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- Centers for Disease Control and Prevention: Types of Influenza Viruses
- CDC: Flu Symptoms and Severity
- MedlinePlus: Flu
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Type A and Type B influenza cause the same set of symptoms, and protection against both types is included in the flu vaccine that scientists develop each year. According to the Centers for Disease Control and Prevention, there's also a third type of influenza virus, Type C, which causes only mild respiratory symptoms and is not included in the annual vaccine 1. Type A influenza causes all the standard flu symptoms that you're probably familiar with.
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
The first symptoms that many people notice when they have Type A influenza include chills and fever, which can reach as high as 103 degrees Fahrenheit (39 degrees Celsius). Not everyone with the flu experiences a fever, however. Other early symptoms often include fatigue, muscle aches and pains, headache and an overall sense of being unwell. Symptoms typically begin about 1 to 4 days after you've been infected with the flu virus.
Influenza Virus Characteristics
The flu's respiratory symptoms often appear shortly after the early symptoms. These typically begin with a dry, unproductive cough and sore throat. Some people -- but not all -- experience a runny or stuffy nose. Some people may develop a productive cough and wheezing. Symptoms of the flu typically resolve in 1 to 2 weeks, but in some people, the cough and wheezing can persist for up to 8 weeks.
A few people may experience nausea, vomiting and diarrhea with influenza, but this is not as common as other symptoms. If these are your main symptoms and you have what people commonly describe as stomach flu, you don't have Type A influenza at all but rather an infection called gastroenteritis.
Type A and Type B influenza cause the same set of symptoms, and protection against both types is included in the flu vaccine that scientists develop each year. The first symptoms that many people notice when they have Type A influenza include chills and fever, which can reach as high as 103 degrees Fahrenheit . Other early symptoms often include fatigue, muscle aches and pains, headache and an overall sense of being unwell.
Influenza Virus Characteristics
Causes of a High Fever and Runny Nose
General Flu Symptoms Without Upper Respiratory Symptoms
What Is the Incubation Period for the Flu?
Signs & Symptoms of Type A Influenza
Can Allergies Cause Flu-Like Symptoms?
Influenza B Signs & Symptoms
What Is the Difference Between Influenza A & B?
Flu-Like Symptoms After a Flu Shot
About Type B Strain Flu
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