Another 3-5 years before malaria vaccine is unveiled

The first malaria vaccine RTS,S, will initially be rolled out on a pilot basis, given its limited efficacy, World Health Organisation aisory group has recommended.

The WHO’s Strategic Aisory Group of Experts on Immunisation (Sage) and the Malaria Policy Aisory Committee (MPAC) jointly recommended that the pilot projects help understand how best to deliver the vaccine, also known as Mosquirix.

The decision is likely to delay a possible broad roll-out of the vaccine for between three and five years. It was expected that the vaccine would be recommended for use by 2017.

“The question about how the malaria vaccine can best be delivered still needs to be answered,” said Jon Abramson, chair of Sage. “After detailed assessment of all the evidence, we recommended that this question is best addressed by having 3-5 large pilot implementation projects.”

The experts recommended that the demonstration projects be conducted on children aged five to 17 months. The projects could involve up to 1 million children and are likely to take three to five years.

Mosquirix is the first malaria vaccine. It requires four doses for a child to be fully protected. The first three are given one month apart followed by an 18-month pause before the fourth dose is given.

The vaccine is likely to cost around $5 a dose, or $20 for a four-dose course, which is four times the cost of an insecticide-treated bed net. It could be funded by the GAVI international vaccine alliance, though no decision on this has been made yet.

Sage, however, did not recommend the use of Mosquirix, also known as RTS,S, in young babies.

The GlaxoSmithKline’s Mosquirix acts against P. falciparum, the most deadly malaria parasite globally, and the most prevalent in Africa. It offers no protection against P. vivax malaria, which dominates in many countries outside of Africa.

The vaccine is being assessed as a complementary malaria control tool that could potentially be added to — but not replace — the core package of proven preventive, diagnostic and treatment measures.

However, the vaccine is less effective than other vaccines against many other diseases, and there is uncertainty as to whether countries can effectively administer the four doses needed.

Hopes for the vaccine effectiveness were dampened when trial data of phase 2 in 2011 and 2012 showed it reduced malaria episodes in babies aged six to 12 weeks by only 27 per cent, and by about 46 per cent in children aged five to 17 months.

Phase 3 trials of the RTS,S vaccine involved 16,000 children from Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique, Nigeria, and Tanzania.

The vaccine reduced malaria cases by 39 per cent in toddlers aged six to 17 months and 27 per cent in infants aged six to 12 weeks. Because the vaccine’s efficacy wanes with time, the trial tested three doses delivered one month apart, followed by a booster 18 months later.

Alternative malaria vaccines are still at least five to 10 years away from being licensed.

According to Lucas Otieno, the principal investigator at the Kenya Medical Research Institute, the vaccine’s current protection is substantial because if your child has three cases of severe malaria a year instead of six, it will change their lives.

“RTS,S is the first generation malaria vaccine and it will be improved over time. It is the starting point in fighting malaria with a vaccine. Remember that if approved, it will be the first vaccine in history against a human parasite, and given the disease burden, RTS,S would prevent millions of cases of malaria,” said Dr Otieno.

Malaria claims nearly 600,000 lives a year, mostly children in sub-Saharan Africa.