The first malaria vaccine reaches the milestone of 1 million doses, although it has its shortcomings

Earlier this week, Dr. Kwaku Poku Asante of Ghana received the phone call he always fears. It was his son’s school. Her son had a fever. “I’m not sure if it’s malaria,” he says, “but I’m worried.”

Asante’s son is 14 years old, so he is not part of the high-risk group of children aged 5 and under. However, parents in much of Africa are terrified of a child’s fever, which can indicate malaria.

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

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

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

This new tool arrived last fall when the WHO authorized a vaccine against malaria, the first against a parasitic disease, to be deployed in Ghana, Kenya and Malawi. And now it has reached a milestone: 1 million children have received at least one dose in April.

The timing of the vaccine release is crucial. During the pandemic, mosquito-borne disease saw an increase in cases and deaths.

“Wow, this is a total game changer,” says Jalang’o, who is coordinating Kenya’s malaria vaccination effort.

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

There are concerns about the effectiveness of the new vaccine and its demanding timing. Requires 3 or 4 doses at 2 years, a challenge for parents. In addition, the vaccine only reduces hospital admissions for severe malaria by 30%, and there is a wide margin of error in this figure. With three doses, the effectiveness may decrease, even if children get a protective measure at a vulnerable age.

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

“Having a malaria vaccine has the potential to reduce the deaths associated with malaria, so I think it’s very big,” says Jalang’o. She says community members have told her that her children get less malaria: “For example, a mother tells you that a child who has been vaccinated can have only 1 or 2 episodes of malaria in a year, compared to 4 or 5 cases a year.

“You know, it’s not perfect,” says Dyann Wirth, a geneticist at Harvard TH Chan School of Public Health. “I would like a vaccine that is 100% effective and easily administered in a single dose? Absolutely. But that’s not the reality.” Wirth chairs a WHO-independent malaria advisory group and notes: “The vaccine shows some protection. I don’t think using it would be justifiable. It’s important that it be available to people who can benefit from it.”

In addition, health professionals in the field say that this vaccine is not intended to replace other measures such as mosquito nets. It is another layer of protection.

And with other vaccines and preventive treatments underway, Dr. Asante is optimistic. “At this point,” he says, “if there’s a vaccine, we can only improve it over time.”

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