Influenza in Adults

Seasonal influenza (flu) is caused by viruses which infect the respiratory tract (the nose, throat and lungs). It is not the same as the common cold, which is another respiratory illness caused by a different virus. The flu season is unpredictable, but it often occurs from October to May and usually peaks between December and February.

Even healthy people can get the flu, and it can be serious.

People at high-risk for flu complications include:


A flu vaccine is the best defense against getting the flu. The CDC recommends that everyone over 6 months of age receive an annual influenza (flu) vaccine. By getting vaccinated you can help protect yourself and those around you from getting the flu.

Flu vaccination can reduce flu illnesses, doctors’ visits, and missed work and school due to flu, as well as prevent flu-related hospitalizations. The flu vaccine is designed to protect against three (trivalent) or four (quadrivalent) different flu viruses, depending on which vaccine you get. There are also a number of flu vaccine options available for adults - the regular dose flu vaccine, the nasal spray (for non-pregnant, healthy people ages 2-49 years), and the high dose flu vaccine (for people 65 years of age and older). The high dose flu vaccine contains 4 times the amount of antigen as the regular flu shot and preliminary studies suggest this may translate into greater protection against flu.

Vaccination is especially important for people 65 years and older. This age group is at greater risk of serious complications from the flu because immune defenses weaken as we get older. The CDC estimates that between 80-90% of seasonal flu-related deaths have occurred in people 65 years and older, and between 50-70% of seasonal flu-related hospitalizations have occurred among people in this age group.

Every flu season, visit your healthcare provider or pharmacist to get a flu vaccine as soon as its available in your area. Talk to them about whether you are a good candidate for the high dose flu vaccine, which is available for those 65 years and older. To find a location near you where you can get vaccinated, visit HealthMap Vaccine Finder.

Read updates on the current 2017-18 flu season.

Additional Resources