FAQs: Frequently Asked Questions

Yes. The inactivated influenza vaccine can cause pain, redness, or tenderness at the site of injection. It can also cause muscle aches and low-grade fever, but because the vaccine viruses are completely inactivated, they cannot possibly cause influenza.

The live, weakened vaccine does have one side effect that can be quite serious. Because it is made of eggs, the vaccine contains small quantities of egg proteins. People allergic to eggs can have a severe, and rarely fatal, allergic reaction. For this reason, people who are allergic to eggs should not receive the influenza vaccine unless a physician administers it.

Yes. Pregnant women are more likely to experience complications and hospitalizations as a result of infection with influenza. We are suggesting that they speak with their physician before receiving the vaccine.

There are two influenza vaccines.

The “inactivated” influenza vaccine is made by taking influenza viruses, growing them in eggs, purifying them, and completely inactivating them with the chemical formaldehyde. This vaccine is given as a shot. The “live, weakened” influenza vaccine (FluMist) is made so that it cannot grow in the lungs. However, because the weakened viruses can grow in the lining of the nose, they induce an excellent protective immune response. FluMist is also made by growing the viruses in eggs. This vaccine is given as a nasal spray.

Both vaccines contain the three different strains of influenza viruses likely to cause disease that year.

Typical symptoms of influenza include fever, chills, muscle aches, congestion, cough, runny nose and difficulty breathing. Other viruses can cause symptoms similar to influenza. However, the influenza virus is the more common cause of severe, fatal pneumonia.

Because influenza is a virus, it can’t be successfully treated with antibiotics.

Influenza (flu) is a virus that infects the nose, throat, windpipe and lungs. The virus is highly contagious and is spread from one person to another by coughing, sneezing or talking.

The influenza vaccine is recommended for everyone 6 months of age and older. Children under 9 years of age who have never received an influenza vaccine require two doses. If a child under 9 years of age was immunized for the first time last season and only received one dose, he requires two doses this season.

The nasal version (FluMist) is only recommended for healthy people between 2 and 49 years of age and has the advantage of inducing an excellent immune response without requiring a shot.

The influenza vaccine is given every year because the strains of influenza viruses that circulate every year are different. Influenza is unique in its ability to change the proteins that reside on the surface of the virus. These changes mean that people naturally infected or immunized one year might not be protected the next year.