Both聽influenza (flu)聽and聽COVID-19聽are contagious respiratory illnesses, but they are caused by different viruses. Flu is caused by influenza viruses, while COVID-19 is caused by the SARS-CoV-2 coronavirus. Because they share many similar symptoms, it can sometimes be difficult to tell them apart without testing.
Signs & Symptoms
Flu Symptoms
- Fever or feeling feverish/chills*
- Cough
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Headache
- Fatigue (very tired)
- Vomiting or diarrhea (more common in children)
COVID-19 Symptoms
- Fever or chills*
- Cough
- Shortness of breath or difficulty breathing
- Loss of taste or smell
- Muscle or body aches
- Headache
- Fatigue
- Congestion, sore throat, or runny nose
*Not everyone with flu or COVID-19 will have a fever.
How They Spread
- Flu:聽Spreads mainly through droplets when people with flu cough, sneeze, or talk. It can also spread by touching surfaces contaminated with the virus.
- COVID-19:聽Spreads primarily through respiratory droplets and smaller particles (aerosols) when an infected person breathes, talks, coughs, or sneezes. COVID-19 is also known to spread more easily in crowded or poorly ventilated spaces compared to flu.
Contagious Period
- Flu:聽Most healthy adults can infect others from 1 day before symptoms develop and up to 5鈥�7 days after becoming sick.
- COVID-19:聽People can spread the virus 1鈥�2 days before symptoms appear and remain contagious for at least 5鈥�10 days, sometimes longer depending on illness severity.
Prevention Tips
To help prevent both flu and COVID-19:
- Maintain healthy habits聽鈥� adequate sleep, hydration, stress management, and good nutrition.
- Get vaccinated聽鈥� annual flu shots and recommended COVID-19 vaccines/boosters.
- Stay home when sick聽to avoid spreading illness to others.
- Cover coughs and sneezes聽with a tissue or the inside of your arm.
- Wash your hands often聽with soap and water, or use hand sanitizer if soap is unavailable.
- Avoid touching your eyes, nose, and mouth.
- Wear a mask聽in crowded or high-risk indoor settings, especially during outbreaks.
- Improve ventilation聽in indoor spaces when possible.