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

This article is up to date as of July 6, 2026, and is based on vaccine guidance provided by the U.S. Centers for Disease Control and Prevention (CDC). Individual states may adopt their own vaccine policies and recommendations based on local public health assessments and regulatory frameworks. For the most up-to-date information, consult your state or local health department or your health care provider.

For the purposes of this article, “women” refers to biological sex.

Most people are familiar with the symptom trio of body aches, cough and fever. It used to be that a fever accompanied by a nasty cough or aching body was often suspected to be the flu. But then COVID-19 joined the conversation, and people discovered that the symptoms of both look remarkably similar. To add to that, a provider may also suspect pneumonia if a person's cough is particularly bad. However, there are many different viruses that can cause body aches, cough and fever.

So, how can people tell the difference between the flu, COVID-19 and pneumonia? In addition to speaking with a health care provider and getting tested, it's good to know what factors distinguish each illness from the others.

In this article:

What to know about the flu

Flu is common, and most people experience it at some point. Globally, there are about one billion cases of the flu each year. So, it's important to know what the flu looks like when it strikes.

Symptoms of the flu

The flu is caused by the influenza virus. It can cause these symptoms:

• Chills
• Cough
• Fatigue
• Fever
• Headache
• Muscle aches
• Runny nose
• Sore throat

Many of these symptoms are also common with COVID-19. Anyone experiencing these symptoms is recommended to speak with a health care provider, who may suggest testing for the flu and COVID-19. As rapid flu tests can sometimes produce false negative results, a provider might use their clinical judgment and diagnose someone with the flu or a flu-like illness based on symptoms alone.

How to help manage the flu

Most people with the flu have mild symptoms and don't need treatment. The typical game plan for managing flu symptoms hasn't changed much over the years. In general, it's recommended to stay home, get rest, and stay hydrated.

Are there prescription treatments for the flu?

For more serious cases of the flu, or when someone has an increased risk for flu complications, there are several antiviral medications approved to treat it. They're not sold over the counter (OTC) and require a prescription from a health care provider. These medications are different from antibiotics, which fight bacterial infections. Since the flu is a virus, antibiotics aren't effective against it.

People with certain underlying health conditions are at a higher risk of developing serious complications from the flu. These conditions can include asthma, diabetes or heart disease. In these cases, a provider may decide to prescribe an antiviral medication. Sometimes other people, like pregnant women and children, may also be prescribed antiviral medication.

How long does the flu last?

People typically recover from the flu within two weeks. However, some people may develop complications like sinus or ear infections. In severe cases, pneumonia or sepsis is also possible and may be life-threatening.

How to help prevent the flu

Getting a seasonal flu shot is the best way to reduce the risk of serious illness related to the flu. People should also consider avoiding contact with those who are sick and wash their hands regularly to help avoid spreading germs. When sickness hits, people should practice good hygiene and disinfect any common areas to minimize the risk of transferring germs to other people.

Need a flu shot? They're available from late summer to early spring at CVS Pharmacy® and CVS® MinuteClinic locations.

What to know about COVID-19

COVID-19 is a respiratory virus that is easily transferred between people. Because the virus is constantly changing, different COVID-19 variants have surfaced in the past few years.

Symptoms of COVID-19

COVID-19 can present with similar symptoms to the common cold, flu or pneumonia. Symptoms of COVID-19 can include:

• Body aches
• Cough
• Fatigue
• Fever
• Headache
• Loss of taste or smell
• Runny nose

If COVID-19 is a possibility, the Centers for Disease Control and Prevention (CDC) currently recommends testing if a person has risk factors for severe illness. If an at-home test is negative, follow current CDC guidelines on retesting. Someone who receives a positive result can consider seeking treatment by scheduling a visit with a primary care provider or MinuteClinic location.

Risk factors for severe COVID-19 illness

People with factors that put them at an increased risk of developing severe illness or complications related to COVID-19 should talk to a health care provider about testing and treatment options available to them — even if symptoms are mild. Some populations that may fall into the high-risk category include:

• Older adults, especially those over the age of 75
• People who are unvaccinated or not up to date on their COVID-19 vaccines
• People with certain conditions like chronic lung disease, heart disease or a weakened immune system

Anyone who thinks they have COVID-19 and is at an increased risk of developing a severe illness should get treatment when symptoms begin. A person doesn't necessarily need to test positive in order to start treatment, so it's important to check in with a health care provider as soon as possible.

Are there prescription treatments for COVID-19?

Most people with mild COVID-19 symptoms may recover at home with or without supportive care, which may include OTC medications such as ibuprofen and acetaminophen. For people who are more likely to get very sick, oral antiviral treatment options are available. These medications are designed help stop the virus from multiplying in the body. This can help prevent severe illness or even death. For more information on antiviral medications to treat COVID-19, speak with a health care provider.

How long does COVID-19 last?

The symptoms of COVID-19 can last up to 10 days after they start, or possibly longer for some people. However, some people can experience Long COVID symptoms for months or even years. Long COVID can impact everyone differently. Possible symptoms of Long COVID can include brain fog, coughing, fatigue and shortness of breath, though more than 200 Long COVID symptoms have been identified.

How to help prevent COVID-19

People can wear masks when sick and stay away from others to help prevent spreading the COVID-19 virus. People should also stay up to date on their COVID-19 vaccines, practice good hygiene and contact a health care provider for testing or treatment when symptoms arise.

What to know about pneumonia

Pneumonia is a serious lung infection that is most often caused by bacteria or viruses. It causes the air sacs of their lungs to fill up with fluid or pus.

Symptoms of pneumonia

Possible pneumonia symptoms can include:

• Chest pain when breathing or coughing
• Chills
• Coughing, either with or without mucus
• Fever
• Low oxygen levels in the blood
• Shortness of breath

Other symptoms, like diarrhea, headache and vomiting are also possible. Older adults with pneumonia may experience sudden confusion or weakness. Babies may have rapid breathing patterns or bluish skin and lips.

What can cause pneumonia?

Pneumonia can be caused by the flu or COVID-19 viruses, or many other infectious agents. These can include bacteria, fungi, or other viruses.

Risk factors for pneumonia

It's possible for anyone to get pneumonia. However, young children under the age of two and older adults over the age of 65 are at a higher risk of developing it due to generally having underdeveloped or weakened immune systems, respectively. Other risk factors for pneumonia can include:

• Conditions that weaken the immune system, like HIV/AIDS
• Living or spending a lot of time in crowded environments, like military barracks, nursing homes or prisons
• Lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) or cystic fibrosis
• Neurological disorders that impact the ability to cough or swallow
• Regularly breathing in toxic fumes or air pollution
• Smoking cigarettes
• Using drugs or alcohol

Are there prescription treatments for pneumonia?

Many people with pneumonia are able to recover at home with help from prescription medication. However, someone with a serious illness or certain risk factors may require hospital treatment or a stay in an intensive care unit (ICU). Depending on the nature of the infection, a person may receive prescription antibiotic, antifungal or antiviral medications.

How long does pneumonia last?

The amount of time it takes to recover from pneumonia depends on the person and how severe their illness is. Some people are able to return to normal activities within a week. For others, recovery can take more than a month. The key to recovery for people with pneumonia is to get enough rest and allow the body to heal. For more information on when a person can resume their daily routines, it's best to speak with a health care provider.

How to help prevent pneumonia

Staying up to date on vaccines may help prevent some kinds of pneumonia. It's also recommended that people practice good hygiene, quit smoking, regularly wash their hands and try to keep their immune systems strong so they can fight off illness.

Do OTC medications help with flu, COVID-19 or pneumonia?

Along with drinking fluids and getting rest, OTC medications can also help support symptom relief. Ibuprofen or acetaminophen can help bring down a fever and ease aches and pains. Cough drops or throat sprays may also help with a sore throat. Before taking any OTC cough, cold and flu medications or giving them to children, it's best to first speak with a health care provider.

Children under the age of 4 should never be given OTC cough or cold medications, and someone should always talk to a health care provider before giving cough or cold medications to a child.

Vaccines for flu, COVID-19 and pneumonia

It's important to stay up to date on vaccinations against the flu and COVID-19 — because being vaccinated can lower a person's risk of being hospitalized or even dying from a respiratory illness.

It's also important for children, people 50 and over and those with certain medical risks or conditions to stay current with pneumococcal pneumonia vaccinations. People should be aware that these vaccines only provide protection against pneumonia from pneumococcal bacteria.

Respiratory syncytial virus (RSV) can also cause pneumonia, so getting the RSV vaccine will also help protect people against pneumonia.

Key takeaways

While the flu, COVID-19 and pneumonia share many of the same symptoms, it's important for people to understand what makes them different. Both the flu and COVID-19 are viral in nature. Pneumonia is a lung infection that can be caused by bacteria, fungi or viruses. The difference is that pneumonia can be a secondary complication of many illnesses, including both flu and COVID-19. All three illnesses can have similar symptoms, including coughing and a fever.

Depending on how sick a person is, they may get over the flu, COVID-19 or pneumonia within two weeks or less, but recovery from severe cases may take longer. These infections may also result in a hospital stay if they are severe enough. All three conditions can be treated with prescription medications, but symptoms can also be managed with a variety of OTC medications when directed by a health care provider. To prevent flu, COVID-19 and pneumonia, it's recommended to stay up to date on recommended vaccines to reduce the chance of getting sick. When symptoms arise, people should make sure to speak with a health care provider, because early testing and treatment can often make all the difference in their recovery.