Is it safe? U.S. vaccine experts want to build trust

As I am a pregnant lady who has to take care myself carefully, I hope the vaccine can help people from the H1N1 Swine flu ... but now I am not sure....read news below.

By Maggie Fox, Health and Science Editor - Analysis

WASHINGTON (Reuters) - When advisers to the U.S. Food and Drug Administration met to discuss a new vaccine against H1N1 swine flu last week, some of the biggest critics of vaccination were not only in the room, but at the table.

Likewise for a meeting on Wednesday of advisers who decide who will be first in line to get the vaccine, which drug companies are racing to make, test and distribute all within the space of a few weeks.

Registered nurse Vicky Debold, on the board of the National Vaccine Information Center, which questions vaccine safety, is also a member of the FDA's Vaccine and Related Biological Advisory Committee. The group's founder, Barbara Loe Fisher, asked extensive questions at the meeting.

Lyn Redwood, president of SafeMinds, a group that advocates about potential links between mercury and neurological disorders, asked questions at a meeting on Wednesday of vaccine advisers to the Centers for Disease Control and Prevention.

The U.S. federal government is more ready than it has ever been for questions, criticisms and fear of vaccines -- a state of preparedness more than 30 years in the making.

"We know that there are some people who are reluctant to vaccinate and they have heard information that concerns them," Dr. Anne Schuchat of the U.S. Centers for Disease Control and Prevention told reporters late on Wednesday.

The concerns:

*Will a vaccine against a swine-like virus cause more adverse reactions than a seasonal flu vaccine?

*Will special additives called adjuvants cause reactions?

*Will the vaccines contain thimerosal, a mercury-based preservative that critics say might cause problems?

*Is it dangerous to vaccinate against both seasonal flu and the new H1N1 flu at the same time?

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H1N1 swine flu has swept around the world in weeks, infecting millions and killing more than 800 by official counts. While only a "moderate" pandemic by World Health Organization standards, it could worsen as temperatures cool in the Northern Hemisphere, making conditions better for viruses.

Five companies are making H1N1 vaccine for the U.S. market -- AstraZeneca's MedImmune unit, Australia's CSL Ltd, GlaxoSmithKline Plc, Novartis AG and Sanofi-Aventis SA.

CSL has started trials of its vaccine in people and the U.S. National Institutes of Health starts trials next month. They will compare vaccines with and without adjuvants -- ingredients that boost the immune system response to a vaccine.

Adjuvants are used in flu vaccines in Europe but not the United States and although it would be possible to get a U.S. license under Emergency Use Authorization, officials have chosen to use vaccines without it for now.

Companies such as Glaxo say they will be ready to start vaccinating people in Europe just as the first data from those trials start emerging at the end of September. Some have questioned this speed.

The FDA's Dr. Hector Izurieta said the agency had set up an exceptionally extensive network for what is known as post-marketing surveillance.

"If something happens after vaccination, the vaccine will be accused," Izurieta told last week's meeting. "There will be many, many reports of things that could be, or not, associated with vaccination."

Vaccine regulators and public health experts are painfully aware of the last swine flu vaccination campaign. In 1976, the U.S. government rushed out a mass immunization against a swine flu virus that never spread off one military base.

Several hundred cases of a rare, paralyzing neurological disease called Guillain-Barre syndrome were reported afterward and although no clear link has ever been found to the vaccine, the incident made many people mistrustful of immunizations.

More recently, fears center on thimerosal, taken out of most vaccines after activists claimed it could cause autism -- a link discredited by many scientific studies but one that some vocal activists say is still valid.

Instead of fighting the perception, Schuchat said the CDC will roll with it. "There will be thimerosal-free formulations available for those people who are interested in that sort of preparation," she said.