From the Guidelines
The flu typically lasts around 5 days, with some symptoms like cough and malaise persisting for up to 2 weeks, as indicated by the average duration of uncomplicated influenza illness 1. The illness usually begins with the abrupt onset of constitutional and respiratory signs and symptoms, such as fever, myalgia, headache, severe malaise, nonproductive cough, sore throat, and rhinitis, with an incubation period of 1-4 days and an average of 2 days 1. Some key points to consider about the flu duration include:
- The incubation period for influenza is 1-4 days with an average of 2 days 1
- Persons can be infectious starting the day before symptoms begin through approximately 5 days after illness onset; children can be infectious for a longer period 1
- Uncomplicated influenza illness is characterized by the abrupt onset of constitutional and respiratory signs and symptoms 1
- Illness typically resolves after several days for most persons, although cough and malaise can persist for 2 or more weeks 1 For symptom management, rest, hydration, and over-the-counter medications can help reduce fever and relieve pain, and antiviral medications may shorten illness duration by 1-2 days if started within 48 hours of symptom onset. The flu's duration relates to how long it takes your immune system to clear the viral infection, with symptoms reflecting both the virus's effects and your body's immune response, and most people recover without complications, but those with severe symptoms, breathing difficulty, or in high-risk groups should seek medical attention promptly.
From the Research
Flu Duration
- The duration of flu symptoms can be decreased by approximately 1 day with the use of neuraminidase inhibitors such as zanamivir and oseltamivir, if initiated within 48 hours of the onset of symptoms 2.
- Clinical studies have shown that these inhibitors can limit the extent of infection and speed recovery from illness by inactivating viral neuraminidase, an enzyme responsible for cleaving sialic acid residues on newly formed virions 2.
- Meta-analyses of observational studies suggest that oral oseltamivir may reduce the duration of symptoms by 33 hours compared to no treatment, although the quality of evidence is very low 3.
- Inhaled zanamivir may lead to shorter symptom duration by 23 hours compared to no treatment, with moderate-quality evidence 3.
- The decision to use these agents should be based on factors such as the age of the patient, antiviral activity, side effect profile, ease of administration, drug interactions, and cost 4.