The world's first malaria vaccine is promising but should be used on a pilot basis before any wide-scale use, given its limited efficacy, World Health Organization (WHO) experts said on Friday.
The decision is likely to delay a possible broad roll-out of the shot for between three and five years.
GlaxoSmithKline's Mosquirix could, in theory, help stop millions of cases of malaria in young children in Africa at risk of the deadly mosquito-borne disease.
However, it is less effective than vaccines against many other diseases and there is uncertainty as to whether countries can effectively administer the four doses needed.
Jon Abramson, chairman of the WHO Strategic Advisory Group of Experts, or SAGE, said experts recommended there should be three to five demonstration projects in children aged five to 17 months before considering wider use.
These projects could involve up to 1 million children and would likely take three to five years to run, he added. SAGE did not recommend the use of Mosquirix, also known as RTS,S, in young babies.
Committee experts said it was vital to give all four doses of the vaccine to ensure optimal efficacy, even though getting children back for multiple repeat shots could be challenging.
"If we can't get four doses of this vaccine into the children, we're not going to be using it," Abramson told reporters.
