In this excerpt from our Health After 50 newsletter, Johns Hopkins doctors answer frequently-asked questions about flu shots. Bottom Line Recommendation: Get your flu shot!
It's flu season once again. October and November are the best months for vaccination, but a shot in December or even later can still be beneficial. Amidst the reminders and recommendations to get a flu shot, many people remain unsure about side effects, the availability of a nasal vaccine, and whether or not a flu vaccine is needed every year. Here are answers to some common flu questions.
Q. Can I get sick from the shot?
A. It is impossible for the flu shot to give you influenza. The vaccine is made up of parts of dead influenza virus, incapable of causing illness. It works by stimulating your body’s immune system to build a defense against antigens found on the virus. Some people experience a mild fever, fatigue, and muscle aches soon after receiving the flu vaccine. This is not the flu. These symptoms show that your body’s immune system is hard at work, producing antibodies to fight the virus. These side effects (which can occur after receiving any vaccine) can be managed with over-the-counter drugs such as ibuprofen, acetaminophen, or aspirin.
Q. Do I need a shot every year?
A. Yes. There are many different types of influenza virus. Types A and B cause infection in humans. Each type has many different subclasses with different antigens. Because the influenza virus constantly mutates slightly, these different subclasses change and new ones develop, making it harder for the body to continue to recognize and fight them. Every year, health officials predict the strains of virus most likely to cause widespread illness. These are the strains contained in the vaccine for that particular year and the strains you will build immunity to after receiving your shot.
Q. Does the flu shot always prevent the flu?
A. No, not always. The effectiveness of the vaccine depends in part on your general health. Illness can compromise effectiveness. In addition, people over 50 generally mount less of an immune response to the vaccine. Thus, if you're over 50 and receive a flu shot, you remain susceptible. But if you catch the flu after a flu shot, the vaccine will provide you with some protection. Usually, a vaccinated person will have a less severe illness. And the shot prevents prolonged illness, hospitalizations, complications such as pneumonia, and deaths associated with the flu.
The take-home message is: Get your flu shot!
