Swine Flu Vaccine

Anthony Komaroff, M.D., is professor of medicine and editor-in-chief of Harvard Health Publications at Harvard Medical School. Dr. Komaroff also is senior physician and was formerly director of the Division of General Medicine at Brigham and Women's Hospital. Dr. Komaroff has served on various advisory committees to the federal government, and is an elected Fellow of the American Association for the Advancement of Science.

Question:
I know there have been previous outbreaks of swine flu. Was there ever a swine flu vaccine?
Answer:
Yes. There was a swine flu vaccine about 30 years ago. There may be another released later this year. Here's what you need to know.

The " flu" is caused by influenza viruses. Flu typically occurs during late fall, winter and early spring because flu viruses like cold, dry air.

About 30 years ago, there was an outbreak of flu at Fort Dix, New Jersey, caused by a swine flu virus. This virus had previously infected just pigs, but it developed the ability to infect humans. The government thought that the virus was likely to spread widely, so they developed a swine flu vaccine. Forty million people in the U.S. got the vaccine.

To everyone's surprise, the virus did not spread widely. The reasons are still not understood. Lots of people were vaccinated, but we know now that they didn't really need the treatment.

The current outbreak of swine flu is caused by a different virus (called H1N1) than the swine flu of 30 years ago. Today's swine flu has already spread around the world much more widely than the previous virus. It is still spreading in the northern hemisphere (like here in the U.S.), even though it is nearly summer. This is very different from what happened with the swine flu outbreak in New Jersey 30 years ago.

Many experts think the current virus will cause a new wave of infections in the northern hemisphere as we approach winter, and that the illness will be more severe. For this reason, many experts agree that the world should prepare to immunize people against the new swine flu virus. The World Health Organization, the U.S. Government, and other governments are beginning the process to create a vaccine. A vaccine could be ready by September or October, although it will probably take more time to make enough vaccine to cover large numbers of people.

Deciding whether to immunize large numbers of people will be hard. That's because by the time a decision has to be made, it may not yet be clear how serious the new virus will turn out to be.

It almost surely will not be possible to know if the vaccine against the new swine flu virus will, like the vaccine 30 years ago, cause rare but serious side effects. No leader wants to have to make a decision based on incomplete evidence, but unfortunately, that is likely to be the case.