What's a seasonal flu ?

Seasonal flu (also known as influenza) is a highly infectious [in?fek??s](傳染的)  illness caused by a flu virus [?vai?r?s]（病毒）.

The virus  infects [in?fekts](感染) your lungs and upper airways（上呼吸道）, causing a sudden high temperature and general aches and pains（周身疼痛）.

You could also lose your appetite [??pitait](食欲), feel nauseous [?n?:??s, -zi:?s](想嘔吐的) and have a dry cough. You may need to stay in bed until your symptoms get better.

The influenza vaccine [v?k?si:n?v?k?si:n](疫苗) is the best way to prevent [pri?vent]（預(yù)防） the flu, and flu prevention should be a goal for everyone.

When should I get a flu shot?
Because flu season may begin as early as October and run through May, the best time to get a flu shot is in October or November. You can still get an influenza vaccine in December or later, but earlier may be more beneficial [?beni?fi??l](有利的) in preventing flu.