2009 swine flu not the same as 1976 swine flu

Q:I was in the military in 1976 when we were required to get a swine-flu vaccine. But now I hear that there is a new swine-flu vaccine. If I was vaccinated back then, am I protected from the current swine flu?

Answer: The strain of swine flu that was circulating in 1976 is different from the swine-flu virus circulatingnow, according to the U.S. Centers for Disease Controland Prevention.

Many people worry about the current vaccine because of problems with the 1976 vaccine. Federal officials said yesterday that no problems have surfaced so far in the ongoing studies of the swine-flu vaccine's safety. They emphasized that it is produced the same way seasonal vaccine is produced.

Some background: Influenza viruses circulate in humans, birds, pigs, horses and other animals. Pigs have been called flu "mixing vessels" because they can be infected with human, avian (bird) and swine-flu viruses. Those viruses can combine in pigs and create new flu strains.

The 2009 H1N1 swine-flu virus appears to be a genetic mix of swine, bird and human flu viruses, studies suggest. Because the swine-flu virus genes were identified first, it was labeled a swine flu.

Because flu viruses change, each year the seasonal flu vaccine is changed to match the virus strains health experts predict will be the main flu viruses circulating.

Some years, the vaccine is not a good match for the circulating strains and fails to protect people from getting the flu.

The new swine-flu virus was not identified in time for protection from it to be included in this year's seasonal-flu vaccine.

The Virginia Department of Health has trained people on staff to answer questions. Call toll-free (877) 275-8343 between 8:30 a.m. and 4:30 p.m. weekdays.

The department's inquiry center will be open Monday even though it's a holiday. VDH staff also will answer questions submitted by e-mail to .

Contact Tammie Smith at (804) 649-6572 or .