LONDON -- Results from an early test
of a dengue vaccine suggest it isn't ideal, but scientists say the study
is still encouraging news in the global fight against the disease known
as "break-bone fever."
There is currently no treatment or vaccine for dengue,
which causes symptoms including fever, severe joint pain, headache and
bleeding. The mosquito-borne disease infects up to 100 million people
worldwide every year, mostly in Asia, Africa and Latin America.
The
research "provides the first evidence we could actually develop an
effective vaccine against dengue," said Orin Levine, a professor at
Johns Hopkins Bloomberg School of Public Health. He was not connected to
the study, published online Tuesday by the journal Lancet.
"This is a milestone, but we're not there yet," he said.
Larger
studies in about 30,000 people are now underway and should provide more
information about the effectiveness of the vaccine made by Sanofi
Aventis SA. Other dengue vaccines are being developed but Sanofi's is
the furthest along.
The Sanofi vaccine was
tested in more than 3,600 Thai children ages 4 to 11. More than 2,400
got three injections of the vaccine six months apart while about 1,200
got a rabies vaccine or a dummy shot. The study was paid for by Sanofi.
During
about two years of follow-up, there were 134 dengue cases, including
five severe cases. In the vaccine group, about 3% got dengue, compared
to about 4% in the group that didn't get the shot. The difference wasn't
big enough to suggest any benefit from getting the vaccine.
Scientists
said the vaccine seemed partly effective against three of the four
viruses that cause dengue and no unusual side effects were reported. The
study took place during an outbreak of mostly type 2 dengue, which
causes the most serious disease, but the vaccine didn't work against
that kind.
"It's not exactly a slam dunk,"
said Scott Halstead, a senior scientific adviser for the Dengue Vaccine
Initiative, who wrote an accompanying commentary. He said Sanofi might
need to consider reformulating the vaccine or creating separate shots
for each type of dengue.
Joachim Hombach, a
dengue expert at the World Health Organization, said it was encouraging
that the vaccine appeared safe. "But the public health value of this
vaccine remains to be demonstrated," he said.
Associated Press