The vaccines are being distributed in some of the world's poorest nations

The report says there are conflicts of interest within the management of Gavi, which give pharmaceutical companies an opportunity to market their own products.

Gavi's stated aims are to increase the number of children being vaccinated in poorer parts of the world, and to fund research into new vaccines.

But the British-based charity Save the Children says it is concentrating on distributing new, expensive vaccines and doing nothing to combat the most important diseases of the developing world.

'Conflict of interests'

Gavi was set up in 1999 with a donation of $750m from the Bill and Melinda Gates Foundation.

It is a non-profit making body with close ties to the United Nations Children's Fund (Unicef) and the World Health Organisation (WHO).

But the charity's report says the presence of people from the pharmaceutical industry on Gavi's board is a clear conflict of interest, given that their companies could be making products which Gavi would buy and distribute.

In Nigeria, for example, only around a quarter of children are now vaccinated against measles, the report says, and globally 3m children die each year of diseases which established vaccines can prevent.

The charity says Gavi has a billion-dollar budget but only a five-year mandate.

Save the Children says it is concerned that at the end of that period, poor countries may have come to depend on expensive vaccines for minor diseases.

A spokesman for the Gates' Children's Vaccine Program, which works closely with Gavi, said the issues raised by Save the Children are real challenges which need to be addressed.

However, the World Health Organization and the International Federation of Pharmaceutical Manufacturers' Associations said an initiative like Gavi needs representatives from industry among its leadership.