Understanding the Difference Between RSV, Flu and COVID-19

Health experts warn of a “tripledemic” surge this winter as Americans face the threat of severe respiratory syncytial virus (RSV), influenza (flu) and COVID-19. In the last couple of years, both the flu and COVID-19 have been prominent in the United States, but with the addition of RSV’s prevalence this year, there are new risks when catching any of these illnesses. The Centers for Disease Control and Prevention’s (CDC) surveillance has shown an increase in RSV detections and RSV-associated emergency department visits and hospitalizations in multiple U.S. regions.

With several viruses circulating this winter, you may worry about every cough or sneeze and wonder what you have. Since these illnesses are all caused by viruses that affect your respiratory system, they also share some symptoms. This can make it challenging to know what you may be sick with when feeling under the weather. This article highlights the differences between RSV, flu and COVID-19 based on CDC information.


RSV is a common respiratory virus that usually causes mild, cold-like symptoms. Almost all children will have had an RSV infection by their second birthday. Most people recover in a week or two, but RSV can be serious, especially for infants and older adults. RSV tends to spread via surface droplets, especially high-touch areas.

RSV symptoms can appear within four to six days after getting infected. Common symptoms include:

  • A runny nose
  • Decreased appetite
  • Fever
  • Cough
  • Sneezing
  • Wheezing

These symptoms usually appear in stages—not all at once. Very young infants with RSV may only experience symptoms like irritability, decreased activity and breathing difficulties.


Flu activity typically peaks between December and February, although significant activity can last as late as May. Since the COVID-19 pandemic began, flu activity timing and duration have been less predictable.

Flu symptoms usually come on suddenly and vigorously and are more severe than a cold. Common symptoms include:

  • High-grade fever or chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headache
  • Fatigue

People with the flu often feel some or all of the above symptoms. Most people who get the flu will recover in a few days to less than two weeks, but some will develop a wide range of complications because of the flu. For example, sinus and ear infections are moderate complications, while pneumonia is serious.


COVID-19 spreads when an infected person breathes out droplets and tiny particles that contain the virus. These droplets and particles can be breathed in by others or land on their eyes, noses or mouth.

Symptoms can appear two to 14 days following exposure to COVID-19. Anyone can have mild to severe symptoms. Common symptoms include:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Diarrhea

This list doesn’t include all possible symptoms because symptoms may change as new COVID-19 variants emerge and can vary depending on a person’s vaccination status. As such, the CDC recommends COVID-19 vaccines for everyone 6 months and older and boosters for everyone 5 years and older.


Because there is some overlap between symptoms, it may be difficult to determine whether you have RSV, the flu or COVID-19 without being tested. For more information about these viruses, visit the CDC’s website.

If you’re not feeling well, stay home and call your doctor to explain your symptoms or take an at-home COVID-19 test, if available. A health care provider can also test to determine if you have RSV, the flu or COVID-19.

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