Dr. Cara Natterson answers flu shot questions from the Parents Ask community....

Is the flu shot I get at the doctor’s office the same as the flu shot I could get at a pharmacy or walk in clinic?

Yes! The flu shot is the flu shot. So whether you get it at the corner store or you go to the clinic, the components are the same. Well, almost. The one big difference may be mercury preservative (thimerosal). When a vaccine is in one large vial and a nurse (or doctor or pharmacist) sticks multiple needles attached to syringes into the bottle to draw up doses of vaccine, there is a risk of contamination. So in order to keep the vaccine sterile, three things are done. First, the top of the bottle (generally made of rubber) is swabbed with alcohol before it is punctured. Second, a new sterile needle is used each time vaccine is drawn up. And third, a preservative is used in the vaccine solution to prevent bacterial contamination. Thimerosal is one of these preservatives. If, on the other hand, vaccines are available in single-dose vials, then the amount in the vial is used in full and no preservative is needed. This is why many vaccines can be advertised as thimerosal-free: they are provided in single-dose units. Doctor’s offices and pharmacies often carry both types. When in doubt, ask.

Is Flu Mist as effective as flu shot?

Many people believe that Flu Mist is more effective than flu shot. Flu mist is a live attenuated vaccine. This means that it is made with live flu virus which has been treated so that it cannot cause overwhelming infection in the body. But it does cause a smidge of infection, which is what makes the immune system respond and “protects” a person from flu. Others disagree. In fat, a report yesterday suggests that the flu shot might actually be more effective for some people).The flu shot is not a live infection at all; in fact the virus in the flu shot is “inactivated” or down-right dead. But it still stimulates the immune system to form antibodies against flu, arming it for the upcoming winter.

There isn’t a slam-dunk answer about which one you should get. The different forms of flu vaccine are licensed for different age groups. And some folks with underlying medical conditions (like asthma or immunocompromise) are advised against the live vaccine. But most vaccine advocates believe that regardless of type—mist or shot—people are better off with some form of vaccine over no vaccine.

If my kid is allergic to eggs and can't get the shot, is there any alternative for him?

Not really. Both flu shot and Flu Mist are made with egg, so severely egg allergic individuals are advised against both. But there are many people who have mild egg allergies. For this group, there are options. Some doctors opt to have the patients pre-medicate with an antihistamine (like Benadryl) and then wait in the doctor’s office for a hour or so after the immunization is given. Other do allergy testing (using blood or scratch tests) to determine the risks associated with the vaccine for a given person. The real dilemma comes when a person is both severely egg allergic and has a history of asthma. Doctors worry about asthmatics getting influenza infection because the virus can precipitate significant wheezing episodes; but if the person is severely egg allergic, then there really isn’t an option to protect him with a flu vaccine. For more information from the experts on the flu...watch our video below.