Doctors are calling this flu season the worst in the last 15 years – reflected in a high number of cases in the tri-state area and 40 other states.

Data from the CDC has found that hospitalizations and deaths have also increased. Those who are at risk the most of getting the flu are seniors and people with compromised immune systems.

Doctors say it's important for people to know the difference between typical symptoms, such as high fever, muscle aches, body pain and headache, and what are considered red flag symptoms (persistently high fever, shortness of breath or difficulty breathing).

Red flag symptoms could mean someone is developing a serious lung infection and may need emergency medical care.

At-home flu tests are available to purchase online or in stores. They test for influenzas A and B along with COVID-19.

Officials say it's not too late to get a flu shot if you are at risk for contracting flu complications. They add it takes two weeks for its immunity to kick in and will protect people for the rest of flu season which goes through April.