WHO released “Recommendations of the Strategic Advisory Group of Experts (SAGE) on Influenza A (H1N1) vaccines, 19 May 2009. Below is full text of a portion of the document”

“After considering the following issues:

1. the need for any recommendation to balance both risks and benefits,

2. the current uncertainty about the severity of influenza A (H1N1) illness,

3. the readiness of vaccine seed strains and reagents for large‐scale vaccine production,

4. the current status of production of seasonal vaccine for the Northern hemisphere, and the risks associated with a premature cessation of seasonal vaccine production, The Working Group considered it premature to recommend that commercial‐scale production of influenza A (H1N1) vaccine should start immediately.

http://www.who.int/csr/resources/publications/swineflu/SAGEH1N1vaccinerecommendation2009_05_19.pdf