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Is the H1N1 Swine Flu Vaccine Safe?

H1N1 Swine Flu Vaccine Safety: Hype, Myths, and Facts

Isn't the 2009 H1N1 swine flu vaccine too new to trust?

Is the swine flu vaccine brand new? Yes and no. The 2009 H1N1 swine flu vaccine is made exactly the same way as the seasonal flu vaccine, by the same manufacturers using the same materials -- except for one shiny new piece.

What has changed is the piece of the virus the vaccine uses to prime the immune system.

Vaccine experts tell WebMD this change isn't all that new. Every couple of years or so, a new variant of a seasonal flu virus comes along. When that happens, a "new" vaccine is made using the relevant part of the variant virus.

And even though the 2009 H1N1 swine flu is a genuinely new virus, it's still closely related to seasonal flu bugs. One of the vaccines in the three-in-one seasonal flu vaccine protects against seasonal H1N1 flu, which is about 75% similar to the 2009 H1N1 swine flu -- although it offers no protection against the pandemic flu.

Last year, some 100 million people got the seasonal flu vaccine. No safety issues appeared. That's reassuring, but it's no proof that something rare and unexpected can't happen.

There's no denying that the virus particle used in the vaccine has never been used before. No scientific calculation can rule out the chance that something unexpected might happen.

But one can calculate that this chance will be small. And the chance that the vaccine will prevent serious illness and deaths is very, very large.

Why should I believe what government scientists say about swine flu?

The public health agenda is to promote healthy practices -- such as eating wholesome foods and quitting smoking -- that not everyone likes. Why? Science suggests that these policies save lives and cut health care costs.

The public health agenda also promotes vaccination against disease -- even though the rare individual is harmed by a vaccine. Why? Science suggests such a policy saves lives and cuts health care costs, as long as disease risks outweigh vaccination risks. A good example is the smallpox vaccine, which eradicated one of the scourges of mankind, even though a number of people were harmed by the vaccine.

After weighing the benefits vs. the risks, the health agencies of the U.S. government have launched the most massive vaccination campaign in history to fight the 2009 H1N1 swine flu. The CDC is using simple, direct messages -- including advertising and press conferences -- to encourage people to get the vaccine.

"In public health, you have to have campaigns and try to talk people into things," Mulligan tells WebMD. "The question about the government is a very important one. But things have changed since the old days of the Tuskegee syphilis experiment. Now we have very strict regulation of government research. People can trust and believe that this is not politicians talking, but researchers presenting evidence-based recommendations."

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