The severity of the flu can vary from person to person, but in general, the worst symptoms of the flu tend to occur three to four days after a person has been infected by the virus. During this period, symptoms such as fever, chills, body aches, fatigue, and sore throat are all at their peak. As the body begins to fight off the virus, the symptoms usually start to improve, though they can still linger for several days afterwards. It is important to remember that the flu is contagious for up to a week after symptoms first appear, so it is important to take necessary precautions to prevent spreading the virus to other people.
At any stage of the flu, it is important to get plenty of rest, drink lots of fluids, and take over-the-counter medications, such as ibuprofen, to help reduce symptoms. However, if symptoms persist for more than a couple of days, it is important to seek medical attention to prevent any further complications.