What is the flu?
Influenza (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.1
There are four types of influenza viruses: A, B, C, and D. Influenza A and B viruses commonly circulate and are responsible for seasonal epidemics.
Symptoms of influenza begin around 2 days after being infected by someone who has the virus.3
These include:
Fever
Cough
Sore throat
Runny/stuffy nose
Muscle/body ache
Headache
Fatigue
Vomiting/Diarrhea
The flu and the common cold are both respiratory illnesses, but they are caused by different viruses.
Complications from the flu can be more serious. While most people recover in a few days, some may develop complications that can be life-threatening. Serious complications triggered by flu include pneumonia, myocarditis, and may even lead to an extreme inflammatory response in the body. The flu can also worsen existing chronic medical conditions. For instance, people with asthma may experience asthma attacks while they have flu.3
How does the Flu Spread?
Flu viruses primarily spread through respiratory droplets that are released into the air when an infected individual coughs, sneezes, or speaks. These droplets can travel a short distance and may land in the mouths or noses of people who are nearby, allowing the virus to enter their bodies.
In addition to direct droplet transmission, flu infection can also occur through contact with contaminated surfaces. When a person touches a surface or object that carries the flu virus and subsequently touches their mouth, nose, or eyes, the virus can be transferred and lead to infection.4
Did you know that people with flu are most contagious during the first 3 days of their illness?5
Up to 33% of influenza transmission occurs in the workplace.5
The risk of infection among household contact can be up to 38%.6