The CDC (Centers for Disease Control) recommends a yearly flu vaccine for everyone older than 6 months by the end of October.

While there are many different flu viruses, a flu vaccine protects against the viruses that research suggests will be most common. The seasonal influenza (flu) vaccine is designed to protect against the three or four influenza viruses research indicates are most likely to cause illness during the upcoming flu season. Flu viruses are constantly changing, so the vaccine composition is reviewed each year and updated as needed based on which influenza viruses are making people sick and how well the previous season’s vaccine protects against those viruses.

Flu vaccination can reduce flu illnesses, doctors’ visits, and missed work and school due to flu, as well as prevent flu-related hospitalizations. Most people who get the flu will have mild illness, will not need medical care or antiviral drugs, and will recover in less than two weeks. Some people, however, that get the flu that can lead to pneumonia, hospitalization, and sometimes death. The flu also can make chronic health problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic congestive heart failure may experience a worsening of this condition triggered by flu. People older than 65 and children younger than 5 are more likely to get serious flu-related complications.

Vaccination also is important for people who live with or care for high risk people to keep from spreading flu to them. Children younger than 6 months are at high risk of serious flu illness, but are too young to be vaccinated. People who care for infants should be vaccinated instead.

What kind of flu vaccines are available? Traditional flu vaccines (called “trivalent” vaccines) are made to protect against three flu viruses; an influenza A (H1N1) virus, an influenza A (H3N2) virus, and an influenza B virus. There are also flu vaccines made to protect against four flu viruses (called “quadrivalent” vaccines). These vaccines protect against the same viruses as the trivalent vaccine and an additional B virus. There is no preference for one vaccine over another among the recommended, approved injectable influenza vaccines. If you have questions about which vaccine is best for you, talk to your doctor or other health care professional.

Does flu vaccine work right away?

No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection. That’s why it’s better to get vaccinated early in the fall, before the flu season really gets under way.

Can the vaccine provide protection even if the vaccine is not a “good” match?

Yes, antibodies made in response to vaccination with one flu virus can sometimes provide protection against different but related viruses. A less than optimal match may result in reduced vaccine effectiveness against the virus that is different from what is in the vaccine, but it can still provide some protection against influenza illness.

In addition, even when there is a less than optimal match or lower effectiveness against one virus, it’s important to remember that the flu vaccine is designed to protect against three or four flu viruses, depending on the vaccine.

For these reasons, even during seasons when there is a less than optimal match, CDC continues to recommend flu vaccination.

Why is there sometimes not a good match between a vaccine virus and circulating viruses?

Flu viruses are constantly changing – they can change from one season to the next or they can even change within the course of one flu season. Experts must pick which viruses to include in the vaccine many months in advance in order for vaccine to be produced and delivered on time.

Can the flu vaccine give me the flu?

No. While a flu vaccine cannot give you flu illness, there are different side effects that may be associated with getting a flu shot. These side effects (soreness, low grade fever, and aches) are mild and short-lasting (two days), especially when compared to symptoms of the flu.

Where can I get a flu vaccine?

Flu vaccines are offered in many locations, including doctor’s offices, clinics, health departments and pharmacies, and even in some schools. Even if you don’t have a regular doctor, you can get a flu vaccine.

Will Miller is a PA-C at the Clover Fork Clinic.