In response to your second question, I do not know of any positive purpose the influenza virus serves on an individual person basis. Historically, the 1918 influenza pandemic may have helped bring WWI to a close, at the cost of many lives. The flu hit the front lines across Europe in the first wave of infection. Influenza weakened and cut the numbers of fighting forces, leading to a need for more diplomatic tactics. I am not sure this is exactly a positive outcome because millions of people died from complications related to the flu, but it did help end a global war.

Besides getting a flu shot, wash, wash and wash the hands. I wear a mask in enclosed spaces (I am older and at higher risk for a "Bad" outcome). Since you can spread the virus before you have symptoms, I don't want to feel responsible for getting family or friends sick. Especially since I have family with health issues.

The first and best way to protect yourself and your family from flu is to get an annual flu vaccine (https://www.cdc.gov/flu/prevent/vaccinations.htm). There are also everyday preventive actions you can take, like avoiding people who are sick, staying home when you are sick, covering your coughs and sneezes, and washing your hands for at least 20 seconds with soap and water (https://www.cdc.gov/flu/prevent/prevention.htm). You can also consider wearing a well-fitting mask which may help reduce the spread of respiratory viruses. Finally, it’s important to know that if you do get sick with flu, there are prescription antiviral drugs (https://www.cdc.gov/flu/treatment/treatment.htm) that can be used to treat your flu illness. Treatment works best if started within 2 days of illness onset. However, starting them later can still be helpful, especially if the sick person has a higher-risk health condition or is very sick from flu (for example, hospitalized patients). Follow your doctor’s instructions for taking these drugs.