Flu or COVID-19: Know the Differences and When It’s an Emergency

You’re going about your day, and it hits you — sniffles, headache, fatigue. You’re coming down with something but unsure what it is. Is it influenza (flu) or COVID-19? Figuring out what illness is causing your symptoms can be tricky, but knowing the differences between the two viruses is important.

What is Flu? What is COVID-19?

Flu and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses that infect the nose, throat, and lungs. There are two main types of flu viruses: types A and B. The influenza A and B viruses that routinely spread in people (human influenza viruses) are responsible for seasonal flu epidemics each year. Flu can cause mild to severe illness.

COVID-19 (coronavirus disease 2019) is a disease caused by the SARS-CoV-2 virus. It can be very contagious and can spread quickly. COVID-19 may attack more than your lungs and respiratory system. Other parts of your body may also be affected by the disease. Most people with COVID-19 have mild symptoms, but some people become severely ill. In contrast, flu comes on suddenly, while COVID-19 symptoms may start out mildly and then progress over the course of a few to several days.

People who are sick with flu often feel some or all of these symptoms:

• Cough
• Fatigue (tiredness)
• Fever or feeling feverish or chills
• Headaches
• Muscle or body aches
• Runny or stuffy nose
• Sore throat
• Vomiting and diarrhea, though this is more common in children than adults

Signs and symptoms of COVID-19 range from mild to severe illness and may appear two to 14 days after exposure to the virus.

Some possible COVID-19 symptoms include:

• Congestion or runny nose
• Cough
• Fatigue
• Fever or chills
• Headache
• Loss of taste or smell
• Muscle or body aches
• Nausea or vomiting
• Shortness of breath or difficulty breathing
• Sore throat

Who is most at risk for the flu and COVID-19?

People aged 65 years and older, young children, and those with certain health conditions are at higher risk of serious flu complications. Some people are more likely than others to get very sick if they get COVID-19. This includes older people, immunocompromised (have a weakened immune system), certain disabilities, or underlying health conditions.

How Flu and COVID-19 Spreads

Most experts believe that flu viruses spread mainly by tiny droplets made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of nearby people.

Less often, a person might get the flu by touching a surface or object with flu virus on it and then touching their own mouth, nose, or possibly their eyes.

COVID-19 spreads when an infected person breathes out droplets and very small particles that contain the virus. Other people can breathe in these droplets and particles, or these droplets and particles can land on others' eyes, nose, or mouth. In some circumstances, COVID-19 droplets may contaminate the surfaces they touch. Anyone infected with COVID-19 can spread it, even if they do not have symptoms.

Symptoms Shared by COVID-19 and Flu

Common symptoms shared by COVID-19, and the flu include:

• Change in or loss of taste or smell, although this is more frequent with COVID-19.
• Cough
• Diarrhea (more frequent in children with flu, but can occur in any age with COVID-19)
• Fatigue (tiredness
• Fever or feeling feverish/having chills
• Headache
• Muscle pain or body aches
• Runny or stuffy nose
• Shortness of breath or difficulty breathing
• Sore throat
• Vomiting

Treatment Differences

If you get sick with flu, influenza antiviral drugs may be a treatment option. Antiviral drugs work best when started early, ideally no later than two days after your flu symptoms begin. Flu antiviral drugs are prescription medicines (pills, liquid, an inhaled powder, or an intravenous solution) that fight against flu viruses in your body. Antiviral drugs are not sold over the counter. You can only get them if you have a prescription from a health care provider. Unfortunately, there is no fast-acting cure for influenza. However, antiviral drugs can reduce the duration of the illness by up to two days. These medications also lower the likelihood you’ll suffer severe illness.

Many people with COVID-19 get better with rest, fluids, and treatment for their symptoms. The medicine you can get without a prescription can help.

Over-the-counter medications that may help relieve symptoms include:

• Cough syrup or medicine
• Fever reducers
• Pain relievers, such as ibuprofen (Advil and Motrin) or acetaminophen (Tylenol)

A person at high risk of serious COVID-19 illness may be offered medicine to prevent mild illness from getting worse.

Test, Don’t Guess

You cannot tell the difference between flu and COVID-19 by the symptoms alone because they have so many similarities. Getting tested to confirm which virus you’re dealing with makes managing symptoms more effective.

You can go to urgent care to request a test for flu or COVID-19. Some nucleic acid amplification tests, including PCR tests, can differentiate between flu and COVID-19 at the same time. If one of these tests is unavailable, many testing locations provide flu and COVID-19 tests separately.

Getting treated early for flu and COVID-19 can reduce your risk of getting very sick. Testing can also reveal if someone has both flu and COVID-19 at the same time, although this is uncommon. People with flu and COVID-19 at the same time can have more severe symptoms than people with either flu or COVID-19 alone. Additionally, some people with COVID-19 may also be affected by post-COVID conditions (also known as long COVID).

When To Go to the Emergency Room

Most people can recover at home without medical treatment. However, you need to go to the emergency room if:

• You cannot stop vomiting.
• You feel dizzy or confused.
• You have persistent chest pressure or chest pain.
• You have trouble breathing.
• You improve and get worse again.
• You notice pressure or pain in the abdomen.

You should consult your doctor if you’re in a high-risk group for severe illness. High-risk groups include:

• Adults 65 years old and older
• Children 4 years old and younger
• People with diabetes, heart disease, asthma, and other chronic conditions
• Pregnant women

Get the Care You Need at UF Health Emergency & Urgent Care Center

At UF Health Emergency & Urgent Care Centers, our primary goal is to provide the residents of Northeast Florida and Southeast Georgia with exceptional service and the proper billing for the care they need. Our combined emergency room and urgent care is fully equipped to handle everything from allergies to fractures to chest pain, with on-site labs, CT, ultrasound and X-ray, all under one roof. The ER and urgent care centers are open 24 hours a day, 7 days a week. No appointment is necessary — just walk in!

Find the UF Health Emergency & Urgent Care Center in Jacksonville nearest you at https://euc.ufhealthjax.org/locations.