symptoms usually last 3–7 daysTrusted Source. Some people find that their symptoms get better and then worse again or that they are worse at certain times of the day, such as in the morning.
the most severe symptoms typically resolve within a week, some people have low energy for up to 2 weeks, and it is possible to experience a cough for up to 8 weeks.
people who still get the flu after receiving a shot tend to have less severe symptoms that last for a shorter period.
Antiviral drugs, such as oseltamivir (Tamiflu), can also shorten the length of the flu and lower the risk of serious complications.
Infants and very young children, older adults, and people with respiratory diseases may have symptoms that last longer.
The symptoms tend to peak between days 2 and 4. By day 5, some people begin to feel better. A few feel well enough to return to work or school.