“The consortia for H.I.V./AIDS vaccine development and immunology was reviewed by N.I.H. leadership, which does not support it moving forward,” said a senior official at the National Institutes of Health who was not authorized to speak on the matter and asked not to be identified.

“I think it’s objective to say to you that things will be better in the next 20 years.”

Bird flu has not been transmitted between people, but health care officials are getting ready, just in case.