Here are some basic guidelines for telling the difference between cold, flu and COVID-19 symptoms, and what to do.

The common cold is an upper respiratory infection caused by a virus. According to the American Lung Association, more than 200 different viruses can cause the common cold. However, according to the Mayo Clinic, the rhinovirus is most often the one that makes people sneeze and sniffle. It’s highly contagious.

Though you can catch a cold at any time of year, colds are more common during the winter months. This is because most cold-causing viruses thrive in low humidity.

Colds spread when someone who’s sick sneezes or coughs, sending virus-filled droplets flying through the air.

You can get sick if you touch a surface (such as a countertop or doorknob) that has recently been handled by an infected person and then touch your nose, mouth, or eyes. You’re most contagious in the first two to four days after you’re exposed to the cold virus.

Symptoms can include:

Colds come on gradually over a few days and are often milder than the flu. They usually get better in 7 to 10 days, although symptoms can last for up to 2 weeks.

Treatment:

Because a cold is a viral infection, antibiotics are not effective at treating it.

However, over-the-counter medications, such as antihistamines, decongestants, acetaminophen, and NSAIDs, can relieve congestion, aches, and other cold symptoms. Drink plenty of fluids to avoid dehydration.

Some people take natural remedies, such as zinc, vitamin C, or echinacea, to prevent or relieve cold symptoms. The evidence is mixed on whether they work.

A 2015 study in BMC Family Practice found that high-dose (80 milligram) zinc lozenges could shorten the length of colds if taken within 24 hours of showing symptoms.

Vitamin C doesn’t seem to prevent colds, but if you take it consistently, it might lessen your symptoms, according to a 2013 Cochrane review. Echinacea hasn’t been shown to help prevent or treat colds. A 2017 study in BMJ found vitamin D helps protect against both colds and flu.

Colds usually clear up within 7 to 10 days. See a doctor if:

You could have allergies or a bacterial infection that requires antibiotics, such as sinusitis or strep throat. A nagging cough could also be a sign of asthma or bronchitis.

Influenza — or the flu, as it’s better known — is another upper respiratory illness. Unlike a cold, which can hit at any time of year, the flu is generally seasonal. Flu season usually runs from autumn to spring, peaking during the winter months.

During flu season, you can catch the flu in the same way you’d pick up a cold: By coming into contact with droplets spread by an infected person. You’re contagious starting one day before you get sick and up to 5 to 7 days after you show symptoms.

The seasonal flu is caused by the influenza A, B, and C viruses, with influenza A and B being the most common types. Active strains of influenza virus vary from year to year. That’s why a new flu vaccine is developed each year.

Unlike the common cold, the flu can develop into a more serious condition, such as pneumonia. This is especially true for:

Symptoms can include:

Flu symptoms come on quickly and can be severe. They usually last 1 to 2 weeks.

Use your symptoms as a guide to figure out which condition you have. If you think you might have the flu, see your doctor to get tested within the first 48 hours of showing symptoms.

Treatment:

In most cases, fluids and rest are the best ways to treat the flu. Drink plenty of fluids to prevent dehydration. Over-the-counter decongestants and pain relievers, such as ibuprofen and acetaminophen, may control your symptoms and help you feel better.

However, never give aspirin to children. It can increase the risk of a rare but serious condition called Reye’s syndrome.

Your doctor may prescribe antiviral medication to treat the flu.

These drugs can shorten the duration of the flu and prevent complications such as pneumonia. However, they may not be effective if not started within 48 hours of getting sick.

If you’re at risk of complications from the flu, call your doctor when you first have symptoms. People at risk of serious complications include:

Contact your doctor right away if your symptoms do not improve or if they become severe. See your doctor if you have signs of pneumonia, including:

Call a doctor right away if your child develops the following symptoms:

You may carry the virus for 2 days or up to 2 weeks before you develop symptoms.

Some common symptoms can include:

Less common symptoms can include:

However, individuals with COVID-19 may have some, all, or none of the above symptoms.

Call emergency medical services if you have or someone you care for has any of the following symptoms:

Head to a testing facility or talk with your doctor or right away if you think you have COVID-19 or you notice symptoms. Your doctor will advise you on whether you should:

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All content in Sonder's Help Centre is created and published for informational purposes only. It is not intended to be a substitute for professional advice. Always seek the guidance of a qualified health professional.

Information on cold, flu and COVID-19 gathered from Healthline.com

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