EN 
ES 
ZH 
FR 
DE 
PT 
RU 
UK 
The Flu
The flu is a contagious illness caused by influenza viruses that infect the respiratory system’s nose, throat, and lungs. There are two main types of influenza viruses: influenza A and influenza B. The flu can be detected year-round but is typically spread during the fall and winter seasons, known as the flu season.
Influenza has been known to cause global pandemics when a novel (new) influenza virus is introduced into the human population. Typically, when this happens, the virus can cause serious illness and spread easily from person to person because most of the population has little to no immunity, and vaccines most likely do not exist.
How Flu Spreads
The flu typically spreads when an infected person passes respiratory droplets to people nearby. Respiratory droplets are spread when people with the flu cough, sneeze, or talk, and the droplets enter other the mouth, nose, lungs, or possibly eyes of others. Influenza viruses, such as avian (bird) flu and swine (pig) flu, are found in animals and can sometimes spread from animals to people.
Symptoms
Common symptoms of flu infection can include fever, chills, cough, sore throat, runny nose, nasal congestion, muscle or body aches, headaches, fatigue, and GI illnesses such as nausea, vomiting, and diarrhea. The flu can cause mild to severe illness and, at times, can lead to death.
Prevention & Treatment
Getting vaccinated for the flu every year is the most effective way to prevent serious illness from the flu and reduces your chances of hospitalization and death. Vaccination may also help protect others around you who are more vulnerable to severe outcomes, such as babies, older people and people with underlying health conditions.
Daily actions such as washing your hands, avoiding touching your face, covering your coughs and sneezes and avoiding contact with ill people will help prevent contracting and spreading the flu and other respiratory illnesses.
If infected with the flu, talk to your doctor or primary healthcare provider about treatments such as antiviral drugs that may be available. Seeking care early is important because some treatments for the flu are most effective within a specific timeframe. If patients wait too long to check on symptoms, their treatment options could be limited.
Pandemic Flu
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 because the virus can change into a completely new strain quite rapidly. A novel strain that shows up quickly often means:
- Most of the global population will have little to no immunity.
- A vaccine does not exist or is not yet available to the public in a large enough amount to prevent the spread of the new influenza virus.
IDHW – Influenza Tracking
Ready – Future Pandemics Planning & Response
The United States works closely with other countries and organizations to rapidly detect and respond to outbreaks of influenza that may cause a pandemic.
FAQS
CID – 2018 study published in Clinical Infectious Diseases
The above studylooked at the percentage of the U.S. population who got sick with flu using two different methods and compared the findings. Both methods had similar findings, which suggested that on average, about 8 percent of the U.S. population gets sick from flu each season, with a range of between 3 percent and 11 percent, depending on the season.
CID – 2018 study published in Clinical Infectious Diseases
The same study found that children are most likely to get sick from flu and that people 65 and older are least likely to get sick from flu. Median incidence values (or attack rate) by age group were 9.3% for children 0-17 years, 8.8% for adults 18-64 years, and 3.9% for adults 65 years and older. This means that children younger than 18 are more than twice as likely to develop a symptomatic flu virus infection than adults 65 and older.
CDC – Flu Hospitalization Rates
Flu virus infection is very common, and the number of people infected each season can only be estimated because not everyone will seek medical care or get tested. Statistical estimations (above) are adjusted to estimate the total number of flu virus infections in the United States for a given flu season. The estimates for the number of flu virus infections are then divided by the census population to estimate how common flu virus infections are in the population (called seasonal incidence or attack rate).
CDC – Recombinant Flu Vaccine
No, a flu vaccine cannot cause flu illness. Flu vaccines that are given with a needle (flu shots) are currently made in two ways: the vaccine is made either with a) flu vaccine viruses that have been killed (inactivated) and are therefore not infectious, or b) with proteins from a flu virus (which is the case for the recombinant vaccine above). Nasal spray vaccine is made with weakened (attenuated) live flu viruses and also cannot cause flu illness. The weakened viruses are cold-adapted, which means they are designed to only reproduce at the cooler temperatures found within the nose. The viruses cannot reproduce in the lungs or other areas where warmer temperatures exist.
HHS – Community Based Testing Sites
CDC – Similarities & Differences between Flu & COVID-19
Influenza (Flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a coronavirus named SARS-CoV-2, and flu is caused by infection with influenza viruses. You cannot tell the difference between flu and COVID-19 by symptoms alone because some of the symptoms are the same. Some PCR tests can differentiate between flu and COVID-19 at the same time. If one of these tests is not available, many testing locations (above) provide flu and COVID-19 tests separately. Talk to a healthcare provider about getting tested for both flu and COVID-19 if you have symptoms.
CONTACT
Can’t find the information you need? Please complete the form or give us a call.
Communicable Diseases Control
208-327-8625
POST/UPDATES
- November 2, 2023
Mpox returns to Idaho: Health authorities stress importance of vaccination
- October 24, 2023
Health Officials Investigating Ada County Outbreak Linked to Raw Milk
- October 10, 2023
Central District Health Offering Flu Vaccinations and Updated COVID-19 Vaccine
- September 20, 2023
