Two years after the World Health Organisation (WHO) recommended the RTS,S/AS01 vaccine to fight high Plasmodium falciparum malaria, the organisation has recommended R21/Matrix-M for the prevention of malaria in children.
The recommendation, announced on October 2, 2023, was based on advice from WHO's Strategic Advisory Group of Experts on Immunisation (SAGE) and the Malaria Policy Advisory Group (MPAG).
The organisation's director-general, Dr Tedros Ghebreyesus, also endorsed the new vaccine as safe and effective for preventing malaria after WHO's regular biannual meeting held from September 25 to September 29.
"The updated WHO malaria vaccine recommendation is informed by evidence from an ongoing R21 vaccine clinical trial and other studies," the organisation said in a statement.
The demand for the RTS,S vaccine, the first-ever approved malaria vaccine, already outpaces supply, so the emergence of R21 is expected to have high public health impact.
In WHO's own words, here are the features of the R21 malaria vaccine.
Four doses
Just like the RTS,S vaccine, the R21 malaria vaccine is also administered in a total of four doses consisting three primary doses and a fourth booster shot.
High efficacy when given just before the high transmission season
In areas where malaria transmission is largely limited to four or five months per year, the R21 vaccine was shown to reduce symptomatic cases of malaria by 75% during the 12 months following a three-dose series.
A fourth dose given a year after the third maintained efficacy.
Good efficacy when given in an age-based schedule
The vaccine showed good efficacy of 66% during the 12 months following the first three doses. A fourth dose a year after the third maintained efficacy.
High impact
Mathematical modelling estimates indicate the public health impact of the R21 vaccine is expected to be high in a wide range of malaria transmission settings, including low transmission settings.
Cost effectiveness
At prices of $2 to $4 per dose, the cost-effectiveness of the R21 vaccine would be comparable with other recommended malaria interventions and other childhood vaccines.
Safety
The R21 vaccine was shown to be safe in clinical trials. As with other new vaccines, safety monitoring will continue.
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The next steps for the R21 malaria vaccine include completing the ongoing WHO prequalification which would enable international procurement of the vaccine for broader rollout. The vaccine is expected to become available to countries mid-2024.