Flu (Seasonal and Pandemic)

Influenza (flu) is a contagious respiratory illness that can cause mild to severe symptoms.

About flu

Seasonal flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. It can cause mild to severe illness and at times can lead to death. The best way to prevent the flu is by getting a flu vaccine each year.

Pandemic flu refers to the ability of a disease to cause a global outbreak. More specifically, an influenza pandemic is the worldwide outbreak of non-human influenza that gains the ability to infect humans often in numbers clearly in excess of normal rates.

Seasonal flu symptoms and prevention

Flu is different from a cold. Flu usually comes on suddenly. People who have flu often feel some or all of these symptoms:

  • Fever or feeling feverish/chills (though it is important to note not everyone with flu will have a fever)
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may have vomiting and diarrhea (though this is more common in children than adults)

The first and most important step in preventing flu is to get a flu vaccine each year. Flu vaccine has been shown to reduce flu related illnesses and the risk of serious flu complications that can result in hospitalization or even death. There are influenza antiviral drugs that can be used to treat flu illness.

Tracking Influenza in Idaho
2022-2023 influenza season
Elderly woman getting vaccinated
Prevent the flu - get vaccinated.
Pandemic flu

A global influenza pandemic may occur if three conditions are met:

  • A new, or novel, influenza virus is introduced into the human population;
  • The virus causes serious illness in humans, and; 
  • The virus can  spread easily from person to person.

Sometimes a disease that becomes pandemic can start in different hosts, like pigs, birds, and humans. Once the virus is capable of easily spreading from human to human, the threat of a global pandemic increases. Although a pandemic can occur with almost any disease, it is one of the more serious concerns for influenza. The concern that the influenza virus could reach pandemic levels every season is high due to the fact that the virus has the ability to change into a completely new strain quite rapidly. A novel strain that shows up quickly often means:

  • That a majority of the global population will have little to no immunity; 
  • A vaccine most likely does not exist;
  • Or a vaccine is not yet available to the public in a large enough amount to prevent the spread of the new influenza virus.

The United States works closely with other countries and organizations to rapidly detect and respond to outbreaks of influenza that may cause a pandemic.

Idaho Public Health Officials are working at the state and local level to prepare for and respond to influenza pandemics in the state.


CDC resources

Learn what's new this flu season and how the CDC recommends you protect yourself.
While seasonal influenza (flu) viruses are detected year-round in the United States, flu viruses are most common during the fall and winter.
Find out who the CDC recommends get a flu vaccine and when. A flu vaccine finder helps you locate flu clinics near you.

Idaho-specific resources

Idaho public health officials are monitoring the novel coronavirus disease (COVID-19) situation very closely.
The best way to prevent seasonal flu is to get vaccinated every year.