For now, the Global Fund has no plans to promote the inclusion of the new malaria vaccine, “RTS,S”, into the malaria programming it supports. Although the vaccine shows promise, there are concerns about how it can be effectively administered.
The vaccine, whose trade name is Mosquirix, was developed through a partnership between GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative. It acts against Plasmodium falciparum, the deadliest malaria parasite and the most prevalent in Africa. Clinical trials in sub-Saharan Africa over a four-year period showed it to be safe and effective, reducing malaria cases in young children by up to 36%. It is the world’s first malaria vaccine.
Two World Health Organization advisory groups – the Strategic Advisory Group of Experts on Immunization and the Malaria Policy Advisory Committee – have recommended against the immediate widespread use of the vaccine. Instead, they have called for pilot implementation in 3-5 countries in sub-Saharan Africa.
In a joint statement on 23 October, the Global Fund and Gavi said that they would wait to see what the WHO itself recommends before deciding whether and how to proceed.
There are several reasons for the caution. Some of them were summarized in an article by Seth Berkley, CEO of Gavi, and Mark Dybul, Executive Director of the Global Fund, published on the Fund’s website on 29 October.
Mosquirix requires four doses, a lot for a vaccine. The clinical trials suggest that its already low efficacy is further reduced if the fourth dose is not administered, down to about 28% protection against clinical malaria and down to nearly zero in severe cases of malaria. “That is worrying,” the authors said, “because, typically, the more doses required of a vaccine the higher the dropout rate.”
Mosquirix presents challenges in terms of how reliably the vaccine can be administered. To achieve maximum effect, it should be given to children from five months, with the fourth dose given around the age of two. “This is out of sync with the typical immunization schedule for children in poorer countries, who are brought in for routine vaccination when they are six to 14 weeks old,” the authors said.
But even if high coverage can be achieved, the authors said, “there is still a danger that news of the vaccine will give people a false sense of security and lead to a reduction in the use of other malaria interventions, which would be tragic.” Insecticide treated bednets and anti-malarial medicine have already led to a 37% global decrease in malaria cases since 2000, and a 60% decline in the malaria mortality rate.
“Mosquirix is no magic bullet and at best may prove to be a useful complementary tool in reducing malaria, but only one of many already being used,” the authors concluded.
In its statement on 23 October, the Global Fund said it is continuing to work with Gavi to plan for the possible use of a malaria vaccine “if recommended by the WHO and if the Gavi and Global Fund Boards decide to support the vaccine in conjunction with other proven malaria interventions.”
If the Global Fund and Gavi decide to promote the use of the vaccine, they will likely opt to support a pilot implementation as recommended by the WHO advisory groups.