Malaysia is facing its
largest dengue outbreak ever, with 201 deaths so far in 2015, with the number
of fatalities rising sharply. There were 215 deaths in the whole of 2014, with
92 in 2013, and 35 in 2012.
In addition to the
increased number of cases, doctors are seeing different types of symptoms,
which raises the alarming possibility that the virus is becoming even more
deadly and difficult to control.
“We are seeing people
present with liver failure and meningitis; things that have not seen before
with dengue,” said Doctor Jeyaindran Sinnadurai, the deputy director general of
health at the ministry. “There is always the chance that a virus may have changed
in some way.”
A global concern
Incidences
of dengue have increased 30-fold in the last half century, according to the
World Health Organization (WHO), and half the world’s population is now at
risk. In Asia alone, where dengue is endemic in many countries, the economic
cost of the disease is estimated at about US$2 billion a year. That figure does
not include the costs of fogging and other means of killing the mosquito, which
form the backbone of efforts to control an illness for which there is no cure.
Dengue is
carried by the female Aedes mosquito, which has distinctive white stripes on
its body and legs and tends to bite early in the morning or at dusk. Many
infected people think they have a terrible bout of flu, because the symptoms
are quite similar. But the exhaustion, fever and joint pain that accompany
dengue are far worse. The worst-case scenario is that the victims develop
hemorraghic fever, which can be deadly.
Aside
from a saline drip to boost patients’ platelet count there is no treatment, and
because there are four types of dengue virus, people can get the disease more
than once. Malaysian officials say repeat infections may explain why symptoms
are becoming more severe and deaths are rising.
Searching for a vaccine
Doctors in
Malaysia are required to notify the Health Ministry if they identify a case of
dengue, which was discovered in the 18th century as global trade fueled the
development of busy ports, creating the perfect breeding ground for the Aedes
mosquito. In dengue hotspots, banners alert residents to an outbreak. Once a
case is confirmed, government workers are called in to spray a fog around the
neighborhood to kill off the mosquitoes. Doctors are also provided with rapid
detection kits to ensure a dengue diagnosis is made as quickly as possible.
Doctor
Lam Sai Kit, a research consultant at the University of Malaya, has been
tracking dengue for 40 years. He is skeptical about whether fogging and the
other control measures are truly effective, given the continued spread of the
disease. Lam believes a vaccine, when combined with the existing efforts, would
provide a huge boost to curbing the advance of the virus.
“I do not
think methods based on vector control (are) the answer or the solution,” Lam
told IRIN. “If they are effective, then why are we facing the present
situation? At best, they are fire-fighting measures.”
With WHO
aiming to cut the incidence of dengue by at least 25 percent and mortality by
at least half by 2020, a number of companies are attempting to create a
vaccine. French pharmaceutical giant Sanofi-Pasteur is the most advanced. It
recently concluded the third phase of clinical trials for a dengue vaccine that
it’s been working on for more than 20 years. The trials involved thousands of
children in Asia and South America and showed the vaccine provided protection
against all four types of the virus – at varying levels of efficacy. Among
young people aged between nine and 16, the vaccine reduced hospitalization by
80 percent and incidence of severe dengue by 93 percent.
Malaysia’s
Dr. Jeyaindran says the government hasn’t yet made a decision on the vaccine
but is working closely with WHO on the data. Given the sharp increase in
deaths, however, it has drawn up a new set of medical guidelines to help
doctors identify the most at-risk patients. Release of the new guidelines is
expected in the next couple of weeks. The additional data will also help them
understand why some people suffer more serious symptoms.
WHO said
the results were “consistent and encouraging,” but expressed some concern at an
apparent increased risk of hospitalization and severe dengue among children
under nine who received the vaccine. Sanofi-Pasteur hopes to secure regulatory
approvals from some of the worst-affected countries by the end of this year and
has sufficient production capacity to produce one billion doses over the next
decade.
But even
the vaccine won’t be a silver bullet, according to Baptiste De Clarens, general
manager for Sanofi-Pasteur in Malaysia, Brunei and Singapore.
“Singapore has
state-of-the-art vector control but still has outbreaks,” he said. “The
solution cannot be just one thing. The vaccine, vector control and public
awareness are the key elements that must work together to deal with dengue.
Asia Times
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