya virus infection has shown promise, according to reserachers at the National Institute of Allergy and Infectious Diseases (NIAID).

The chikungunya vaccine candidate, which is being developed using non-infectious virus-like particles (VLP), has protected monkeys and mice against chikungunya virus.

Currently, there is no vaccine or treatment available for chikungunya virus infection.

Maryland, US-based vaccine maker Novavax has recently formed a joint venture with Cadila Pharmaceuticals to develop vaccines against chikungunya and dengue fever based on Novavax’s virus-like-particle (VLP) vaccine technology.

Scientists in NIAID’s Vaccine Research Center (VRC) identified the proteins that give rise to chikungunya VLPs, to develop the chikungunya vaccine.

The VLPs mimic actual virus particles but cannot cause infection, so  they can be used safely as a vaccine to elicit immune responses.

The researchers immunized rhesus macaques with the VLPs, waited 15 weeks before exposing the animals to chikungunya virus, and observed that the vaccine provided complete protection from infection.

When the group found that antibodies were responsible for immune protection, they transferred antibody-containing serum from the vaccinated macaques to mice with deficient immune systems.

The mice then were exposed to a lethal dose of chikungunya virus, but the immune serum protected them from infection.

“This virus-like particle vaccine provides a promising way to protect against an emerging infectious disease threat,” stated VRC Director Gary Nabel, M.D., Ph.D in an official release.

This same approach could possibly extend to viruses related to chikungunya that cause fatal diseases such as encephalitis, Dr Nabel added.

There are two VLP vaccines for other diseases approved by the Food and Drug Administration: one for hepatitis B and one for human papillomavirus.

NIAIDs study marks the first time that scientists have used VLPs in a vaccine to protect against chikungunya virus, which is in the genus Alphavirus.

The group plans to determine whether VLPs will work against other alphaviruses, such as Western and Eastern equine encephalitis virus found in the United States and o’nyong-nyong virus found in Africa.

Researchers now plans to seek approval for clinical trials to further evaluate the safety and efficacy of the chikungunya vaccine in humans.

Chikungunya virus, a mosquito-borne pathogen, has infected millions of people in Africa and Asia and causes debilitating pain, researchers at the National Institutes of Health have found.

Chikungunya virus (CHIK) is a member of the Alphavirus genus of the family Togaviridae. The alphaviruses consist of 30 species of arthropod-borne viruses, which are further subgrouped into seven serocomplexes based on serological data.

CHIK was first isolated from the serum of a febrile patient during a dengue epidemic that occurred in the Newala district, Tanzania, in 1953.

Chikungunya returned in 2004 and 2005 and has since spread to nearly 20 countries to infect millions.

Chikungunya infection is often not fatal but it causes debilitating pain and exhaustion and can have long-term or even permanent effects.

Increases in global travel and trade, and possibly climate change, may be contributing to the spread of disease-carrying mosquitoes into new areas, stated NIAID Director Anthony S. Fauci, M.D.

In 2005 chikungunya virus struck Bangalore and infected several hundreds of patients across India.

Finding safe and effective human vaccines for chikungunya virus and other insect-borne pathogens is an important global health priority, he added.

Investigators from Purdue University, the University of Texas Medical Branch at Galveston, and Bioqual, Inc., in Rockville, Md., collaborated with NIAID scientists on this study.

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses.

The National Institutes of Health (NIH)—The Nation’s Medical Research Agency—includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services.