Influenza history and symptoms
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alejandro Lemor, M.D. [2]
Overview
Influenza illness can include several non-specific symptoms, such as fever, muscle aches, headache, lack of energy, dry cough, sore throat, and possibly runny nose. The fever and body aches can last 3-5 days and the cough and lack of energy may last for 2 or more weeks. The symptoms of the flu are more severe than their common-cold equivalents.
History and Symptoms Adapted from CDC[1]
- The typical incubation period for influenza is 1-4 days.
- Adults shed influenza virus from the day before symptoms begin through 5-10 days after illness onset. However, the amount of virus shed, and presumably infectivity, decreases rapidly by 3-5 days after onset in an experimental human infection model.
- Young children also might shed virus several days before illness onset, and children can be infectious for 10 or more days after onset of symptoms.
- Severely immunocompromised persons can shed virus for weeks or months.
- Uncomplicated influenza illness is characterized by the abrupt onset of constitutional and respiratory signs and symptoms, such as fever, myalgia, headache, malaise, nonproductive cough, sore throat, and rhinitis.
- Among children, otitis media, nausea, and vomiting also are commonly reported with influenza illness. Uncomplicated influenza illness typically resolves after 3-7 days for the majority of persons, although cough and malaise can persist for >2 weeks.
- However, influenza virus infections can cause primary influenza viral pneumonia; exacerbate underlying medical conditions such as pulmonary or cardiac disease lead to secondary bacterial pneumonia, sinusitis, or otitis media; or contribute to coinfections with other viral or bacterial pathogens.
- Young children with influenza virus infection might have initial symptoms mimicking bacterial sepsis with high fevers, and febrile seizures have been reported in 6%-20% of children hospitalized with influenza virus infection.
Common Symptoms
- Body aches, especially joints and throat
- Cough
- Sneezing
- Extreme coldness
- Fever
- Fatigue
- Headache
- Irritated watering eyes
- Nasal congestion
- Nausea and vomiting
- Reddened eyes, skin (especially face), mouth, throat and nose