The draft guidelines, prepared by the Food and Drug Administration, spell out the data the agency is requiring of manufacturers to demonstrate that new flu vaccines are safe and effective. The public has 90 days to comment on the guidelines before they are finalized.
Many of the guidelines reiterate FDA policies already in use, such as when the agency quickly approved last year's new flu shot Fluarix.
But others suggest that FDA is thinking critically about how to oversee some of the most novel approaches to flu-vaccine development currently being researched — such as nasal-spray vaccines containing live, but weakened, strains of bird flu.
Perhaps more importantly, the guidelines make clear that there are a variety of approaches to creating vaccines to fight the next pandemic. They allow for emergency approval if a completely new super-strain of flu suddenly appears. Or, manufacturers could systematically create and stockpile a library of vaccines against brewing new strains. They even allow for the possibility of one day vaccinating people against a potential future pandemic strain at the same time they get their regular winter flu shot.
"If that particular strain were to become the pandemic, at least we would not be naive to that strain. You could have that strategy," said Dr. Norman Baylor, head of FDA's vaccine office.
But rather than focus on any one strategy, the draft guidelines spell out different approaches to approval.
"What we really want to do is get manufacturers really ramped up, and bring on new manufacturers, so we can meet that target of making sure we have the capacity to make enough influenza vaccine ... for everyone who needs it," Baylor said.
In the case of a previously approved flu vaccine, manufacturers could tweak the vaccine for use against a new flu strain without having to seek a new license from the FDA, according to the draft documents.
Additionally, a manufacturer could receive "accelerated approval" for a new flu vaccine by performing studies showing that recipients experienced a surge in protective immune-system cells. That kind of research can be done more rapidly than the traditional tracking of whether those recipients get sick.
The FDA would, however, require follow-up studies on the new vaccines once they are in use, even in the midst of a pandemic, to be sure they work, according to the draft guidelines.
Health officials worry that bird flu, as it spreads well beyond Asia, could mutate into a strain that can be easily passed from human to human, sparking a pandemic.