RSV, flu and COVID-19: How can you tell the difference? Doctor explains

ByPamela Parker KTRK logo
Tuesday, December 12, 2023
How to tell the difference between RSV, flu and COVID-19
Health workers are preparing for a possible "tripledemic" of flu, COVID-19, and RSV this winter. Here's how to tell the difference.

SAN FRANCISCO -- Health workers are preparing for a possible "tripledemic" this holiday season of influenza (flu), COVID-19 and respiratory syncytial virus (RSV). These have many of the same symptoms in common, and it is hard to tell which one you've caught.

We talked to Dr. David Hoffman, pediatric hospitalist at MarinHealth Medical Center, to share his insights on how to tell them apart and when you should and shouldn't worry.

"While it's impossible to know for sure which one of these viruses you have without testing, there are some distinctive symptoms for each virus," Dr. Hoffman said.

Here are some symptoms of each and a guide on what to do if you or a family member is falling sick.



The flu typically comes on very suddenly with an incubation period of one to four days, unlike COVID-19, which tends to have a gradual onset of symptoms. Typically, people feel more miserable with the flu than with other types of viruses, and it often comes with a sore throat, nausea, body aches, vomiting, or even diarrhea. A distinctive sign of the flu can be a very high fever -- as high as 103 or 104 Fahrenheit. Fever is just the body's way of fighting the infection and is not dangerous in and of itself.

Dr. Rochelle Walensky, the CDC director, said, "Hospitalizations for flu continue to be the highest we've seen for this time of year in a decade. If you do get sick, present yourself to your provider for early care. There are good antivirals to treat both flu and COVID-19."

The CDC is again suggesting people voluntarily wear masks indoors to reduce their chances of getting sick in the next few weeks.

It's not too late to get both vaccines - experts say you start getting protection within a week with a booster.

Distinctive characteristic

The most distinctive sign of the flu can be a very high fever in the 103 to 104 range.

Flu symptoms include:

  • Fever
  • Chills
  • Headache
  • Runny nose
  • Nausea
  • Fatigue
  • Loss of appetite
  • Sore throat



"The coronavirus has become familiar to most of us, and the signs are similar to flu and RSV. To complicate it further, some people become very ill, while others have very mild symptoms, and others show no symptoms at all. While most people develop symptoms within the first week after exposure, symptoms can occur from two up to 14 days after exposure to the virus."

Distinctive characteristic

"Unlike other viruses, COVID-19 can affect other areas of the body outside of the lungs and, in some instances, cause long-term effects," Dr Hoffman says.

COVID-19 symptoms include:

  • Cough
  • Brief fever
  • Shortness of breath
  • Abdominal pain
  • Loss of taste or smell
  • Congestion
  • Fatigue
  • Sore Throat
  • Nausea or vomiting
  • Diarrhea
  • Muscle or body aches
  • Headache



RSV is a virus that many adults would have already caught and it generally just causes cold symptoms for adults. "If you think back to that cold that you got that just wouldn't go away, you kept having congestion and perhaps a cough that lasted longer than usual, there's a decent chance that that was RSV. And again, symptoms of flu can include fever, chills, headache, runny nose, or congestion, nausea, fatigue, loss of appetite and sore throat," Dr. Hoffman said.

RSV causes a runny nose, congestion, and cough for most people. According to Dr. Hoffman, RSV has a greater likelihood of causing severe illness in very young children, especially those born premature or who have lung disease or heart disease. The most distinctive symptom that some children infected with RSV will exhibit is wheezing. Wheezing is a high-pitched sound with each exhalation.

"For most people, and even most kids, RSV doesn't cause a dangerous illness. But it does in a subset of kids. Even kids with significant illness that require hospitalization are usually going to do just fine. Maybe they'll need a little bit of oxygen, maybe they just need to be watched closely. RSV is most likely to cause significant or, you know, more concerning illness in very young children and very old adults," Dr. Hoffman said.

MORE: Everything you need to know about RSV symptoms, treatments, shots

For the first time this year, RSV vaccines are available.

For adults over age 60, there are two vaccines. For babies under 8 months old, there are two monoclonal antibody shots available, which are a bit different than a vaccine but still provide protection.

Certain babies and toddlers between 8 months and 19 months entering their second RSV season are recommended to receive an antibody shot.

There is also a maternal RSV vaccine, which is given to pregnant mothers in the third trimester between 32 weeks' and 36 week's gestation.

Distinctive symptom

The most distinctive symptom that some children infected with RSV will exhibit is wheezing, a high-pitched sound, with each exhalation.

RSV symptoms include:

  • Runny nose
  • Decreased appetite
  • Coughing
  • Sneezing
  • Fever
  • Wheezing

When to see a doctor

Dr Hoffman says to seek medical care right away if these symptoms appear:

  • Trouble breathing
  • Pain or pressure in the chest
  • New confusion
  • Inability to wake up or stay awake
  • Bluish lips or face
  • Severe abdominal pain
  • Refusing to eat and drink

When should I keep my child home?

If your child is exhibiting any symptoms of RSV, flu, or COVID-19, health experts advise you to keep your child home from school to avoid spreading the virus to other people. It doesn't matter which of the viruses is the culprit. Caution should be taken to prevent the spread.

Prevention: How to keep your child from getting sick

Prevention is the best medicine, particularly with these viruses. These suggestions are good ideas to avoid seasonal viruses:

  • Get your child vaccinated for flu, COVID-19, RSV, pneumococcus, and pertussis.
  • Wash your hands regularly or use hand sanitizer.
  • Sanitize high-contact surfaces, such as desks, tables, and doorknobs, if someone in your household is sick.
  • If your child is sick, have them stay home to avoid spreading the illness.

"Everyone's talking about RSV but we do see other viruses in the community as well, like metapneumovirus, which can cause bronchitis or significant respiratory infection, or viral pneumonia. There are thousands of viruses that we don't have tests for so we don't know exactly which virus it is, but we're definitely seeing more of many different respiratory infections," Dr Hoffman said.

He says the most important message he wants to impart to parents is you can do a lot more harm to yourself by being overly concerned.

"By being anxious and increasing stress, you therefore are making yourself more susceptible to all types of illness, chronic disease, and infection,' Dr. Hoffman says.

"That said, I do think that everyone should do whatever they can do to protect themselves from all of the respiratory illnesses and other vaccine preventable illnesses out there. He encouraged all pregnant mothers to get their pertussis vaccines during their pregnancy to 'cocoon' their unborn child, and preventing by preventing themselves from getting pertussis," he says.

Similarly, he urged kids to get the pneumococcal vaccine (whooping cough).

"Get the COVID-19 and flu vaccine for kids and adults. The flu vaccine will make you perhaps feel like you have a very mild cold but that's a lot better than getting seriously ill, or even dying from influenza. So a lot of people choose not to get the flu vaccine because they don't like that. But really the benefits are much greater than the very small risks of getting the flu vaccine or the inconvenience of getting the flu vaccine," Dr. Hoffman said.

"I don't think that it's a great idea to rush to your pediatrician's office or your primary care provider's office just to get tested, to try and figure out which one of these you have, aside from perhaps doing COVID-19 testing because most people who get RSV and flu and COVID-19 are going to do just fine. And so it's really only about dictating whether or not you need to isolate strictly and for how long," he said.

The fact is that these respiratory viruses tend to crop up with similar symptoms, such as cough, runny nose, and fever. Fortunately for most children, it doesn't matter which of these, or the thousands of other viruses causing respiratory illnesses or colds, your child has. Most children will recover from all of these viruses on their own, without receiving medical treatment and without serious complications. If your child is sick, consider testing for COVID-19 first to inform if and how long you need to isolate your child at home.