The first malaria vaccine hits the 1 million dose milestone, although it has its limitations

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

Asante’s son is 14, so he is not part of the high-risk group of children aged 5 or younger. However, parents across much of Africa are terrified of a child’s fever, which can signal malaria.

The disease also defines much of Asante’s professional life, as director of the Kintampo Health Research Center. “I have seen many, many, many, many children in the hospital,” she says. “Some time [they] gets into convulsions. Sometimes they come with severe anemia. Sometimes they come with vomit. ”

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

“With all these interventions, there has come a time when we have stabilized,” says Dr Rose Jalang’o who works with the National Vaccination and Immunization Program at the Ministry of Health in Kenya. “At that point, we needed new tools to further reduce the burden of malaria disease.”

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

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

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

The vaccine has been around for a long time. It took over 30 years to develop, in part because “the malaria parasite is so complex,” says Dr Mary Hamel, who leads the WHO’s malaria vaccine team. Its roughly 5,000 genes (compared to just about 30 in SARS-CoV-2) have enabled it to evade our immune system through a variety of adaptations. The vaccine combines an immunostimulant 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 new vaccine’s effectiveness and its demanding schedule. Requires 3 or 4 doses by age 2: a challenge for parents. Furthermore, the vaccine only reduces hospital admissions for severe malaria by 30%, and there is a large margin of error on this figure. With three doses, efficacy may decrease, although children gain some protection at a vulnerable age.

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

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

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

Additionally, health workers in the field say this vaccine is not intended to replace other measures such as mosquito nets. It’s an extra layer of protection.

And with more vaccines and preventative treatments in the pipeline, Dr. Asante is optimistic. “At this point,” he says, “if there is a vaccine, we can only improve it over time.”

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