Current research points to a vaccination program that would require each human having two shots. The problem is full protection would arrive too late. Rochester researchers say protection might be stronger if the first shot is given before a pandemic begins.

    The present strategy is based on waiting for a pandemic to start to identify the mutated virus. The next step would take several months to create a new vaccine, then several more months would pass before its available to large numbers of people. Finally, most people would likely need two shots before they had full protection.

    Having to wait that long would probably mean huge numbers of people getting ill, and possibly dying.

    The Prime and Boost method would not give full protection, but would expose the body to a new type of flu. The second shot could be given soon after the start of a pandemic.

    Researchers said people would have some built-in protection while waiting for the new vaccine, enhancing their chances of survival.

    If their research is right, frontline workers, such as doctors, nurses and other staff could be given a shot well before the arrival of a pandemic. In fact, the prime shot could be given to anyone.

    Study leader, Dr. John Treanor, said this method would allow for as many people as possible to be prepared in advance.

    In this study, the scientists looked at 37 people who were given an experimental bird flu vaccine in 1998 - this vaccine was made from the first H5N1 to jump from birds to humans in 1997 in Hong Kong.

    Seven years later they each received a booster shot aimed at another H5N1 virus strain -- a strain found in Vietnam in 2004. These people were compared to people who received their first shot in 2004 targeted at the Vietnam H5N1 virus strain.

    The scientists found that those who had been vaccinated in 1998 and then again in 2004 were better protected than those who just received one shot in 1994. Over double the number of people who received two shots had an effective immune response, compared to those given just one shot.

    The team presented their findings at the annual meeting of the Infectious Diseases Society of America. Enditem

    (Agencies)