First malaria vaccine hits 1 million dose milestone — although it has its shortcomings

Earlier this week, Dr Kwaku Poku Asante from Ghana received the phone call that he consistently dreads. It was his son’s school. His child had a fever. “I’m not sure if it’s malaria,” he says, “but I’m concerned.”

Asante’s son is 14, so he is not in the risk group for children aged 5 and under. Yet in much of Africa, parents are terrified of a child’s fever, which could indicate malaria.

The disease also defines much of Asante’s professional life, as director of the Kintampo Health Research Center. “I’ve seen many, many, many, many children in the hospital,” he says. “Sometimes [they] come in twitching. Sometimes they come in with severe anemia. Sometimes they come with vomiting.”

And sometimes these children die. In 2020, the World Health Organization counted nearly a quarter of a billion cases of malaria in children and adults, mainly in Africa, resulting in 627,000 deaths. For years, the best protective measures have been preventive measures: insecticide-treated bed nets, anti-malarial pills, closing windows at night, and reducing mosquito habitat.

“With all these interventions, there came a time when we reached a plateau,” says Dr. Rose Jalang’o, who works with the Ministry of Health’s National Vaccines and Immunization Program in Kenya. “At that time, we needed new tools to further reduce the burden of malaria.”

Such a new tool came on the market last fall when the WHO authorized the introduction of a malaria vaccine – the first ever against a parasitic disease – in Ghana, Kenya and Malawi. And now a milestone has been reached: In April, 1 million children received at least one dose.

The timing of the vaccine’s launch is critical. During the pandemic, the mosquito-borne disease saw an increase in cases and deaths.

“Wow, this is a total game changer,” said Jalang’o, who is coordinating malaria vaccination in Kenya.

The vaccine has been a long time coming. It has taken more than 30 years to develop, in part because “the malaria parasite is so complex,” said Dr Mary Hamel, who leads the malaria vaccine team at WHO. The approximately 5,000 genes (compared to only about 30 for SARS-CoV-2) have allowed our immune system to evade a variety of adaptations. The vaccine combines an immune stimulant and a protein that “completely coats the outer membrane of the first phase of the malaria parasite, called the sporozoite,” explains Hamel.

There are concerns about the new vaccine’s effectiveness — and its demanding schedule. It requires 3 or 4 doses by age 2 – a challenge for parents. In addition, the vaccine only reduces hospitalizations for severe malaria by 30%, and there is a large margin of error on that figure. With three doses, efficacy may decrease, although children at a vulnerable age receive some degree of protection.

But that benefit can be extended. A fourth dose, Hamel says, extends protection to 3 1/2 or even 4 years. In addition, vaccination before the high malaria transmission season provides that extra protection at a crucial time.

“Having a malaria vaccine has the potential to reduce the number of deaths from malaria, so I think it’s a really big deal,” says Jalang’o. She says community members have told her that their children are getting less malaria: “For example, a mother tells you that a child who has been vaccinated has only 1 or 2 malaria episodes per year, compared to 4 or 5 cases in the past. ”

“You know, it’s not perfect,” says Dyann Wirth, a geneticist at the Harvard TH Chan School of Public Health. “Would I want a vaccine that is 100% effective and can be given easily in one dose? Absolutely. But that’s not the reality.” Wir chairs an independent malaria advisory group at WHO, noting: “The vaccine offers some protection. I think there’s no justification for not using it. It’s important that it’s available to the population that can get it.” taking advantage.”

In addition, health professionals on the ground say this vaccine is not intended to replace other measures such as mosquito nets. It’s another layer of protection.

And with other vaccines and preventive treatments in the works, Dr. Asante optimistic. “Right now,” he says, “if there’s a vaccine, we can only improve it over time.”

Copyright 2022 NPR. For more information, visit https://www.npr.org.

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