Symptoms of Flu: Symptoms of flu include fever (usually high), headache, extreme tiredness, dry cough, sore throat, runny or stuffy nose, and muscle aches. Gastrointestinal symptoms, such as nausea, vomiting, and diarrhea, are much more common among children than adults.

How Flu spreads: Influenza viruses are spread when a person who has the flu coughs, sneezes, or speaks and spreads virus into the air, and other people inhale the virus. When these viruses enter the nose, throat, or lungs of a person, they begin to multiply, causing symptoms of the flu. The viruses can also be spread when a person touches a surface with flu viruses on it (for example, a door handle) and then touches his or her nose or mouth.
A person who is sick with the flu can spread viruses - that means they are contagious. Adults may be contagious from 1 day before developing symptoms to up to 7 days after getting sick. Children can be contagious for longer than 7 days.

Source: Centers for Disease Control and Prevention

Influenza prevention tips

Influenza shots | Nasal mist vaccine (Vaccine Information Sheet/ CDC)

Should you get a flu shot or the nasal mist? Check our comparison chart