What are the differences between RSV, the flu, and COVID-19?

While certain symptoms overlap, each of these respiratory viruses also has a few distinct differences.

Flu symptoms

The flu can cause mild to severe symptoms that tend to come on suddenly.

Fever is often thought of as a distinguishing flu symptom. However, not everyone who has the flu will develop a fever.

COVID-19 symptoms

Symptoms of COVID-19 usually appear 2–14 days after exposure to the virus.

No two people with COVID-19 present the same way. Some people have mild symptoms while others develop severe or even life threatening symptoms.

More severe symptoms of COVID-19 include:

• difficulty breathing
• confusion
• an inability to wake up or stay awake
• pale, gray, or blue lips, face, or skin
• persistent pain in the chest

Severe symptoms are a sign to seek immediate medical care.

RSV symptoms

RSV symptoms usually begin 4–6 days after exposure to the virus. They typically appear in stages instead of all at once.

Most people have mild RSV cases. More rarely, RSV can cause severe illness and lead to bronchiolitis or pneumonia.

Very young infants may experience RSV differently. Often, their only symptoms are breathing difficulties, decreased activity and appetite, and irritability.

RSV can be very dangerous in infants under 6 months and older adults. If a child is having difficulty breathing, not drinking enough fluids, or experiencing worsening symptoms, call a doctor.

These respiratory virus symptoms share many similarities. Seeing a doctor for testing and diagnosis is the best way to determine which type of infection a person has.

Diagnosing the flu

To diagnose the flu, a doctor will swab the inside of the nose or the back of the throat for testing. Results may be available within minutes or take several hours depending on the test used.

Diagnosing COVID-19

Several types of tests are available to diagnose COVID-19. All of the options involve a nose swab.

People can self-administer at-home tests anywhere without needing to see a doctor. However, the results may not be as accurate.

Seeing a doctor or visiting a testing site is another option. They may administer a rapid test or a COVID-19 PCR test, which often provides a more accurate result.

Diagnosing RSV

A doctor may diagnose RSV based simply on a person’s medical history, the season, and a physical exam. A doctor does not necessarily do diagnostic testing when a person with RSV has milder symptoms.

However, in some people, a doctor may perform tests, such as a mouth swab or blood test, to confirm the diagnosis.

In people with severe cases of RSV who require hospitalization, a doctor may perform additional tests, such as a chest X-ray, CT scan, or blood and urine cultures, to monitor for RSV-related complications.

Confirming an accurate diagnosis is important for determining the correct treatment approach.

Flu treatments

When it comes to the flu, prevention is the best medicine. The CDC recommends annual flu vaccines for anyone 6 months or older as the best preventative measure toward reducing the spread of the flu.

If a person does become sick with the flu, some antiviral medications may help with symptoms in people with severe flu or in people at higher risk of serious symptoms from the flu. The CDC recommends starting treatment within 2 days of noticing symptoms. However, starting treatment later may still be helpful, especially for people in high-risk groups.

Recovery time

The CDC notes that some people will recover from the flu in a few days while others may take up to 2 weeks.

Some people may develop severe complications, including pneumonia. Complications from the flu can be severe, and in some people, they may even be life threatening.

COVID-19 treatments

The CDC also recommends people get vaccinated for COVID-19 and stay on top of the booster schedule to avoid illness.

If a person does become sick with COVID-19, a doctor may prescribe antiviral medications. Doctors often prescribe these medications to people who are at risk of getting severely ill. When people take these drugs within days of symptom onset, they can help reduce the chances of severe hospitalization and death.

However, most people with COVID-19 have milder cases, and their symptoms will resolve at home without needing hospitalization or medical treatment.

To manage the symptoms and allow these people’s bodies to heal naturally, doctors may recommend strategies, including:

• taking pain medications, such as acetaminophen (Tylenol) or ibuprofen (Advil) to reduce fever and pain symptoms
• drinking plenty of water to stay hydrated
• getting plenty of rest to allow the body to fight the virus

Recovery time

The recovery time for COVID-19 can vary widely from person to person based on factors, such as severity and symptoms.

Most people with COVID-19 recover and return to normal health. However, some people can have symptoms and complications that last for weeks, months, or even years after recovery from the illness. Even people who recover from a mild case of COVID-19 may have long-lasting symptoms.

The most commonly reported long-term symptoms include:

• fatigue
• a cough
• shortness of breath
• chest pain
• joint pain
• stomach issues
• neurological issues

This is known as post-COVID conditions (PCC) or long COVID. Experts are still doing research to better understand PCC and long COVID.

RSV treatments

According to the CDC, no specific medication has yet been approved to treat an RSV infection. Similarly, no RSV vaccine has been approved yet, either.

However, researchers are working to develop an RSV vaccine to prevent illness, as well as antiviral medication to treat RSV.

There is a treatment that may help certain babies and children with an increased risk of severe RSV to protect their health. This includes premature infants and young children with certain heart and lung conditions. Doctors administer this medication as a monthly injection during RSV season.

Otherwise, the best way to treat RSV is to take steps to manage symptoms by:

• taking over-the-counter fever reducers and pain relievers
• drinking plenty of water to stay hydrated
• monitoring a child who is sick with RSV and working with a doctor on how to keep them comfortable

Recovery time

Most people’s RSV symptoms will resolve on their own. However, this process may take 1–2 weeks.

Various respiratory viruses, including the flu, COVID-19, and RSV, share common symptoms. Anyone concerned about their symptoms should contact a healthcare professional. This is especially important for anyone in high-risk groups who are experiencing signs of respiratory illness.

Receiving an accurate diagnosis can help people respond to their condition effectively and prevent related complications. Staying up to date on recommended vaccines can also help prevent illness.