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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.
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)
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.