The Cold vs The Flu: Reading the Clues
According to the Centers for Disease Control and Prevention (CDC), the 2019-2020 flu season affected between 39,000,000 and 56,000,000 Americans. (10) In Canada, 48,818 Canadians were diagnosed with the flu during the 2018-2019 season.
(17) With illness being so prevalent, understanding the differences between the common cold and the flu is necessary for determining the best remedies and treatments for a speedy recovery.
What is the common cold?
The common cold is an illness caused by one of over 200 different types of cold viruses, typically affecting the nose and occasionally the sinuses, ears, and airways. The most common virus to cause common cold symptoms is usually referred to as the rhinovirus. (8)
The incubation period, the time from infection to symptom presentation, typically occurs within 24 to 72 hours, as the body recognizes and begins to fight the infection. (16) Symptoms of the common cold often include a sore throat, sneezing, and a stuffy nose.
(13) These symptoms typically peak within a few days after infection and last for about a week; however, some individuals may experience symptoms for up to three weeks. (13)
(15) Common cold symptoms occur when your immune system, the body’s main defense system, sends out white blood cells that release inflammatory mediators. The mediators prompt an increase in mucus secretion and induce sneezing reflexes as a method to remove the virus. (11)
What is the flu?
The flu is the common name for a respiratory infection caused by an influenza virus that infects to your nose, throat, and lungs. The average incubation period ranges between one and four days, with flu symptoms manifesting after two days on average.(5)
The onset of flu symptoms occurs quickly and typically begins with a high fever (above 100°F or 38°C), body aches, and significant fatigue or weakness. (14) Though many individuals recover on their own, medical intervention may be required in severe cases in order to prevent complications. (14)
The virus that causes the flu is transmitted from one person to another through moisture, typically droplets that are spread when someone who is ill sneezes or coughs.
The droplets can transfer via direct contact, but can also be contracted by touching an object, such as a telephone or doorknob, that has been in contact with a sick person. (14)
What makes prevention difficult is that, due to the incubation period, people are often contagious before they show symptoms of illness.
Therefore, hygiene practices, such as hand-washing and avoiding touching your face, are very important to reduce the transfer of germs during cold and flu season, or when you think you might be ill. (5)
Flu vs. cold: the common symptoms
The common cold and the flu share several common signs and symptoms, making it difficult to distinguish between the two illnesses.
Below is a list of the common symptoms you will see with each illness, so you have a better idea of whether you might have a cold or a flu. Determining whether you are sick with the common cold or flu can help you and your healthcare practitioner determine the best course of action for treatment.
Learn how to identify the symptoms of the common cold and flu. (1)(2)(3)(4)(5)(6)(7)
Cold and flu prevention
The CDC recommends the following preventative measures to mitigate your risk of contracting the cold or flu, and to prevent the spread if you’re already sick:
- Avoid close contact with others if you or people around you are ill
- Avoid touching your face
- Cover your mouth and nose when coughing or sneezing
- Disinfect shared surfaces (e.g., desks, phones, door knobs, light switches)
- Stay home if you’re sick
- Wash your hands regularly with soap and water (9)
Furthemore, taking care of your body year-round can help prevent seasonal illnesses. Lifestyle habits that can reduce your risk of getting sick include:
- Eating a healthy diet and limiting consumption of processed foods
- Exercising regularly
- Getting enough sleep
- Managing your stress levels (9)
Debunking myths about the cold and flu
Most medical advice suggests rest and at-home remedies for both cold and flu illnesses, however, there are several common myths about the cold and flu that are misleading or false.
Myth: Feed a cold, starve a fever
Evidence to support restricting caloric intake when experiencing a fever is sparse. Some animal studies have indicated that limiting caloric intake may be beneficial in the treatment of bacterial infections, but not viral infections. (19)(20)
The high temperature you experience with a fever is an important defense mechanism of your immune system to fight off infection. (18)
For a fever to exist, your body increases your metabolism, which requires energy in the form of calories from food and beverages. (3) It’s essential to stay nourished and well-hydrated if you are suffering from a cold or experiencing a fever.
When you’re ill, it’s not uncommon for you to lose your appetite. Try to eat small meals and bland foods to prevent gastrointestinal upset. Be sure to also consume plenty of water and clear liquids, such as broth and electrolyte drinks, to prevent dehydration. (4)
Myth: You need antibiotics to cure the cold or flu
Both the cold and flu are viral infections. Since antibiotics are used specifically for killing bacteria, they have no effect on illnesses caused by a virus. (2)
In fact, taking antibiotics unnecessarily can lead to possible adverse health outcomes. Antibiotics have been shown to disrupt the composition and function of gut bacteria, a condition known as dysbiosis. (12)
Furthermore, antibiotic use can result in antibiotic-resistant bacterial strains that are very difficult to treat and can even become incurable. (1)
Myth: The flu vaccine can give you the flu
The flu vaccine contains inactivated (killed) versions of a virus, and therefore, cannot infect your body. (7) The flu vaccine typically includes three or four influenza virus strains, which are updated annually based on World Health Organization (WHO) recommendations.
Over 100 WHO-recognized National Influenza Centers around the world conduct extensive research and surveillance of viral activity to predict the flu strains most likely to spread in the upcoming flu season. (6) Though you cannot contract the flu from the vaccine, side effects from the vaccine may be similar to those of the flu, such as soreness and swelling at the site of injection, nausea, headache, and fever, but these typically subside within a day or two. (7)
The bottom line
Preventative practices, such as washing your hands frequently, avoiding touching your face, and disinfecting shared surfaces, can help reduce your risk of contracting the cold or flu this season. The common cold and flu have similar symptoms that can vary in severity and duration.
For either case, getting plenty of rest, staying hydrated, and eating well can help support optimal immune function. If you suspect you have the cold or flu, speak with your integrative healthcare practitioner to determine the most appropriate treatment plan for you.
- Alsan, M., Morden, N. E., Gottlieb, J. D., Zhou, W., & Skinner, J. (2015). Antibiotic use in cold and flu season and prescribing quality. Medical Care, 53(12), 1066–1071.
- Antibiotics. (1999). Paediatrics & Child Health, 4(7), 504.
- Baracos, V. E., Whitmore, W. T., & Gale, R. (1987). The metabolic cost of fever. Canadian Journal of Physiology and Pharmacology, 65(6), 1248–1254.
- Centers for Disease Control and Prevention. (2010, December). The flu – Caring for someone sick at home. Retrieved from
- Centers for Disease Control and Prevention. (2018a, August 27). How flu spreads.
- Centers for Disease Control and Prevention. (2018b, September 4). Selecting viruses for the seasonal flu vaccine.
- Centers for Disease Control and Prevention. (2019, September 17). Flu vaccine safety information
- Centers for Disease Control and Prevention. (2020a, March 18). Suffering from a cold?
- Centers for Disease Control and Prevention. (2020b, September 23). Practice good health habits.
- Centers for Disease Control and Prevention. (2020c, October 1). Preliminary in-season 2019-2020 flu burden estimates.
- Eccles, R. (2005). Understanding the symptoms of the common cold and influenza. The Lancet Infectious Diseases, 5(11), 718–725.
- Francino, M. P. (2016). Antibiotics and the human gut microbiome: Dysbioses and accumulation of resistances. Frontiers in Microbiology, 6, 1543.
- Heikkinen, T., & Järvinen, A. (2003). The common cold. The Lancet, 361(9351), 51–59.
- InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Flu: Overview. 2013 Dec 18 [Updated 2019 Nov 7].
- InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Common colds: Overview. [Updated 2020 Oct 8].
- Merck Manuals. (n.d.). Common cold. Public Health Agency of Canada. (2020, January 7). FluWatch annual report: 2018-19 influenza season.
- Ray, J. J., & Schulman, C. I. (2015). Fever: suppress or let it ride? Fever: Suppress or Let It Ride?. Journal of Thoracic Disease, 7(12), 633–636.
- Smith, J. (2015). A is for aphorisms – feed a fever, starve a cold? Or could it be starve a fever, feed a cold? Aust Fam Physician, 44(1–2), 77–78.
- Wang, A., Huen, S. C., Luan, H. H., Yu, S., Zhang, C., Gallezot, J.-D., … Medzhitov, R. (2016). Opposing effects of fasting metabolism on tissue tolerance in bacterial and viral inflammation. Cell, 166(6), 1512–1525.
- Centers for Disease Control and Prevention. (September, 2019). Flu Symptoms & Complications.
- Centers for Disease Control and Prevention. (December, 2019). Cold versus flu.
- Jacobs, S. E., Lamson, D. M., George, K. S., & Walsh, T. J. (2013). Human rhinoviruses. Clinical Microbiology Reviews, 26(1), 135-162.
- Merck Manuals, & Tesini, B. L. (2020). Common cold.
- Merck Manuals, & Tesini, B. L. (2020). Influenza.
- World Health Organization. (November 2018). Influenza (seasonal). Centers for Disease Control and Prevention. (March, 2019). Clinical signs and symptoms of influenza.