It can be difficult to tell if you have a common cold or seasonal influenza based on symptoms alone. Both respiratory illnesses share similar symptoms but are caused by different viruses. Comparing the two illnesses may help you differentiate whether you have a cold or flu this season.
Causes
More than 200 different viruses can cause the common cold. This makes it impossible to find a cure. Rhinoviruses cause an estimated 30 to 50 percent of all colds.
More than 100 distinct rhinovirus types have been identified. Coronaviruses cause about 10 to 15 percent of adult colds, primarily in the winter and early spring. (1)
There are three types of influenza viruses. Human influenza A and B cause seasonal epidemics of influenza each winter. The emergence of a new and different strain of influenza virus leads to an influenza pandemic.
Influenza C virus causes a mild respiratory illness and is not thought to cause epidemics. Influenza A viruses are divided into subtypes, such as H1N1, which emerged in the spring of 2009 to infect many people. Influenza B viruses are divided into strains. (2)
Symptoms
The onset of common cold symptoms is usually two to three days after exposure to the virus. A runny or stuffy nose, sneezing, congestion, sore throat, watery eyes, cough, slight body aches or a mild headache, low grade fever and mild fatigue are typical symptoms of a cold. Nasal discharge may be become thicker and yellow or green in color as the cold runs its course.
Generally, you do not have a high fever or significant fatigue with the common cold. (3) Symptoms can last from 2 to 14 days, while most people recover in a week to 10 days. (1)
Seasonal influenza symptoms come on suddenly. While not everyone with the flu has a fever, a fever of over 100 degrees Fahrenheit or 38 degrees Celsius with chills is a possible symptom. A runny or stuffy nose, sore throat, cough, muscle and body ache, fatigue and headache are commonly experienced symptoms. Vomiting and diarrhea are flu symptoms that commonly occur in children but may be experienced by adults.
Most individuals recover in a few days to less than two weeks. Others may develop complications such as pneumonia. In some cases, influenza leads to life-threatening complications and even death. (2)
Transmission
The viruses which cause the common cold and seasonal influenza are spread mainly by airborne transmission. When an infected person coughs, sneezes or talks, the viruses travel in droplets. The droplets can land on the nose or mouth of an uninfected person. Inhaling the droplets is a common way these illnesses are transmitted.
The common cold is spread by touching an object, such as the handle of a shopping cart or the handrails on a subway car, that has the cold viruses on it and then touching your eyes or nose. Less often, a person can catch the flu this way.
Prevention
The common cold and seasonal influenza are highly contagious respiratory illnesses. An ounce of prevention is worth a pound of cure. Frequent and thorough hand washing is a good preventive measure to protect you against both illnesses. If soap and warm water are not available, use an alcohol-based hand sanitizing product.
If possible, avoid people with a cold or the flu. If you are sick, avoid contact with others. When you sneeze or cough, cover your nose or mouth and sneeze or cough into your elbow, instead of your hand.
The rhinoviruses can survive up to three hours on your skin and objects. Disinfect environmental surfaces, such as telephones, door knobs and hand rails, with a virus –killing disinfectant when someone has a cold or the flu. (1)
The CDC recommends an annual flu vaccine as the first and most important step in protecting against the flu viruses. Everyone six months of age and older is advised to get a flu vaccine as soon as the 2011-2012 vaccines are available. (2)
Sources:
(1) National Institute of Allergy and Infectious Diseases: Common Cold, Nov. 18, 2011
http://www.niaid.nih.gov/topics/commonCold/Pages/overview.aspx
(2) Center for Diseases Control and Prevention: Seasonal Influenza: Flu Basics, Nov. 18, 2011
http://www.cdc.gov/flu/about/disease/index.htm
(3) Mayo Clinic: Common Cold/ Symptoms, Nov. 18, 2011
http://www.mayoclinic.com/health/common-cold/DS00056/DSECTION=symptoms
Reviewed November 21, 2011
by Michele Blacksberg RN
Edited by Jody Smith