WEDNESDAY, Sept. 2, 2009 (HealthDay News) -- This fall, Americans will face a double challenge in getting shots for two strains of flu -- the H1N1 swine flu and the seasonal variety.
"Two different vaccines are probably going to be out there," said Dr. Christine Mhorag Hay, an assistant professor of medicine at the University of Rochester Medical Center in New York. "I think it will be confusing."
But keeping a few simple facts in mind should cut down on the confusion and help get the vaccine to everyone who needs it, experts said.
People, especially those considered at high risk -- such as pregnant women, young children and people with preexisting health conditions, such as diabetes -- may need three shots, not just one, to fully protect themselves this year.
The U.S. Centers for Disease Control and Prevention won't know until the early fall how many doses of swine flu vaccine will be most effective but, CDC spokesman Joe Quimby said, "It's believed that two doses will be required."
The good news is that the seasonal flu shot is ready and available now. "Public health folks are urging people to get the seasonal flu vaccine as soon as possible just to get it out of the way," Hay said.
Added Sharon A. Wilkerson, dean of the Texas A&M Health Science Center College of Nursing in College Station: "Regular flu is going to be hitting us by October. January-December is the usual peak time, so it's going to be early this year. People shouldn't be waiting for the swine flu vaccine to be out before they go ahead and get a regular flu shot."
Protection against the regular flu requires only one shot, except for children under 9 who have never had a shot before: They need two, Quimby said.
But the seasonal flu vaccine won't protect you against swine flu, said Dr. Gordon Dickinson, chief of infectious diseases at the University of Miami Miller School of Medicine. "It has no benefit that we can tell against what's going to probably be the real villain this year, H1N1."
For protection against swine flu, you'll need the swine flu vaccine, which is expected to be ready by mid-October and can be administered at the same time as the seasonal flu. But the two doses of swine flu vaccine will be given three to four weeks apart, according to the CDC.
Meanwhile, the priority groups are slightly different for each vaccine.
For the seasonal flu vaccine, target groups include children aged 6 months to 19 years, pregnant women, adults 50 and over, residents of nursing homes and long-term care facilities, anyone with a chronic medical condition, health-care workers and people in close proximity to high-risk individuals.
For the swine flu vaccine, federal officials have added young adults aged 19 to 24, who have been disproportionately affected by the swine flu, and have lowered older adults down the list (unless they have an underlying medical condition) because they've shown more resistance to the infection. In all, swine flu vaccine priority groups comprise about 160 million people.
"In the seasonal flu, the priority is the elderly but they're at the bottom of the ladder for H1N1, so that's a change the public will have a problem with," said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City. "People seem to have some partial immunity to the swine flu if they are born before 1957."
This doesn't mean that older people shouldn't get the swine flu shot, just that they won't be first in line, Hay said.
Hopefully, 45 million doses of the swine flu vaccine will be available by mid- to late October, enough to vaccinate about 22 million people if they each get two doses.
Thereafter, federal officials are estimating another 20 million doses will be shipped each week after that.
"At least for the first wave, we're probably only going to vaccinate prioritized people and then everybody else," Hay said.
Of course, how all this plays out depends on how many people actually take advantage of the available vaccine. "Pregnant women are very high on the list because they've had a lot of complications from the swine flu this year, but, based on historical records, only half will get vaccinated," Hay said.
To learn more about flu, visit the U.S. Centers for Disease Control and Prevention.