Ghana has become the first country in the world to approve a new malaria vaccine from Oxford University, England, a potential step forward in fighting a disease that kills hundreds of thousands of children each year.
The approval is unusual as it comes before the publication of final-stage trial data.
It is unclear when the vaccine may be rolled out in Ghana as other regulatory bodies, including the World Health Organization (WHO), are still assessing its safety and effectiveness.
The mosquito-borne disease kills more than 600,000 people each year, most of them children in Africa.
Oxford scientist Adrian Hill said Ghana's drug regulator has approved the vaccine domestically for the age group at highest risk of death from malaria - children aged 5 months to 36 months.
Oxford has a deal with Serum Institute of India to produce up to 200 million doses of the vaccine - known as R21 - annually.
This is the first time a major vaccine has been approved in an African country ahead of rich nations, Hill said. Approving a vaccine before the publication of data from final-stage trials is also rare, experts told Reuters.
"Particularly since COVID, African regulators have been taking a much more proactive stance, they've been saying...we don't want to be last in the queue," Hill said.
Vaccines have taken decades to develop given the complicated structure and lifecycle of the malaria parasite. The Oxford shot is the second in recent years to be approved for use.
Childhood vaccines in the poorest parts of Africa are typically co-funded by international organisations such as Gavi, the vaccine alliance, only after getting WHO approval.
Ghana uses Gavi funding for its vaccine campaigns, although it is moving towards buying its own shots after economic growth in recent years.
Dr Derrick Sim, Gavi's managing director of vaccine markets, said the organization was ready to provide funding for R21 if WHO backs it. He said it was crucial that the cost was kept below $3, as Serum has indicated.
"This shows how close the world is to having a second approved vaccine to fight malaria," he said.
The first malaria vaccine, Mosquirix from British drugmaker GSK was endorsed by the WHO last year after decades of work but a lack of funding and commercial potential is thwarting GSK's capacity to produce as many doses as needed, demonstrating the need for another candidate.
GSK has committed to produce up to 15 million doses of Mosquirix every year through 2028, well under the roughly 100 million doses a year of the four-dose vaccine the WHO says is needed long-term to cover around 25 million children.
Ghana, Kenya and Malawi were all involved in the pilot programme for the roll-out of Mosquirix, and have begun introducing it more widely in recent months.
Since it began in 2019, 1.2 million children across the three countries have received at least one dose of the Mosquirix vaccine.
The WHO said last month that in the areas where the vaccine has been given, all-cause child mortality has dropped by 10%, a sign of its impact.
Mid-stage data from the Oxford vaccine trial involving more than 400 young children was published in September, showing vaccine efficacy of between 70-80% at 12 months following the fourth dose.
Data from an ongoing phase III clinical trial with 4,800 children in Burkina Faso, Kenya, Mali and Tanzania is due to be published in the coming months.
Hill said the data suggested a similar performance as in the phase II trial, and has been shared with regulatory authorities over the last six months.