— U.S. researchers have developed a prototype vaccine that protects
monkeys and mice against the emerging chikungunya virus, a major step
toward the production of a vaccine for humans. Human trials could begin
later this year.
Chikungunya is a mosquito-borne virus that first appeared on
in 2005 and has spread to more than 18 countries, infecting millions.
It is characterized by rash, a high fever and its most distinctive
characteristic, a severe arthritis that can persist for years. There
are currently no effective treatments and no preventive measures for
the virus, and health authorities fear it could cause a pandemic.
Public health authorities fear that the virus will
spread more widely because it has adapted to the Asian tiger mosquito,
which survives in temperate climates and is widespread. Increases in
global travel and climate change may also encourage its spread,
according to Dr.
To attack the problem, virologist
vaccines against hepatitis B and human papillomavirus. They produced a
so-called virus-like particle that contains the outer protein shell of
the virus — which allows it to be recognized by the immune system — but
not the viral genetic information, preventing it from replicating.
The team reported Thursday in the online version of
the journal Nature Medicine that immunization of rhesus macaque monkeys
with the particles provided full immunity when the animals were
subsequently exposed to the live virus.
Antibodies against the virus were then isolated from
the monkeys and injected into immunodeficient mice. The antibodies
protected the mice from a subsequent exposure to a normally lethal dose
of the virus.
In addition to human trials of the new vaccine,
Nable and his team plan to study whether a similar approach could be
used to protect against the related western and eastern equine
encephalitis viruses found in
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