* The flu season may not be over for this year, and swine flu could still return in strength. At least half the population remains susceptible to the flu.
* Another possibility: The H1N1 virus could mutate and make the current vaccine, as well as next fall's version, less effective.
SHOOT: I know a LOT of people who have had flu in mid-summer in the Southern Hemisphere, so I'm not sure whether this has gone away at all.
This has been a flu season like few others.
Flu experts estimate that more than half the country's population may still be vulnerable to the H1N1 virus, either because they haven't been sick or gotten vaccinated.
The new virus doesn't appear to have completely muscled out other flu viruses, as some past pandemic viruses have.