Sickly folk are contagious for a long time. An adult can spread the virus one day before and three to seven days after symptoms show. Kids are contagious for even longer periods of time. Although you can steer clear of those that sniffle , some infected individuals show no symptoms and can still spread the virus to others.
Most commonly, the virus travels through the air in liquid droplets from coughs and sneezes. Viruses prefer the wintry conditions of cold air with low humidity. In humid air, the droplets grow heavy with water and fall to the ground—or to other surfaces.
To avoid the flu altogether, your best shot is to move to the tropics. Flu season is virtually nonexistent in those hot and humid conditions.
If you do fall ill, you can avoid transmitting the flu by following these steps from Harvard Medical School.
Always cover your mouth and nose when you sneeze or cough.Throw used tissues away immediately.Wash your hands often , especially after you sneeze, cough, or touch your eyes, nose, or mouth.Keep your distance from others — don’t kiss, hug, or stand so close to someone that saliva might get on them when you talk.Make sure someone is disinfecting household surfaces and items frequently, including children’s toys.
Some of these tips, especially the hand-washing, are also useful prevention measures if you're feeling just fine.