Because flu cases often peak in February, vaccination in November or later still can be valuable. The CDC this year recommended that people 50 to 64, not just those 65 and older, be vaccinated. Anyone with an immune disorder or any woman in the second or third trimester of pregnancy also should be a priority, CDC says. In all, as many as 76 million people are at high risk for serious complications from the flu, which commonly leads to 20,000 deaths and more than 110,000 hospitalizations each year. The flu infects the respiratory tract and can cause high fever and major complications including pneumonia, which can be deadly.
Flu spreads through the air from sneezing and coughing or through close physical contact.