Q: What is the difference between the seasonal flu vaccine and the swine flu vaccine?
A: Each year, experts review the viruses that caused flu that season and they select three of those viruses to create the following year’s flu shot. The 2009 seasonal flu vaccine does not include swine flu virus. The swine flu vaccine contains only a single virus: the 2009 H1N1 virus. The CDC recommends that most people receive both the seasonal flu and the 2009 H1N1 vaccines. This year’s seasonal flu vaccine is expected to be protective against less than 1% of flu cases since over 99% of flu currently is due to the 2009 H1N1 virus.
Q: What’s known about the risks of flu shots?
A: Risks are considered by most experts to be very low and limited largely to local pain and swelling at the site of injection with rare instances (1 in 1 million) of a paralyzing condition known as Guillian-Barre Syndrome (that rate was higher during the previous swine flu outbreak in 1976 when the incidence was estimated at 1 in 100,000). According to the CDC, none of the shots approved for use in the U.S. will contain adjuvants (substances that enhance immune reactions) such as squalene. Vaccines containing adjuvants have been approved in Europe. However, injected flu vaccines may contain thimerosal, a mercury-containing preservative, which many doctors believe is safe but others believe may be responsible for effects on the brain and nervous system. For people who want to take the vaccine but avoid the mercury, they can ask for single-dose vaccines.
Q: I’m confused. We’re told not to rush to the doctor or hospital if we have symptoms of flu because we might spread infection, and at the same time we’re told that if we need antiviral drugs for flu that we have to be seen at the onset of symptoms in order to be effectively treated. What should I do if I have flu symptoms?
A: The best thing to do is to call your primary care doctor for advice rather than going to an emergency department since much depends on your personal risk factors. If you have any unusual symptoms, such as shortness of breath, wheezing, or difficulty taking fluids, you should seek immediate help.
Q: How dangerous is swine flu?
A: At this point, it is proving to be relatively mild and less fatal than the average flu, according to data from some countries in the Southern Hemisphere that already experienced their winter flu season. Unless the virus mutates, it appears that the most serious threat is largely to people with underlying health problems.
Q: I see studies that say the flu vaccine is highly effective. Why is there any question?
A: Effectiveness is often measured by showing that people who get the vaccine develop antibodies in response to the vaccine. Those antibodies can be helpful in fighting off future bouts of that year’s flu. The problem is that young, healthy people are very good at developing antibodies but they are not the people who tend to develop pneumonia or die, while older people and people with immune disorders, who are most likely to die, don’t develop protective antibodies as well. This has led to the question, “Is it necessary for those whom it helps, and will it help those for whom it’s necessary?”