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Last updated July 7, 2020. 6 minute read

COVID-19 vs. the flu vs. the common cold

Coronavirus disease 2019 (COVID-19) is a respiratory disease caused by a new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was first reported in late 2019 in Wuhan, Hubei Province, China.

Dr Chimene Richa Md Written by Dr. Chimene Richa, MD
Reviewed by Dr. Tzvi Doron, DO

What is COVID-19?

Coronavirus disease 2019 (COVID-19) is a respiratory disease caused by a new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was first reported in late 2019 in Wuhan, Hubei Province, China. This illness has now spread outside of China to the rest of the world—you can click here to see the latest numbers for COVID-19 in the United States (CDC, 2020). According to the Centers for Disease Control and Prevention (CDC), SARS-CoV-2 is spread by virus-infected respiratory droplets that are produced when an infected person coughs or sneezes—these droplets can then travel up to six feet (CDC, 2020). While less likely, it is possible that the virus can spread by touching a surface that has SARS-CoV-2 on it and then touching your mouth, nose, or eyes. 

Coronaviruses belong to a family of viruses that cause different illnesses. Some cause a mild illness like the common cold while others cause more severe conditions, like Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). The new virus, SARS-CoV-2, is genetically similar to SARS but is not as deadly (WHO, 2020). COVID-19 can cause mild to severe symptoms; more than 80% of people with COVID-19 have mild disease, but about one in six people have more severe symptoms (WHO, 2020).

The signs and symptoms of COVID-19 usually appear within 14 days of the time of infection and can include fever, dry cough, tiredness, aches and pains, sore throat, diarrhea, eye inflammation, headache, loss of taste, loss of smell, discoloration of fingers or toes, difficulty breathing, shortness of breath, chest pain or pressure, and loss of speech or movement (WHO, 2020). In rare instances, the incubation period (period after infection before symptoms occur) can be over 20 days.

There is no cure and no vaccine available for COVID-19 at this time. For now, the best treatment is prevention using healthy hygiene practices, like frequent hand-washing, avoiding people who are sick, and staying home as much as possible. Current therapies focused on improving the symptoms. If the symptoms are severe, patients may require hospitalization.

Vitals

  • COVID-19 is a new illness that was first reported in Wuhan, Hubei Province, China.
  • Influenza (the flu) affects approximately 8% of the population in the U.S. each year and one billion people worldwide.
  • The common cold affects millions every year, and most adults get 2–3 colds per year; children can get more.
  • COVID-19, the flu, and the common cold are all similar in terms of common symptoms, prevention, and method of spread.
  • These viruses differ in terms of infection rates, complication rates, risk of infection, and fatality rates, among other factors.

What is the flu?

Influenza, commonly known as “the flu,” is caused by several different strains and types of human influenza viruses. The two main types of seasonal flu viruses are influenza A and influenza B. Flu season typically starts in October, peaks December through February, and then ends around April or May (CDC, 2020). Flu viruses can cause mild to severe symptoms, with death occurring in the most serious cases. The World Health Organization (WHO) estimates that about one billion people get the flu yearly worldwide (WHO, n.d.) During the 2019–2020 flu season alone, there have been as many as 56 million people suffering from the flu, with up to 62,000 deaths from the disease in the US (CDC, 2020). The CDC estimates that about 8% of the population in the U.S. catches the flu each year. 

The flu is spread from person to person by virus-infected respiratory droplets that are produced when an infected person coughs or sneezes. Less often, you could possibly get the flu by touching an object that has flu virus on it and then touching your mouth, nose, or eyes. According to the CDC, people who have the flu are the most contagious during the first 3–4 days after they start having symptoms (CDC, 2020). However, it is possible for healthy-appearing infected people who have not developed symptoms yet to pass the flu virus on to others; they may not even realize that they are sick (CDC, 2020). The signs and symptoms of the flu include fever/chills, cough, sore throat, body aches, runny/stuffy nose, and feeling tired (CDC, 2020). Flu symptoms usually begin about two days after you contract the virus (CDC, 2020).

Most people recover from the flu without any complications, but some people can develop serious illnesses, like pneumonia, ear infections, sinus infections, as well as worsening of other health problems like asthma or diabetes. In some cases, hospitalization or even death can occur (CDC, 2020). Those with the highest risk of developing serious complications from the flu include adults aged 65 and older, children younger than five years old, people with medical problems like asthma, and pregnant women. 

If you do get the flu, antiviral medications (if taken within two days of getting sick) can help improve your symptoms and lessen the time you are sick by one or two days. However, prevention is still important. The most important way to prevent yourself from getting the flu in the first place is to get the flu vaccine each year. While not a guarantee that you won’t get the flu, the flu vaccine reduces flu-related symptoms and decreases your risk of having a serious complication from the flu (CDC, 2020). Other things you can do to keep from catching the flu include frequent hand-washing, avoiding people who are sick and staying home if you develop symptoms.

What is the “common cold”?

Millions of people in the U.S. get the common cold—adults have around 2–3 colds every year, and children may have even more (CDC, 2019). It is a major cause of missed work or school. More than 200 viruses cause the common cold, including strains of coronavirus, adenovirus, respiratory syncytial virus, and enterovirus, but rhinovirus is the number one cause of the common cold (CDC, 2019). Like other respiratory illnesses, the common cold is spread through close personal contact and airborne respiratory droplets. The most common symptoms are cough, runny nose, sore throat, headaches, and body aches. While most people get better within 7–10 days, those with weak immune systems or lung conditions may develop a more serious illness, like pneumonia (CDC, 2019).  

There is no cure for the common cold, and therapies focus on improving your symptoms. Prevention involves healthy practices like frequent hand-washing, avoiding people who are sick, and staying home if you develop symptoms.

COVID-19 vs. the flu vs. the common cold: Putting it all together

There are both similarities and differences among COVID-19, the flu, and the common cold, and it can be difficult to tell them apart. These figures summarize how these three respiratory viruses compare to each other.

What do COVID-19, flu, and common cold viruses have in common?

How the virus spreads By virus-infected respiratory droplets that are produced when an infected person coughs or sneezes; may also get it by touching contaminated surfaces
Symptoms Fever, cough, runny/stuffy nose, sore throat, headaches, body aches, and feeling tired
Prevention Frequent hand washing, staying home if you have symptoms, and limiting contact with people who are sick
Treatment Mainly focuses on improving symptoms; in severe cases, may require hospitalization

How are COVID-19, flu, and common cold viruses different?

COVID-19 Flu Common cold
Cause SARS-CoV-2 virus Different types and strains of influenza virus; mainly influenza A & influenza B viruses Rhinovirus is the most common cause; also caused by strains of coronavirus, adenovirus, and enterovirus
Number of infections Continuing to increase Worldwide: up to 1 billion
US: 32–45 million
Millions of people get the common cold, with adults usually getting 2–3 colds per year
Timing of symptoms Symptoms typically appear within 14 days of exposure Symptoms can start from 1–4 days after exposure Start gradually and usually peak 3–4 days after illness starts
When contagious May be contagious before symptoms start May be contagious 1 day before symptoms start and up to 5–7 days after getting sick May be contagious for a few days before symptoms start and until all symptoms resolved
Risk of infection (in the US) Increased risk if you have recently been in close contact with someone who has COVID-19 Children 0–17 years: 3% 
Adults 18–64 years: 8.8%
Adults 65 and up: 3.9%
Adults get 2–3 colds per year (on average) and children may get more
Antiviral medication None Oseltamivir
Zanamivir
Peramivir
Baloxavir marboxil
None
Vaccines None Yes—need to get it every year None
Complication rate Varies depending on age and other risk factors Worldwide: 3–5 million serious cases
US: 410,000–740,000 hospitalizations per year due to flu

Risk of serious illness increased in adults  65 years and older, people with medical problems (asthma, diabetes, or heart disease), pregnant women, and children younger than 5
Lower risk than flu
Number of deaths Continuing to increase Worldwide: 290,000–650,000 per year
US: 24,000–62,0000 per year
Less likely than with flu

Conclusion

This year, in addition to worrying about the cold and flu, there is a new player in the game—COVID-19. It is not always easy to know if your cough and sniffles are from the cold, the flu, or COVID-19. The best thing you can do for yourself and your loved ones is to use healthy hygiene practices, like frequent hand-washing, avoiding people who are sick, and staying home if you develop symptoms. Encourage friends and family members to do the same. Talk to your healthcare provider if you have any questions or concerns about your symptoms or if your symptoms are severe.