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Does a fever mean the flu, COVID-19 or pneumonia?

Published: July 18, 2023

Written by: Barbara Brody

Mature man sleeping peacefully with his dog on his chest.

Almost everyone has experienced the cruddy symptoms of a fever, cough and aching body. In pre-pandemic times, the first culprit to come to mind might be the flu. But COVID-19 has entered the chat, and this condition has similar symptoms. If the cough is particularly bad, a provider might also look into a diagnosis of pneumonia, an infection of the lungs.

Anyone with these symptoms is encouraged to speak with their provider and get an immediate test for COVID-19. It’s also a good idea to read up about what might be wrong — and the treatments a provider might recommend for these different conditions.

In this article:

Symptoms of the flu

What does the flu look like?

The flu is caused by a virus (influenza) that often causes these symptoms:

  • chills
  • cough
  • fatigue
  • fever
  • muscle aches

Another possible symptom is a runny or stuffy nose. All of these symptoms are also common with COVID-19, but with the flu they tend to come on suddenly.

It’s important to talk to a medical provider if these symptoms pop up, especially if a home COVID-19 test turns out negative. The provider might diagnose as the flu based on symptoms alone or recommend a flu test, says Shannon Neale, MD, a family physician with HealthPartners Park Nicollet, in St. Louis Park, Minnesota.

Are there prescription treatments for the flu?

Some people are at higher risk for serious illness from the flu because of an underlying health condition, such as asthma, diabetes or heart disease. In those cases, a provider may decide to prescribe an antiviral medication. “Other people who may need an antiviral medication because they are at high risk for complications from influenza include pregnant women, very young children (especially under the age of 2) and people who live in nursing homes or other long-term care facilities,” says Dr. Neale.

Are there over-the-counter (OTC) flu products to try?

Most people with the flu should get plenty of rest and stay hydrated. OTC medications can also help reduce symptoms. Ibuprofen or acetaminophen can help bring down a fever and ease aches and pains. For chest congestion, an expectorant like Mucinex (guaifenesin) may help loosen things up. Always check with a health care provider before taking any OTC medications.

How long does the flu last?

Flu symptoms usually last five to seven days. Antiviral medication or a flu shot can help to speed recovery.

Need a flu shot? Find one at a MinuteClinic near you.

Symptoms of COVID-19

What does COVID-19 look like?

For the past few years, “it’s COVID-19 unless proven otherwise,” says Dr. Neale. Symptoms of COVID-19 include:

  • body aches
  • cough
  • fever
  • unusual fatigue

With COVID-19, people are also known to lose their sense of taste or smell. Not everyone with COVID-19 has this problem, but it’s uncommon with the flu. So that’s one difference between the two infections.

If COVID-19 is a possibility, the Centers for Disease Control and Prevention (CDC) currently recommends testing. If a home test is negative, it’s recommended to retest 48 hours later or schedule a visit with a doctor or MinuteClinic provider.

For products to help with at-home testing, consider a CVS Health at Home COVID-19 Test Kit, the FlowFlex COVID-19 Antigen Home Test or the BinaxNOW COVID-19 Antigen Self Test.

Are there prescription treatments for COVID-19?

Most people with COVID-19 don’t need a prescription, but oral antiviral treatment options are available to treat mild to moderate COVID-19 in people who are more likely to get very sick. This can include older adults ages 50 and over, people who are unvaccinated, those with certain medical conditions (like chronic lung or heart disease) or those who have a weakened immune system. Your health care provider might prescribe an antiviral medication to treat the infection.

Are there OTC COVID-19 products to try?

As with the flu, recovering from COVID-19 requires resting up and staying hydrated. For a fever or body aches, ibuprofen or acetaminophen can help. Mucinex (guaifenesin) or Robitussin may help with cough and congestion.

How long does COVID-19 last?

The symptoms from COVID-19 can last anywhere from a few days to several weeks, says Dr. Neale. Current guidelines recommend staying home for at least five days or until symptoms have resolved. If leaving the house on days 6 through 10, the CDC recommends the use of a mask to avoid infecting others.

Symptoms of pneumonia

What does pneumonia look like?

Pneumonia means that the air sacs in the lungs have become infected and inflamed. These sacs may fill with fluid or pus, which may lead to coughing up phlegm and difficulty breathing. A doctor may order a chest X-ray to see whether the sacs are filled with fluid instead of air.

Pneumonia can be caused by the flu, COVID-19 or many other infectious agents. Health care providers make a distinction between viral pneumonia and bacterial pneumonia. Viral pneumonia follows on from a cold or flu that persists. Bacterial pneumonia is caused by bacteria and may be accompanied by a mucus-y cough, high fever and severe chest pains. “If you have trouble breathing, get medical attention right away,” says Andrew Bryant, MD, associate professor at the University of Florida College of Medicine.

Are there prescription treatments for pneumonia?

Many people with pneumonia need antibiotics, says Dr. Bryant. (Even if an infection had a viral origin, such as COVID-19, a bacterial infection may have set in.) Providers might call for a blood test to help determine whether pneumonia is viral or bacterial, since antibiotics kill only bacteria.

Are there OTC pneumonia products to try?

It’s important to speak with a provider for guidance around OTC products. Ibuprofen or acetaminophen can help reduce a fever. Cough medicine is a little trickier, because coughing can help the body get rid of an infection and taking a cough suppressant could backfire by slowing this process down.

Vaccines for flu, COVID-19 and pneumonia

It’s important to stay up to date on vaccinations against the flu and COVID-19. For people 65 and older, it’s also important to stay current with pneumococcal pneumonia vaccinations. The pneumonia vaccine protects against Streptococcus pneumoniae bacteria, which is the most common cause of bacterial pneumonia.

Vaccines for all three of these conditions can be administered by a physician or at a local MinuteClinic.

This content is for informational purposes only and is not medical advice. Consult with your health care provider before taking any vitamins or supplements and prior to beginning or changing any health care practices.