More than 3,000 people a day have a heart attack. If you're one of them the day after your swine flu shot, will you worry the vaccine was to blame and not the more likely culprit, all those burgers and fries?
The government is starting an unprecedented system to track possible side effects as mass flu vaccinations begin next month. The idea is to detect any rare but real problems quickly, and explain the inevitable coincidences that are sure to cause some false alarms.
"The recurring question is, 'How do we know it's safe?'" said Dr. Gregory Poland of the Mayo Clinic.
AP by Lauran Neergaard, 09/27/09