FAQ Flu

Influenza is unpredictable. While flu spreads every year, the timing, severity, and length of the season varies from one season to another.

CDC recommends a yearly flu vaccine for everyone 6 months of age and older as the first and most important step in protecting against this potentially serious disease. In addition to getting a seasonal flu vaccine, you can take everyday preventive actions like staying away from sick people and washing your hands to reduce the spread of germs. If you are sick with flu, stay home from work or school to prevent spreading the flu to others. In addition, there are prescription medications called antiviral drugs that can be used to treat flu illness.

Because the timing of the onset, peak and end of flu seasons varies from year to year and cannot be predicted, it is difficult to say when is the best time to be vaccinated for any one season. In trying to balance the need to get many people vaccinated before flu activity begins with concerns about potential waning of vaccine-induced immunity during the flu season, CDC and ACIP recommend that vaccination be offered by the end of October.

It takes about two weeks for the flu shot to become fully effective in your system.

The CDC recommends everyone six months and older receive an annual flu shot. Additionally, the CDC reports that each year, on average, 5 to 20 percent of the U.S. population gets the flu, tens of thousands are hospitalized and thousands die from flu-related illness. This costs an estimated $10.4 billion a year in direct medical expenses and an additional $16.3 billion in lost earnings annually.

• Even if you do get the flu after being vaccinated, some studies have shown that a flu vaccine can reduce the severity of your illness.
• A 2017 study showed that flu vaccination reduced deaths, intensive care unit (ICU) admissions, ICU length of stay, and overall duration of hospitalization among hospitalized flu patients.
• A 2018 study showed that among adults hospitalized with flu, vaccinated patients were 59 percent less likely to be admitted to the ICU than those who had not been vaccinated. Among adults in the ICU with flu, vaccinated patients on average spent 4 fewer days in the hospital than those who were not vaccinated.

Yes. It’s possible to get sick with flu even if you have been vaccinated (although you won’t know for sure unless you get a flu test). This is possible for the following reasons:

• You may be exposed to a flu virus shortly before getting vaccinated or during the period that it takes the body to gain protection after getting vaccinated. This exposure may result in you becoming ill with the flu before the vaccine begins to protect you. (Antibodies that provide protection develop in the body about 2 weeks after vaccination).
• You may be exposed to a flu virus that is not included in the seasonal flu vaccine. There are many different flu viruses that circulate every year. A flu vaccine is made to protect against the three or four flu viruses that research suggests will be most common.
• Flu vaccine varies in how well it works, and unfortunately, some people can become infected with a flu virus that a flu vaccine is designed to protect against, despite getting vaccinated. Protection provided by flu vaccination can vary widely, based in part on health and age factors of the person getting vaccinated. It also can vary based on the match between the vaccine viruses used to produce vaccine and circulating viruses that season. In general, a flu vaccine works best among healthy younger adults and older children. Some older people and people with certain chronic illnesses may develop less immunity after vaccination. Flu vaccination is not a perfect product, but it is the best way to protect against flu infection.

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

In addition, it’s important to remember that the flu vaccine contains three or four flu viruses (depending on the type of vaccine you receive) so that even when there is a less than ideal match or lower effectiveness against one virus, the flu vaccine may protect against the other flu viruses.

Yes! The CDC highly recommends flu immunizations for pregnant mothers. Studies have even shown flu vaccination when pregnant will help protect the baby from the virus. If you’re in your third trimester you will need to get Tetanus, Pertussis, Diphtheria (Tdap) which protects you and your newborn from Tetanus and Whooping Cough.