For the past 30 years, Moncef Slaoui has been
working on a vaccine for malaria; one of the world’s most persistent and
deadly diseases. The European Medicines Agency has approved the world's first malaria
vaccine - meaning that it could be administered to children across
Africa within the next few years.
Around 585,000 people die each year from the
disease, most of them children under five years of age. Up to 90% of
malaria deaths occur in sub-Saharan Africa, where the economic impact is
huge. UN estimates put the cost to Africa at $12 billion per year.
In April, the results of a huge five-year trial
across seven African countries showed that an experimental vaccine,
RTS,S, developed by GSK and the Gates Foundation-backed PATH Initiative
had a moderate, but positive impact on cases of malaria in children and
infants. On Friday, the European Medicines Agency gave its approval to
the RTS,S vaccine for children, setting in motion a process that could
put the vaccine into the field by the middle of next year.
“I was crying,” Slaoui, now GSK’s chairman,
global vaccines, says. “I was born in Africa, in a country which doesn’t
have malaria — Morocco. But it’s a country where your siblings die
[while you’re growing up]. It’s very impactful.”
The trial stage was conducted by hundreds of
African and international researchers in the field across 11 sites in
Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania. Its
results, published in the Lancet, showed that it was around 30%
effective in infants and 40% in toddlers.
“There is certainly room for improvement, but
when you translate these numbers into the number of cases they prevent
in the population, one really realizes the extent of how impactful this
vaccine could be,” Slaoui says.
“It’s an enormous impact, when you know that
there are 30 million infants born every year in sub-Saharan Africa,
500,000 of which will die of malaria.”
A second generation vaccine is already in development.
Concerted
international efforts by organisations including the Global Fund to
Fight AIDS, Tuberculosis and Malaria, have had a meaningful impact in
Africa. The distribution of hundreds of thousands of bed nets, combined
with insecticide spraying and low-cost treatment reduced mortality rates
in Africa by 54% between 2000 and 2013 — accounting for more than 4
million lives saved — but a vaccine has been a white whale for global
health professionals and the pharmaceutical industry.
Stopping a parasite
The challenge has been largely technical. The
malaria parasite is, as David Kaslow, vice-president of product
development at PATH, says: “a really wily pathogen. What we’re talking
about here is not some small virus or bacteria. This is a parasite… They
evolved with humans for millennia.”
When a mosquito carrying the Plasmodium falciparum parasite
bites a human, it takes a few minutes for the pathogen to reach the
liver. There, it takes five more days to transform into another
configuration and multiply, finally infecting the red blood cells and
causing the illness.
For decades, researchers had been trying to make
antibodies against the first stage of the parasite, in an attempt to
prevent it from reaching the liver. Next, they tried to stimulate the
creation of antibodies against the final stage. It was only as
immunology improved throughout the 1980s and 90s that researchers,
including Slaoui, were able to work on attacking the parasite in its
middle stage, in the liver.
“This milestone tells us that it’s biologically
and technically feasible to create malaria vaccines, and that we should
continue to invest in vaccine R&D to develop the next generation of
malaria vaccine,” Kaslow says.
“This now provides a foundation from which to
build on. We’re no longer starting from 0% efficacy. We’re starting from
more than 50% efficacy. That’s a much better place to start for the
next generation of vaccines. And we do have a relatively rich pipeline
of next generation vaccines that could have higher efficacy… When the
goal is elimination and ultimately eradication, this gives us at least a
foothold in developing that next generation vaccine. This gives us some
very important clues as to go about doing it.”
Kaslow is quick to point out that the qualified
success of the RTS,S vaccine is an important milestone, it is not a
silver bullet.
“Despite good bed net coverage, despite good case
management, despite indoor spraying, there are 584,000 deaths due to
malaria, 198,000,000 cases of malaria every year,” he says. “We need new
tools to combat this wily parasite. We just cannot let our foot off the
gas on this, because it will come back with a vengeance. Lest anyone
think the malaria problem is solved. It is not. We have got a way to
go.”
The vaccine, named Mosquirix, was given the green light on Friday after more than 30 years of research, detailed in 230,000 pages of data. It now means that the vaccine will be examined by the World Health Organisation and, if approved, could be administered to children across Africa within the next few years.
"It's massively significant," said Allan Pamba, vice president for pharmaceuticals in East Africa for GlaxoSmithKline (GSK), which has spent more than $356 million (£230m) to date on finding a vaccine. GSK expects to invest a further $200 to $250 million until development is completed.
In January 2001, GSK and PATH Malaria Vaccine Initiative, with grant monies from the Bill & Melinda Gates Foundation to PATH, entered into a public-private partnership to develop a vaccine. PATH has invested more than $200 million, much of it from the Gateses.
The WHO has said it may give a policy recommendation by the end of the year; African authorities will then take their decisions about how and where they would implement a vaccination programme.
But, given that an estimated 600,000 people die from malaria every year - 90 per cent in sub-Saharan Africa - Dr Pamba said the health ministers he spoke to on a regular basis were eagerly awaiting the arrival of a vaccine.
"Pretty much every health minister I speak to has had malaria," said Dr Pamba, who was born in Kenya and now works between Nairobi and London. "They all want to know when it will be ready."
Mosquirix, whose scientific name is "RTS,S" has been designed to prevent malaria caused by the Plasmodium falciparum parasite, which is most prevalent in sub-Saharan Africa. It is the first vaccine to be developed which counters the effects of a parasite.
The vaccine is designed to prevent the parasite from infecting, maturing and multiplying in the liver, after which time the parasite would re-enter the bloodstream and infect red blood cells, leading to disease symptoms.
The developers carried out a trial programme involving more than 16,000 young children, conducted by 13 African research centres in eight African countries - Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique, Nigeria, and Tanzania.
Two groups of children were tested: infants aged from six to 12 weeks, and young children aged five to 17 months.
Data from the trial programme demonstrate that over the first 18 months following three doses of RTS,S, malaria cases were reduced by almost half in the older group. With infants, cases dropped by 27 per cent.
Sir Andrew Witty, CEO of GSK, said: "Today's scientific opinion represents a further important step towards making available for young children the world's first malaria vaccine.
"While RTS,S on its own is not the complete answer to malaria, its use alongside those interventions currently available such as bed nets and insecticides, would provide a very meaningful contribution to controlling the impact of malaria on children in those African communities that need it the most."
