Are swine flu shots safe?

As the first shipments of swine flu vaccine arrive in the U.S., our readers expressed concern about the safety of the new shots. The testing on this vaccine was faster, but no less thorough than testing on other vaccines. It went through the same set of procedures. It was done in a hurry, but health officials said they didn’t cut any corners. There is no reason to believe that the H1N1 vaccine is any more dangerous than seasonal vaccine, which is given to about 100 million people each year. There is initial testing of safety and efficacy that’s done in a few hundred people. By necessity you can’t do it in thousands and thousands of people. So far, the vaccine seems to be safe in those people. To see a rare side effect, if there is one, you’d have to immunize hundreds of thousands of people.

On the off chance that there could be a rare side effect, there are huge monitoring systems in place. They'll detect any side effects pretty quickly, especially in the military, where service members are required to get the vaccine. Since the health of the military members is followed very closely, if something were to happen, we’d see it there first. In addition, electronic medical records kept by big hospitals and health insurance groups are being monitored for any evidence of side effects.

The government is making a big effort to point out that a certain number of things happen every day to people — miscarriages, heart attacks, seizures — and just because somebody gets one of these things right after they get a flu shot does not necessarily mean it’s a result of the flu shot.