Why the malaria vaccine breakthrough in Africa is historic

While not perfect, the vaccine is among the biggest steps forward in the fight against malaria espeically in Africa, home to most of the world’s 200 million-plus cases and 400,000 deaths per year
These are some of the poorest countries, where the vector for the disease — mosquitoes — are hard to contain due to endemic hygiene issues (AP) PREMIUM
These are some of the poorest countries, where the vector for the disease — mosquitoes — are hard to contain due to endemic hygiene issues (AP)
Updated on Oct 12, 2021 06:13 PM IST
Copy Link

On October 6, the World Health Organization (WHO) endorsed the world’s first malaria vaccine, and said it should be given to children across Africa.

The vaccine, known as Mosquirix, was developed by GlaxoSmithKline in 1987. Its approval was hailed as “historic” by WHO director-general, Tedros Adhanom Ghebreyesus, but there are still challenges. The vaccine is only about 30% effective, it requires up to four doses, and its protection fades after several months.

Still, scientists say the vaccine could have a major impact in the fight against malaria in Africa, home to most of the world’s 200 million-plus cases and 400,000 deaths per year.

High burden of disease

Nearly half the world’s population lives in tropical and subtropical areas — those which are at most risk of malaria transmission.

These are some of the poorest countries, where the vector for the disease — mosquitoes — are hard to contain due to endemic hygiene issues.

In African countries, in addition to these challenges, scarce resources and socioeconomic instability have hindered efficient malaria control activities.

Young children and pregnant women are usually the most vulnerable.

The United States (US) Centers for Disease Control (CDC) says that direct costs (for example, illness, treatment, premature death) have been estimated to be at least $12 billion per year. The cost — in lost economic growth — is likely to be many times more than that.

Major scientific challenge

Malaria has persisted for millennia. Caused by a parasite that is transmitted through mosquito bites, the disease has posed one of the hardest challenges for modern medicine.

According to the US CDC, malaria parasites have a complex lifecycle, and there is a poor understanding of the complex immune response to malaria infection.

Current efforts have hinged on vector control. Mosquitoes build rapid resistance to insecticides, almost putting the clock back on most vector-control methods.

Some antimalarial drugs (such as hydroxychloroquine and other quinine-based drugs) showed brief promise, but the parasite p falciparum has proven to be highly adept at mutating to become resistant.

The parasites are also genetically complex, producing thousands of potential antigens — the recognition of an antigen is critical in the design of vaccines. For instance, in the case of Sars-CoV-2, almost all vaccines at present target the S protein that has been easy to detect and remains a crucial component of the virus.

Unlike the diseases which currently have effective vaccines, exposure to malaria parasites does not confer lifelong protection, according to the CDC.

Acquired immunity only partially protects against future disease, and in many cases, people still become infected with the parasite. Malaria infection can persist for months without any symptoms of the disease.

The vaccine breakthrough

While not perfect, the vaccine is among the biggest steps forward in the fight against malaria.

Mosquirix, which goes by the development name RTS, S, is among more than a dozen vaccines in development. Large-scale studies of the vaccine began in Ghana, Kenya, and Malawi in 2019, including several hundreds of thousands of infants.

The vaccine ticks several boxes: It is easy to deliver, has a strong safety profile, leads to a significant reduction (30%) in deadly severe malaria, even when introduced in areas where insecticide-treated nets are widely used, and is cost-effective in areas of moderate to high malaria transmission.

For now, the vaccine has been approved for use in children up to two years old, and it is delivered in a regimen of four doses.

What next

Led by the WHO, leading funders of malaria vaccine development have developed a global strategy to accelerate the development of malaria vaccines: The Malaria Vaccine Technology Roadmap.

By 2030, they aim to achieve two specific objectives: Develop malaria vaccines with protective efficacy of at least 75% against clinical malaria, and create vaccines that reduce transmission of the parasite to substantially reduce the incidence of human malaria infection.

Enjoy unlimited digital access with HT Premium

Subscribe Now to continue reading
freemium
SHARE THIS ARTICLE ON
  • ABOUT THE AUTHOR

    Binayak reports on information security, privacy and scientific research in health and environment with explanatory pieces. He also edits the news sections of the newspaper.

Topics
Close Story
SHARE
Story Saved
OPEN APP
×
Saved Articles
Following
My Reads
Sign out
New Delhi 0C
Monday, December 06, 2021