Ghana and Nigeria each approved a new malaria vaccine this month, an important step in the fight against a disease that kills more than 600,000 people a year.
At least 10 other African countries are review trial data for injection, according to the World Health Organization, so more approvals are expected in the coming weeks.
The vaccine, developed by researchers at the University of Oxford, is the second to be made publicly available. The first, an injection called Mosquirix from drugmaker GSK, has been administered through a pilot program in Kenya, Ghana and Malawi since 2019, but is still in limited supply.
The new vaccine is the first malaria vaccine approved in Nigeria, whose deaths from the disease account for 31% of the global total.
«This is good news,» said Dyann Wirth, a professor of infectious diseases at the Harvard TH Chan School of Public Health, adding: «These vaccines can save lives and hospitalizations, reduce the impact of disease on the most vulnerable young children «.
It is estimated that 619,000 people died of malaria in 2021, the latest available annual total, and 96% of those deaths occurred in Africa, according to the WHO. The disease is caused by a parasite that is transmitted to humans through mosquito bites.
Scientists have been researching potential malaria vaccines since the 1960s; Mosquirix took more than 30 years to develop and test. To prevent infection, countries with high malaria rates rely mainly on bed nets, insecticides, or antimalarial drugs for children.
Next steps for the new malaria vaccine
The Oxford vaccine consists of three doses given every four weeks, followed by a fourth dose one year later. So far the only peer reviewed data in it comes from a small trial of 450 babies up to 17 months of age in Burkina Faso. Among that group, the vaccine was found to reduce the risk of malaria by 77%.
Adrian Hill, lead developer of the vaccine and co-director of the Oxford Martin Vaccine Program, said a Ptest phase 3 of 4,800 children up to 3 years of age showed similar safety and efficacy. But those findings have not been published in a peer-reviewed journal.
The WHO is still evaluating the data on the Oxford vaccine and has not yet recommended its use. Countries that don’t have their own regulatory processes for approving vaccines often stick to WHO recommendations, Wirth said, so they can still expect that.
The WHO said it does not have a specific timetable for its decision.
«Unfortunately, we are not seeing the urgency that the WHO and every other regulator on the planet has shown with Covid,» Hill said, «which is disappointing given that there are a large number of malaria deaths in young children in Africa.»
New vaccine could reach more people faster
The WHO recommendation for Mosquirix in 2021 represented a major milestone, but manufacturing challenges have led to slow implementation.
In 2015, GSK closed the Belgium plant where the vaccine was produced and did not reopen until 2019. Last year was the first year in which the plant continuously manufactured the vaccine’s antigen, the component that stimulates the immune response.
GSK has asked a company in India, Bharat Biotech, to produce the antigen for it, but that won’t happen until 2028.
To date, 1.5 million children have received the Mosquirix vaccine, according to the WHO. In addition to the three countries already administering it, 11 others have applied to receive doses, the WHO said.
«Demand for this vaccine has been unprecedented, with 29 countries having already approached Gavi saying they would like to introduce this vaccine now,» said Dr Mary Hamel, WHO malaria vaccine team leader, at a press conference on Wednesday. (Gavi is an international vaccine alliance that partners with the WHO, governments, and nonprofit organizations.)
«Demand far exceeds the supply currently available,» Hamel added.
GSK said it expects to have around 4 million doses available by the end of this year and a total of 18 million by the end of 2025.
But WHO estimates that 80 to 100 million doses of vaccines are required annually to immunize children at risk of malaria.
The Oxford vaccine could help alleviate the shortage. The Serum Institute of India has already committed to producing 20 million doses in the next two months. (The company is manufacturing the doses «at risk,» meaning it hasn’t yet reached an agreement with a buyer.)
The Oxford shot is also cheaper, at $3 per dose compared to around $10 for the GSK shot.
How do the two malaria vaccines compare?
Like the Oxford vaccine, Mosquirix consists of four doses. The first three are given monthly, beginning when the baby is 5 months old, followed by the fourth once the baby is 15 to 18 months old.
In a large scale trialthree doses of the vaccine reduced the risk of malaria in children by 28% after four years, while four doses had a slightly higher efficacy of 36%.
Hill said the efficacy of the Oxford vaccine also declines over time, but it is «still very high» after at least 3½ years.
However, the Oxford shot may prove less effective outside of a trial setting, Wirth said, since the study in Burkina Faso largely administered vaccines before the seasonal peak in malaria transmission, which comes in July. .
“I hope that when it is released on a large scale, it will have similar efficacy to the existing recommended vaccine,” he said.
No vaccine will eliminate the need for additional measures to prevent malaria from spreading, Wirth added.
“Is it a magic bullet? Will the vaccine alleviate the need for bed nets or insecticide spraying? No, definitely not,” she said. «The vaccine won’t replace the need for medicine either, but it can be added to existing tools to have a bigger impact.»