By Denise Roland
LONDON-- GlaxoSmithKline PLC's malaria vaccine, the world's most
advanced, has cleared its final scientific hurdle, but it could
still take up to a year before immunization programs begin in
sub-Saharan Africa.
The vaccine, which is aimed at young children, received a
positive scientific opinion from the European Medicines Agency's
Committee for Medicinal Products for Human Use on Thursday. But the
eventual rollout of the vaccine, called RTS,S, depends on a series
of decisions by stakeholders including the World Health
Organization, individual governments in sub-Saharan Africa, and
GAVI, the Vaccines Alliance, which is expected to subsidize the
immunization programs.
The WHO "may introduce certain restrictions or specifications
like [to] start in highly endemic areas, or...give it in
combination with other vaccines given in the same age bracket,"
said Moncef Slaoui, Glaxo's chairman of global vaccines. WHO
officials have also said the agency will consider how to ensure the
vaccine is used alongside other strategies such as the provision of
mosquito nets and antimalarial drugs.
Once the WHO has made a policy decision, which could take
several months, GAVI will consider its strategy for the vaccine.
While GAVI has not yet explicitly committed to funding the jab, it
is widely expected to do so.
Meanwhile, individual governments across sub-Saharan Africa will
determine their own immunization strategies.
The Glaxo vaccine, which is supported by the PATH Malaria
Vaccine Initiative and the Bill and Melinda Gates Foundation, is
the most advanced anywhere in the world by several years and the
first against any parasitic disease.
However, it is no magic bullet. In clinical trials, it was shown
to prevent around half of all cases of malaria in children given
their first shot aged 5 to 17 months, and a quarter of cases in
those aged 6 to 12 weeks when first inoculated. That is a much
lower level of protection than the 80% disease prevention from most
routine immunizations. Moreover, it loses effectiveness over time,
with the level of protection in toddlers dropping to just 36% after
four years, and is less potent against severe malaria, the
life-threatening form of the disease.
Nonetheless, scientists have said the vaccine offers a clear
benefit to children in sub-Saharan Africa because even this
relatively low level of protection could prevent hundreds of
thousands of cases of malaria every year. In 2013, around 437,000
African children died before their fifth birthday due to malaria,
most of which were in the sub-Saharan region, according to the
WHO.
The vaccine could also prove more effective when used in
real-world conditions, according to Dr. Slaoui. He said the
clinical trials will have likely played down the efficacy of the
vaccine since the trial sites were optimized for the prevention of
malaria through, for example, the provision of treated mosquito
nets that were frequently checked for holes.
"The reality is that the bed net is only effective if you have
used it," Dr. Slaoui said. "With vaccines, once immunized, your
protection is with you day and night. My expectation is the
effectiveness of this vaccine in real life conditions is going to
be substantially higher."
To determine the vaccine's real-world effectiveness, Glaxo has
recommended to the WHO that it be introduced in a "scientifically
driven way." That would mean first deploying the vaccine in areas
with health-care facilities that could monitor children after
immunization. "We would not support widespread immediate use. The
data will inform how best to use this vaccine," Dr. Slaoui
said.
The launch of immunization programs using Glaxo's vaccine, which
Dr. Slaoui hopes will happen by mid-2016, would mark the
culmination of nearly three decades of development efforts, with
research partners including the Walter Reed Army Institute of
Research in Silver Spring, Md. RTS,S has taken around twice as long
as a typical vaccine because the disease is caused by a complex
parasite.
Glaxo has already manufactured tens of millions of doses of the
vaccine in anticipation of its launch and is continuously producing
more at its facility in Belgium, according to Dr. Slaoui. "We are
preparing to be able to provide the vaccine when it's needed," he
said.
Glaxo is the only big pharmaceutical company with a malaria
vaccine, but a number of new approaches are being pursued by
nonprofits, government programs and universities, such as the
National Institute of Allergy and Infectious Diseases in the U.S.
and the University of Oxford. Sanaria Inc., a small biotech company
based in Rockville, Md., also is developing a malaria vaccine.
Glaxo has said it plans to sell the vaccine at a 5% premium to
the manufacturing cost and use the profits to fund further research
into vaccines for malaria and other neglected tropical
diseases.
Write to Denise Roland at Denise.Roland@wsj.com
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