THE NEW YORK TIMES – Sore throat. Stuffy nose. Fever, body aches and fatigue.
For many people, the immune system can clear those symptoms in about a week. But for others, flu can lead to severe illness, hospitalization or even death. Flu infections cause up to 710,000 hospitalizations and 51,000 deaths every year in the United States, according to the Centers for Disease Control and Prevention.
A recent analysis by the CDC unpacks some of the factors that put people most at risk of severe health outcomes.
Age: Young children and older people are consistently hospitalized with the flu at the highest rates because their immune systems are less robust than those of older children or younger adults, meaning they are less capable of fending off infection.
There are two types of flu viruses that can wreak havoc every season: Type A and Type B. The highest hospitalization rates since 2010 occurred during flu seasons when influenza Type A viruses were predominant; the C.D.C. has said this is because older adults tend to be more affected by H3N2, a Type A virus.
Neurological disorders: Some children with neurological conditions such as epilepsy and cerebral palsy may have trouble with muscle and lung function, and may have trouble coughing or clearing fluids from their airways. This can exacerbate flu symptoms or lead to pneumonia.
Lung diseases: Flu can set off asthma attacks in children with the condition, which causes chronic inflammation of the airways. It can also lead to pneumonia and other respiratory issues that can require hospitalization.
In adults with chronic obstructive pulmonary disease, who have an impaired immune response, the body can have a harder time clearing a bout of flu. An infection can also further inflame the airways, making it even more difficult for patients to breathe.
Obesity and chronic metabolic diseases: For both children and adults, obesity is a risk factor for severe illness from flu. That may be because of several different factors. Excess weight can make it more difficult to take the deep breaths needed to clear an infection from the lungs, for example, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center.
