Countries like India and Africa - hotbeds for malaria - await the world's first vaccine against the disease.
A leading expert said the results of clinical trials were "modestly encouraging", but nations should be cautious.
For David Warrell, international director at the Royal College of Physicians (RCP), the catch lies in proper funding by charitable organisations to enable the RTS,S/AS01 vaccine being made available at reasonable rates to people in developing nations.
The vaccine is speculated to come out by 2015.
"There should be low expectations initially, unless it is taken up by these massive charities. Expectations should be low because of the cost. If wealthy billionaires in India decide they would invest money on this, they could make it happen," Warrell said here.
He was addressing reporters on the sidelines of "Medicon International 2013" organised by RCP in collaboration with Peerless Hospital and B.K.Roy Foundation, Kolkata.
RTS,S/ASO1 has been developed by British drugmakers GlaxoSmithKline Biologicals (GSK) and the PATH Malaria Vaccine Initiative (MVI) which has been funded by the Bill and Melinda Gates Foundation. It protects against the parasite Plasmodium falciparum, which causes severe malaria.
Latest results from the third set of the Phase 3 trial of the vaccine has shown promise among candidates - 15,460 infants and young children in seven sub-Saharan African countries namely Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique, and Tanzania.
The number of malaria cases in the young came down by half after 18-months follow-up, whereas in infants, incidences reduced by around a quarter.
"Now GSK seeks to licence the vaccine. It is a bit of a landmark, but not the complete solution. Instead of 10 or 20 years, we will have some sort of a vaccine in two or three years," he said.
According to WHO, Africa is the most affected continent with about 90 percent of all malaria deaths occurring there.
In Southeast Asia, the second-most affected region in the world, India has the highest malaria burden (with an estimated 24 million cases per year), followed by Indonesia and Myanmar.