New vaccines create hope to eradicate Malaria

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Throughout her childhood, Miriam Abdullah was carried in and out of hospitals, her thin body plagued by fever and ravaged by malaria. She got so sick so often that her constant treatments drained her parents, who also took care of her many siblings, both financially and emotionally.

“At one point, even my mother gave up,” recalled Abdullah, now 35.

In Nyalenda, the impoverished community of Kisumu, Kenya, where Abdullah lives, malaria is endemic and widespread. Some of his friends developed meningitis after being infected; one died. “Malaria has really plagued us as a country,” she said.

There are tens of millions of horror stories like Abdullah’s, handed down from generation to generation. But now change is coming: Malaria is the rare global health scourge that experts are optimistic about — so much so that some have started talking about eradicating the disease.

“I think there’s a lot of room for optimism,” said Philip Welkhoff, director of malaria programs at the Bill and Melinda Gates Foundation. “By the end of this decade, we could really give a push that takes us to zero.”

China and El Salvador were certified malaria-free last year, and the six countries in the Greater Mekong region, including Vietnam and Thailand, have reduced cases by about 90%. 25 countries are expected to have eliminated malaria by 2025.

Most infections occur in Africa today. Even there, despite limitations imposed by the coronavirus pandemic, nearly 12 million more African children received preventive malaria drugs in 2020 compared to 2019.

But it’s the arrival of two new vaccines that portend a big change. The first, called Mosquirix, took 35 years to make. It was approved by the World Health Organization last year and may be distributed at the end of next year.

A more powerful malaria vaccine, developed by the Oxford team that created AstraZeneca’s Covid-19 vaccine, could take a year or two. Many experts believe that this formulation, which has been shown to be up to 80% effective in clinical trials, could transform the fight against malaria.

There are more options on the horizon, including an mRNA vaccine being developed by German company BioNTech; monoclonal antibodies that can prevent malaria for six months or more; mosquito nets coated with long-lasting insecticides or chemicals that paralyze mosquitoes; as well as new ways to capture and kill mosquitoes.

“It’s an exciting time,” said Dr. Rose Jalang’o, who led a pilot trial of the Mosquirix vaccine in Kenya, where it was given to children alongside other immunizations.

But getting to a malaria-free world will require more than promising tools. In many African countries, the distribution of vaccines, medicines and bed nets requires overcoming numerous challenges, which include rough terrain, other urgent medical priorities and misinformation.

While funding for malaria programs is more generous than for many other diseases afflicting poorer nations, resources are still limited. Money devoted to one approach often leads funders to neglect others, fueling competition and sometimes rancor.

Mosquirix cost more than $200 million to develop over 30 years, but its effectiveness is roughly half that of Oxford’s vaccine, called R21. The first doses of Mosquirix will not be delivered to African children until late 2023 or early 2024. Supply will be severely limited for a variety of reasons, and is expected to remain so for years.

R21, the second vaccine, appears to be more potent, cheaper and easier to manufacture. And India’s Serum Institute is poised to produce over 200 million doses of R21 a year.

Some malaria experts note that, given the urgent need, the world needs every option possible. But others fear that every dollar spent on Mosquirix is ​​now a dollar less to develop other tools.

“Existing malaria control measures are already underfunded,” said Dr. Javier Guzman, director of global health policy at the Center for Global Development in Washington. “I don’t want to be negative, but a new tool without additional funding basically means sacrifices and an opportunity cost.”

‘Progress too fast’

Malaria is one of the oldest and deadliest infectious diseases. Years of rapid progress in the fight stalled about a decade ago, leaving the balance in 2019 at 229 million new infections and 558,000 deaths.

While the Covid pandemic did not trigger malaria infections, as tuberculosis did, the pandemic reversed a slow downward trend in malaria deaths, which rose to 627,000 in 2020.

Almost all the lives lost to malaria are in sub-Saharan Africa, where about 80% of deaths occur in children under 5 years of age.

Many strategies to fight malaria are outdated, but still inaccessible to millions. Only about half of African children sleep under insecticide-treated bed nets, for example, and even fewer receive seasonal medications that prevent infection.

Malaria exacerbates social inequalities. It deprives children of the ability to fight other pathogens, strains health systems and devastates entire communities. A person with untreated malaria can remain sick for six months, giving mosquitoes the opportunity to spread the parasite to up to 100 other people.

The parasite destroys the body so quickly that when children are taken to hospital, many urgently need a blood transfusion. But blood is often in short supply in sub-Saharan Africa, and using a bag for a young child could mean that half or more will be discarded, said Dr. Mary Hamel, who leads the WHO’s malaria vaccine implementation programme.

“You see a child so pale and limp breathing so quickly, and he’s just lying in his crib — and there’s nothing you can do about it,” she said.

“Malaria has to be prevented; it progresses too fast,” he added.

Mosquirix, the first vaccine against any parasite, is a technical triumph. But its effectiveness, at about 40%, is much lower than scientists expected.

Ideally, the vaccine would be deployed alongside existing controls such as insecticide-treated bed nets and preventative medications, as data indicates where tools are most needed and provided by a robust workforce.

“If you combine it with the right tool, you can have a much greater impact,” said Dr. Thomas Breuer, director of global health at GlaxoSmithKline, which makes Mosquirix.

But in many African countries there is high distrust of vaccines. In one survey, about half of people in Niger and the Democratic Republic of Congo said they would not trust a malaria vaccine.

In addition, Mosquirix should be given in four doses, the first at 5 months of age and the fourth after 18 months of age. But few other vaccines are given to children older than 18 months, and many parents in Africa face huge logistical obstacles in getting children to a clinic.

limited resources

Compared to the billions of dollars invested in Covid vaccines, malaria funding is a pittance. The Gates Foundation spends about $270 million a year fighting the disease, not counting its contributions to the Global Fund to Fight AIDS, Tuberculosis and Malaria.

Scarcity of resources means that people – and organizations – end up choosing favorite strategies. Some argue that controlling mosquitoes is the logical course, while others encourage vaccines. Still others say that monoclonal antibodies are the way forward.

In such a highly competitive arena, Mosquirix does not emerge as the obvious winner.

“Implementing a tool that is expensive, and not so effective, with a short duration of action, may not be the best thing to do first,” said Dr. Scott Filler, head of malaria programs at the Global Fund, which supports more than half of malaria programs around the world.

The money might be better spent increasing the use of bed nets or ensuring people have access to basic primary health services, including malaria testing, treatment and screening, Filler said.

But other experts believe that, given the ravages of malaria, a vaccine with low efficacy is better than none.

“We have this vaccine that has been tested very extensively – more than any vaccine before approval,” said Michael Anderson, former director general of the UK Department for International Development who now leads MedAccess, a government-funded non-profit group. British.

The R21 cost less than $100 million to develop. If regulators are as quick and agile as they were with Covid vaccines, it could be authorized a few months after researchers submit final data later this year.

For many parents in Africa, a vaccine may not arrive in time. In Kisumu, Abdullah is eager to immunize her 2-year-old daughter, who once had malaria, against the disease that ruined her own childhood.

“I would give it to her right away,” she said. “In fact, I would do it before I even got the Covid-19 vaccine.”

Translated by Luiz Roberto M. Gonçalves

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