Dangers of Flu Vaccines

The flu, or influenza, is a highly contagious viral infection of the respiratory system. Most people who contract the flu experience only mild to moderate symptoms, including a high fever, aches, a cough and a sore throat. However, the flu can also cause serious respiratory conditions. About 200,000 people are hospitalized with the flu each year, according to the U.S. Centers for Disease Control and Prevention. About 36,000 die from the flu each year. One of the best ways to prevent contracting the flu is to receive the flu vaccine at the start of flu season each year. The vaccine is available in two forms: a shot and a nasal mist.

Inactive Vaccine

• The flu vaccine that is administered as a shot is an inactive vaccine, containing viruses that have been killed. It is not possible to develop a case of the flu from receiving the vaccine. The flu shot, which is typically administered in the arm, is safe for all people ages 6 months and older.

Live Vaccine

• The nasal mist flu vaccine is called a live, attenuated influenza vaccine because it contains flu strains that are alive but weakened. Some people who receive the nasal flu vaccine experience mild flu-like symptoms, including a fever, a cough, headaches and body aches and a sore throat. The nasal flu vaccine is only approved for use in people ages two to 49 who are not pregnant and do not have certain other medical conditions.

Injection Site Side Effects

• People who receive the flu shot may develop pain, soreness, redness and swelling at the injection site. These effects are typically mild and subside within a day or two of receiving the injection.

Other Side Effects

• Other known side effects of the flu shot include hoarseness, a cough, a mild fever and mild body aches. The side effects will typically subside within a few days and can be treated with over-the-counter medications such as acetaminophen and ibuprofen if they become bothersome. Mild, flu-like symptoms are the only known side effects of the nasal flu vaccine.

Severe Reactions

• No severe problems have been identified with either flu vaccine, according to the CDC. However, as with all vaccines there is a small chance of experiencing a severe reaction. Signs of a severe reaction include unusual behavior changes and a high fever. Signs of an allergic reaction include hives, wheezing, chest tightness and swelling in the face and mouth. Allergic reactions typically develop within a few minutes to a few hours of receiving the vaccine. Any severe reactions should be reported to your doctor immediately.

Warnings

• Although at least one version of the flu vaccine is safe for the vast majority of people, not all people should receive it. For example, people who are severely allergic to eggs should not receive the flu shot because it is grown in chicken eggs and can therefore cause a severe reaction. Additionally, people who are sick should wait until they feel better before receiving the flu vaccine.