The first malaria vaccine to reach a million doses – despite its shortcomings

Earlier this week, Dr. Kwaku Boko Asante from Ghana received a phone call he constantly feared. It was his son’s school. His child had a fever. “I’m not sure if it’s malaria or not, but I’m upset,” he says.

Asante’s son is 14 years old, so he is not in the high risk group of children aged 5 and under. However, in most parts of Africa, parents are terrified of the fever of young children, which may indicate malaria.

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

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 preventative measures have been preventative – insecticide-treated bed nets, antimalarial pills, closing windows at night, and minimizing mosquito habitats.

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

Such a new tool arrived last fall when the World Health Organization authorized the release of a malaria vaccine — the first ever against a parasitic disease — in Ghana, Kenya and Malawi. And now it’s reaching a milestone – one million children have received at least one dose as of April.

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

“Wow, you have completely changed the rules of the game,” says Galango, who coordinates malaria immunization efforts in Kenya.

The vaccine has been around for a long time. It has taken the disease more than 30 years to develop, in part because “the malaria parasite is so complex,” says Dr. Mary Hamel, who leads the malaria vaccine team at the World Health Organization. And 5,000 or so genes (compared to only about 30 for SARS-CoV-2) have allowed it to evade our immune system through a variety of adaptations. Hamel explains that the vaccine combines an immunostimulant with a protein that “completely covers the outer membrane of the first stage of the malaria parasite, which is called a sporozoite.”

There are concerns about the effectiveness of the new vaccine — and its demanding schedule. Requires 3 or 4 doses at the age of two – a challenge for parents. Moreover, the vaccine only reduces hospital admissions for severe malaria by 30%, and there is a large margin of error in this number. With three doses, effectiveness can wane, although children gain some measure of protection at a weak age.

But this benefit can extend. A fourth dose, Hamel says, extends protection until age 3 1/2 or even 4 years. Moreover, vaccination before the high malaria transmission season provides that additional protection at a critical time.

“Getting a malaria vaccine has the potential to reduce malaria-related deaths, so I think it’s a really big problem,” Galango says. She says community members have told her that their children have less malaria: “For example, a mother tells you that a vaccinated child may have only one or two episodes of malaria a year compared to 4 or 5 cases in her past.”

“You know, it’s not perfect,” says Diane Wirth, a geneticist at Harvard T.H. Chan School of Public Health. “Do I want a vaccine that is 100% effective and can easily be given in one dose? Sure. But that’s not the reality.” Wirth heads an independent advisory group on malaria at the World Health Organization and notes that “the vaccine shows some protection. I think not using it would not be justified. It is important that it is available to a population that could benefit.”

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

With vaccines and other preventative treatments in place, Dr. Asante is optimistic. “At this point, if there is a vaccine, we can only improve it over time,” he says.

Copyright 2022 NPR. To learn more, visit https://www.npr.org.

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