Everyone who is 65 or older should get a flu shot every year in the fall. The flu virus changes from year to year, and the vaccine changes to match the new virus. Adults of any age who want to be protected against the flu should get a yearly flu shot. You cannot catch flu or pneumonia from the shots. You cannot tell by looking at someone if he or she has it.
Most people have no signs of the disease at all.
The only way to know for sure is to get a blood test. Some people are at high risk and should get three shots of vaccine. Hepatitis A is also a liver disease. It can make you sick for several weeks or months. It takes two shots to be fully protected.