ST. LOUIS MO (KTVI-FOX2now.com) - The Secretary of Health and Human Services urged all Americans to be vaccinated against the H1N1 flu virus. Kathleen Sebelius spoke out in St. Louis after touring one of the nation's major academic centers for the study of vaccines. Saint Louis University's Center for Vaccine Development has been running H1N1 vaccine trials since July. Sebelius pointed to evidence researchers discovered that one flu shot will develop a person's immunity to H1N1 flu within eight to ten days.

"It would have never happened with out SLU and the other seven centers that do the cutting edge clinical trials making sure we get the right dose , making sure the right virus has been identified," the Secretary said.

SLU researchers will continue collecting data from volunteers particularly those who are pregnant or very young. The center's director, Dr. Robert Belshe said he was convinced the vaccine is safe and will not cause adverse side effects. "People should not hold back . The flu is here now . We're in the midst of a large outbreak here in Missouri there's a lot of flu in St. Louis," Dr. Belshe said.

Some internet blogs have pointed to questions raised in 1976 when a vaccine against a form of "swine" or H1N1 flu was rapidly produced. Some who received the vaccinations also came down with a paralyzing disease known as Guillain Barre Syndrome. Dr. Belshe said it will take thousands of vaccinations this time to see if there is any connection. "We don't expect it," Dr. Belshe said. This year's H1N1 vaccine is being made following the same procedures manufacturers use to produce the regular seasonal flu vaccine which has not caused such problems.

By the end of the week, Missouri should have 87,000 doses of H1N1 flu vaccine on hand. Health care providers, pregnant women and young people from age six months to 25 will receive priority for the vaccinations along with adults who have underlying health problems including asthma. Missouri's Health and Senior Services director Margaret Donnelly expects local health departments to make sure those most at risk receive the innoculations first. She said health adults would be turned away until about December. But there should be enough vaccine to offer everyone in the country. The government is paying for it, however doctors and clinics may charge an administration fee.

For information on flu symptoms, treatment and the vaccinations go to flu.gov.