The BBC's Tom Gibb: It may be that Fidel Castro has a product which the enemy to the north can't afford to refuse

An American subsidiary of pharmaceutical giant SmithKline Beecham has been given a government licence to study whether the vaccine can be adapted for commercial use.

"What we have been given so far is a licence by the US Treasury Department to finalise an agreement with the Finlay Institute of Cuba covering the meningitis B vaccine. We are hopeful we can sign a definitive agreement with the Cubans shortly," a SmithKline spokesman said.

The vaccine - the only one of its kind against the deadly strain of meningitis B - was developed by Cuba during a serious outbreak of the disease on the island in the 1980s. Cuban health ministry statistics say the vaccine virtually eliminated the disease.

The vaccine has since been sold in Brazil, Argentina and Colombia but US domination of the big international pharmaceutical companies has made it very difficult to commercialise elsewhere.

But the BBC's Tom Gibb in Havana says it will be very hard even for the most bitter enemies of Cuban leader Fidel Castro to prohibit the sale of a vaccine which could prevent the deaths of US children.

Medical studies

Doubt still remains over whether the vaccine can be adapted to other types of meningitis B, but receiving a US treasury licence is nevertheless a significant breakthrough in trade relations between Cuba and the US, our correspondent says.

SmithKline Beecham said the agreement would allow the firm to take the vaccine to its vaccination centre in Belgium and put it through all the necessary studies.

The Belgian laboratories are owned by a US subsidiary of the group, which means they are subject to the four-decades-old US trade embargo against Cuba.

Under the terms of the licence granted by the US, SmithKline Beecham will reportedly pay the Cubans with food and medicine but the Finlay Institute would be paid in cash once SmithKline actually started selling the vaccine.

The licence has been given largely because there have been outbreaks of meningitis B in the United States itself, similar to that which caused the epidemic in Cuba.

World Heath Organization figures show that some 500,000 people a year contract bacterial meningitis, which comes in strains A, B and C.