The World Health Organisation said Thursday that checks on many of the 30 deaths recorded following mass pandemic flu vaccinations had so far ruled out a direct link to the vaccines.

"Although some investigations are still ongoing, results of completed investigations reported to WHO have ruled out that the pandemic vaccine is a cause of death," said Marie-Paule Kieny, the WHO's director for vaccine research, she added.

The fatalities made up a minute fraction of at least 65 million doses of swine flu vaccines which have been administered, said the WHO, citing data from 16 countries.

For every 10,000 doses of vaccines administered, only one report of adverse effect had been logged.

Of every 100 reports of adverse effects, five are serious cases such as death, added Kieny.

"The reports so far confirmed that the pandemic vaccine is as safe as the seasonal flu vaccine," she said.

Vaccination programmes have been rolled out across some 40 countries, and the WHO is planning to start delivering vaccines at the end of November to poorer countries.

Kieny acknowledged that there was a "few days' delay" in delivery of these vaccines to some 95 countries, but added that they should get the drugs over the next three months.

The A(H1N1) pandemic has claimed over 6,250 lives since the virus was first uncovered in April.