What are the differences and similarities between the common cold, flu, and COVID-19 (2019 novel coronavirus)?
It’s easy to confuse the symptoms of the common cold and flu with the symptoms of a COVID-19 infection.
The following article is designed to answer the following question. "What are the differences and similarities between the common cold, flu and COVID-19?" The table below summarizes the similar and different signs and symptoms of the common cold, flu, and COVID-19.
Mild if presentOftenOften
Occasional, mildCommonOccasional
CommonInfrequentInfrequent
CommonCommonOccasional
Very infrequentCommonOccasional
CommonOccasionalOccasional
CommonOccasionalInfrequent
NoOccasionalInfrequent
CommonCommonInfrequent
MildDry coughA dry cough, often severe
NoRareWith mild/moderate infection
NoIn severe infections*Common in severe infections*
*Needs oxygen or ventilatorAlthough the table covers the signs and symptoms of these three conditions, it does not clearly prioritize the similarities and differences that medical professionals mainly use to differentiate or diagnose them. Consequently, the following will summarize the main features of each disease and actual and/or proposed treatment.
COVID-19 Transmission
Many coronavirus types infect species of animals that occasionally (or rarely) are able to infect humans. MERS coronavirus is an example where the virus that usually only infected camels became able to infect humans. Wuhan coronavirus is similar as the initially infected people frequented an open-air food market that sold fish and animals, including wild animals. Medical researchers currently do not know the animal species infected, but wild animals are a suspected source. However, the rapid spread of the virus was due to person-to-person contact that has been responsible for the wide outbreak of this infection. Close contact with someone who is infected or with their secretions (for example, cough-generated droplets) or feces is how the virus spreads. Although this virus is contagious, the contagious period of time remains to be determined. Recent findings suggest it may be contagious even in the incubation period when the patient shows no symptoms.
Colds
The common cold is a viral infection of the upper respiratory system (nose, throat, sinuses, Eustachian tubes, trachea, larynx, and bronchial tubes). Rhinoviruses cause about 30%-50% of colds. However, more than 200 different viruses may cause the common cold. Colds are contagious, can spread from person to person, and have an incubation period of about 1-7 days. A cold's duration (how long it lasts) is about 7-10 days. However, depending upon the viral strain, a cold can last up to 2 weeks. Colds are a mild upper respiratory illness with a runny, stuffy nose without fever. Doctors mainly diagnose colds using clinical observation and medical history. No tests are necessary.
Flu (influenza)
Influenza (commonly termed the flu) is a viral infection of the upper respiratory and/or lower respiratory system. Influenza viruses cause the flu. These viruses usually cause more serious symptoms in the respiratory system than cold-causing viruses. The flu is contagious, can spread from person to person, and has an incubation period of about 1-4 days. The flu's duration varies from about 5 days to 2 weeks depending upon the severity of the infection. The flu can become an intense and potentially fatal illness (pneumonia) in some individuals. Hallmarks of the flu include mild to high fever, moderate to severe headache, cough, fatigue, and body aches/pains. Severe flu may have symptoms that develop rapidly and require supportive care. Doctors diagnose the flu based on clinical symptoms and by readily available lab tests.
COVID-19 (2019 novel coronavirus)
COVID-19 (also termed the Wuhan coronavirus, 2019 novel coronavirus, 2019-nCoV, and others) is a single-stranded, positive-sense RNA coronavirus. It is a new strain of coronavirus (the term corona means crown) responsible for causing a pandemic of serious respiratory problems that started in Wuhan, China. Researchers believe it originated from infected animals and jumped over to infecting people in a large open seafood/animal market. Also, it has been able to spread from person to person and is rapidly spreading worldwide. It is related to the SARS and MERS coronaviruses. It has an incubation period ranging from 2-14 days. Person-to-person spread may happen even if the infected person has no symptoms during the incubation period. Infected people may also not be aware they have the virus and may not show symptoms. The main symptoms of COVID-19 are fever (usually high), moderate to severe coughing, and shortness of breath. Other symptoms and signs may include a sore throat, diarrhea, body aches and pains, and a stuffy or runny nose. At first, it seemed to target people over 60 years old and have severe underlying health conditions like heart disease, lung disease, and diabetes, but recent data from Italy suggests that people 20-60 years of age may get the disease at about the same rate. About 80% recover without specific treatment, while about 20% may require some respiratory support (oxygen and/or ventilator support).
Treatments for COVID-19, flu, and the common cold
Colds: Doctors recommend rest, fluids, and over-the-counter (OTC) medications like ibuprofen (Advil) and acetaminophen (Tylenol). No vaccine is available for the common cold.
Flu: Early treatment with an antiviral drug like oseltamivir (Tamiflu), rest, fluids, and acetaminophen and respiratory support can help if flu symptoms become severe. Vaccines are available to reduce symptoms or prevent the flu.
COVID-19: Medical professionals recommend rest, fluids, acetaminophen, and respiratory support if COVID-19 symptoms become severe. Antiviral drug and vaccine research is very active but none are currently available.
Antibiotics are not indicated for these three viral diseases. However, they may be useful if secondary bacterial infections.