The flu is now widespread in all but seven states across the United States.
According to federal authorities, flu activity has been more intense this year compared with recent seasons.
At Premier Care in Syosset, staff says the waiting room has been busy all month.
"Over the past two or three weeks, there has been a tremendous increase with the number of patients we are seeing with the flu," said Michael Grosso, of Huntington Hospital.
Symptoms of the flu include fever, headaches, tiredness, dry cough, runny nose and muscle aches. Doctors say flu patients should stay home, hydrate and get plenty of rest.
Doctors say people can tell the difference between the common cold and the flu because the flu starts very suddenly and symptoms are more intense.