News about swine flu virus, (H1N1) continues to be a headliner for medical media. According to health officials from the Centers for Disease Control and Prevention (CDC), H1N1 flu vaccine should be available in the coming weeks. But they recommend getting the seasonal flu vaccine as soon as it is available (probably within days of this article).

This year, the American public faces a flu vaccine campaign that is more sophisticated than ever before. The number of deaths so far from H1N1 is nowhere near that of the more common seasonal flu which, on average, kills 36,000 people in the U.S. annually.

Why all the concern?

H1N1 is a highly contagious virus which was first identified in America after two cases were reported in California in Mid-April 2009. Two months later, cases were reported in all 50 states. New infections in the majority of states have continued throughout late spring and summer, which is very unusual for North American flu viruses. Our typical winter flu season begins in December and goes through March. Health experts are concerned about the combined impact of H1N1 and seasonal flu.

Furthermore, H1N1 poses a greater risk to children and young adults, while seasonal flu is more risky for older adults. In other words, it is anticipated that many Americans may be exposed to either or both flu viruses over the winter. People with chronic medical problems (for example, asthma, diabetes, heart and kidney disease) have increased risk of severe illness from both viruses.

Finally, H1N1 is a completely new flu virus. Thankfully, it is not highly lethal. There have been 556 deaths and 8,843 hospitalizations in the U.S. so far, according to information from the CDC dated Aug. 28, 2009. But H1N1 has proven to be unpredictable and unique compared to previous flu viruses, which has led to heightened concern.

Many questions regarding the new H1N1 vaccine have emerged over the past few weeks. Here are my top five:

• Will it be necessary to get both the seasonal flu vaccine and the swine flu H1N1 vaccine? Why not just one of them?

Yes. The seasonal flu virus is different from the swine flu virus. Our immune system recognizes different surface proteins associated with these virus particles. Immunity to the seasonal flu will not give you immunity to the swine flu and vice versa.

• Can the seasonal flu shot and swine flu H1N1 vaccine be given in one injection?

At the time of this posting it is advisable to have separate injections of the two vaccinations. The seasonal flu vaccine is expected to be available before the swine flu H1N1 vaccine. Recommendations are to get vaccinated to seasonal flu as early as possible. Subsequent injection(s) will be required for the swine flu (H1N1). There may be a requirement for two injections (separated by a few weeks) for full protection against H1N1.

• What if you are allergic to egg? Can you get the H1N1 vaccine?

The new swine flu H1N1 vaccine is being prepared the same way as the seasonal flu vaccine (egg embryos are used). This means that egg-allergic people may risk having a reaction to the injection. Similar steps should be taken to avoid this risk, as with the seasonal flu vaccine. Egg allergy should be confirmed by testing. People with confirmed egg allergy should not get vaccinated unless it is administered under the guidance of a board certified allergist.