UPDATE 1-Poorer countries to get donated H1N1 vaccines - WHO

* WHO to provide donated vaccines to about 100 countries

* First deliveries for November, northern hemisphere first

* Vaccinating health workers top priority

(Adds quotes, background)

By Laura MacInnis

GENEVA, Oct 12 (Reuters) - The World Health Organisation plans to start sending H1N1 flu vaccines to poorer countries as early as next month, the United Nations agency's head of vaccine research said on Monday.

Marie-Paule Kieny said about 100 low- and middle-income nations would receive the vaccines donated by companies such as GlaxoSmithKline (GSK.L: Quote, Profile, Research) and Sanofi (SASY.PA: Quote, Profile, Research), as well as related supplies such as syringes.

"We are trying to have a first delivery starting in November," she told journalists in Geneva. "The idea is to start with northern hemisphere countries first."

The WHO declared in June [ID:nLC321991] that a full pandemic was underway from the virus widely known as swine flu. It has killed at least 4,500 people so far but caused mainly mild to moderate effects in most patients as it spread around the world.

Kieny said it was critical that health workers in poorer countries get protected against the virus to avoid passing it to the patients they treat and to ensure that hospitals and health clinics can stay open throughout an outbreak.

China began the world's first mass vaccination programme in late September, followed by Australia and the United States.

Kieny said the vaccines that have been quickly developed in response to the H1N1 strain are yielding more volume than first expected, raising hopes about the total quantity of shots that could be made available.

Work is underway to determine the exact production capacity of vaccine manufacturers worldwide, the expert said.

She signalled one dose of the vaccine could be enough to ensure protection against the flu strain, which does not appear to have morphed into a more virulent or milder form since its emergence in the United States and Mexico.

"All the data that we have seen show that one dose is sufficient," she said.

Last week, the U.N. agency said it could take years for the H1N1 infection rate to slow down. Once enough people have been exposed to the virus or have gained protection from vaccination, it could act more as a seasonal flu instead of a pandemic one, WHO spokesman Gregory Hartl said. [ID:nL9615772] (Editing by Janet Lawrence)