WHO approves ‘revolutionary’ childhood malaria vaccine

The fight against malaria, one of the world’s worst diseases for decades, is likely to get much easier as the World Health Organization has approved the widespread use of a malaria vaccine developed by GlaxoSmithKline, the first to obtain such approval. The vaccine will be recommended for children in sub-Saharan Africa and other high-risk areas as a four-dose schedule from the age of 5 months.

Malaria is a mosquito-borne infection caused by at least five species of the Plasmodium parasite. Most infections come from Plasmodium falciparum and Plasmodium vivax, the former causing most cases in Africa. The first symptoms of malaria tend to be mild and include fever, headache, and chills, but P. falciparum malaria can cause severe organ damage and death if left untreated, especially in young children.

Malaria cases and deaths have decreases in recent decades, through dedicated mosquito control and treatment programs. But there were still 229 million estimated cases worldwide in 2019, along with an estimated 400,000 deaths, just one second after tuberculosis for a single infectious disease (covid-19 has since outmoded malaria and probably tuberculosis in the past two years). The precarious progress against malaria is further threatened by the emergence of insecticide resistance in women. Anopheles mosquitoes, vectors of the disease.

The lingering threat of malaria has made the prospect of a childhood vaccine all the more enticing. But developing a vaccine against a complex organism like a parasite has proven to be much more difficult than it has been for simpler bacteria and viruses, and for decades scientists have failed. So far, it seems.

“This is a historic moment. The long-awaited malaria vaccine for children is a breakthrough for science, children’s health and the fight against malaria, ”WHO Director-General Tedros Adhanom Ghebreyesus said in a statement. declaration announcing their vaccine approval. “Using this vaccine in addition to existing tools to prevent malaria could save tens of thousands of young lives every year.”

Despite the good news, GlaxoSmithKline’s vaccine, which is currently codenamed RTS, S / AS01 but will be branded Mosquirix, is only modestly effective. In clinical trials evaluated for WHO approval, it was found to prevent about half of severe cases caused by P. falciparum malaria compared to the control group. But this level of efficacy was only observed in the first year of vaccination, and by the fourth year, protection had fallen to very low levels. With an efficacy of around 55%, the vaccine meets the bare minimum for WHO approval.

A big study this year found that a combination of the vaccine and antimalarial drugs can further reduce the risk of serious illness and death 70%, a much more attractive target for public health programs. But even as it is, a study has projected that the vaccine would prevent millions of cases and more than 20,000 deaths per year in sub-Saharan Africa if widely deployed.

Like other vaccines before it, Mosquirix may also represent the first step towards more effective vaccines in the future. There are already several other candidates in development, including one from Modern which relies on the same mRNA platform as the company’s successful covid-19 vaccine.