In an article by my friend and geriatrician, Leslie Kernisan, “Flu Shots for Older Adults What to Know,” she offers useful advice about influenza vaccinations.

When Dr. Kernisan worked in a primary care clinic, they made a big push for all patients to get a seasonal flu shot and not all clients agreed. They were skeptical of the need and not convinced the shot helps.

The physician reminds us of the CDC flu estimates that affect millions of Americans every year. In the years 2015-2016 the influenza affected 9 million-60 million Americans, caused 140,000-710,100 hospitalizations, which resulted in 12,000-56,000 deaths. Most individuals do recover without hospitalization, but some get very sick. Older adults are more likely over any other age group to get dangerously ill when having the flu. Learn the basics:

Q. What is influenza?

It is a contagious respiratory viral illness which causes a sore throat, stuffy nose, cough, fever, and body aches. An uncomplicated flu can get better over 5-7 day period. In the Northern hemisphere, influenza is most common in the winter. Peak influenza activity usually occurs between December and February, but it can start as early as October and occur as late as May.

However, influenza can cause more serious health problems for older people living with chronic conditions, or a weakened immune system. The most common complication of influenza is pneumonia.

Q. How does the flu shot help protect one from influenza?

The vaccine works by stimulating the body to produce antibodies against whatever strains are included in that year’s vaccine. It takes about two weeks for the body’s immune system to create its influenza antibodies after receiving the shot. The body is then more able to fight infection more quickly. If we don’t have matching antibodies, then we’ll experience more illness, and it will take longer for our immune systems to control the infection.

Since both influenza A and B can change into slightly different strains, it’s harder for scientists to predict what strains are present and which ones will expose the public.

Q. Can you get the flu from the flu shot?

No, you cannot. The recommended vaccines in the market today have an inactivated virus (meaning the germ is not living) or recombinant technology (meaning they cobbled together virus proteins. It is not possible for these vaccines to give you influenza.

You get the virus by breathing air droplets containing influenza virus or when infected people talk, sneeze or cough. The person may be contagious for one day before developing symptoms, and 5-7 days after getting sick. Plus, the virus survives on hard surfaces for up to a day and less on soft ones like towels.

Carol Marak is an aging advocate and editor of Seniorcare.com.