The World Health Organization (WHO) has revised it's estimate of how much bird flu vaccine could be available were a pandemic scenario to unfold.
The WHO says recent scientific advances and increased vaccine supply means that more pandemic influenza vaccine courses will be accessible in the future.
Last year the WHO, together with vaccine manufacturers, stated that about 100 million courses of pandemic influenza vaccine based on the H5N1 avian influenza strain could be produced immediately with standard technology.
Because of a more efficient formula that figure has now been revised to 4.5 billion pandemic immunization courses per year in 2010.
WHO's Director for vaccine research, Dr. Marie-Paule Kieny, says although the revised figures demonstrate significant progress, they are still far from the 6.7 billion immunization courses that would be needed in a six month period to protect the whole world.
Dr. Kieny says drug makers such as Novartis, GlaxoSmithKline and Sanofi Pasteur are now able to produce 565 million doses of seasonal flu vaccines a year, as against 350 million in 2006.
But Dr. Kieny warns that accelerated preparedness activities backed by political impetus and financial support, must continue, in order to bridge the substantial gap which still exists between supply and demand.
According to the International Federation of Pharmaceutical Manufacturers & Associations, this year manufacturers have been able to increase the production capacity of trivalent (three viral strains) seasonal influenza vaccines to an estimated 565 million doses, from 350 million doses produced in 2006.
Experts say the yearly production capacity for seasonal influenza vaccine is expected to rise to 1 billion doses in 2010, provided corresponding demand exists.
The amount of antigen that has to be used to make each dose of the vaccine is linked to vaccine production capacity.