These are the top risk factors for severe flu, according to the CDC

Cases of the flu are slowly ramping up across the country as we head into the holiday season. With that comes the risk of developing severe flu.Video above: How to boost your immune system before flu seasonThe Centers for Disease Control and Prevention (CDC) just released a report breaking down the factors that increase your risk of developing severe flu, based on data from people who were hospitalized with the illness from 2010 to 2023. The findings clearly spell out what can raise your odds of severe flu, along with a few things you may be able to modify to reduce your risk. Flu causes up to 41 million illnesses and up to 51,000 deaths each year, making it an important infection to have on your radar. But what is classified as severe flu, and what are the risk factors for developing it? Here’s what doctors say.What is severe flu?At baseline, the flu—which is also known as influenza—is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs, per the CDC. But plenty of people can have what’s considered a mild case of the flu—meaning, they didn’t feel amazing, but they didn’t need to be hospitalized. “The tipping point for severe flu really is whether you have to go to the emergency room or be admitted to the hospital,” says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. This category also includes people who died from the flu, even if they didn’t go to the hospital, says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. What are the risk factors for severe flu?The CDC report analyzed data from laboratory-confirmed flu-related hospitalizations in children and adults between 2010 and 2023. It noticed a few trends in risk factors for severe flu. Those include: Age: Young children and older adults are at most risk. Not being vaccinated: People who weren’t vaccinated against the flu were much more likely to be hospitalized with the infection. Neurological conditions: Having cerebral palsy, epilepsy, and other neurological disorders may make it difficult to remove fluid from the airways. Lung disease: People with underlying respiratory conditions, including chronic obstructive pulmonary disease (COPD), can develop trouble breathing from the flu. Heart disease: About 50% of patients hospitalized with flu had heart disease. Pregnancy. During pregnancy, the immune system is suppressed, making it harder to fight off infection. High blood pressure: Hypertension, or high blood pressure, stresses the cardiovascular system. That stress can be worse with the flu, Dr. Schaffner says. Obesity. People with obesity may have other underlying conditions like type 2 diabetes or high blood pressure that can be made worse by the flu. “Obesity is a critical risk factor for severe disease,” Dr. Russo says.How do I lower my risk for severe flu?Doctors stress the importance of vaccination. Research shows that less than half of eligible Americans actually got the flu shot last year. “Get vaccinated,” Dr. Schaffner says. “The vaccine reduces your risk of severe flu and ending up in the hospital.” Dr. Russo agrees. “Vaccines are our best defense against severe flu,” he says. Dr. Russo also recommends doing your best to avoid people who are obviously sick. “A combination of hand hygiene and appropriate mask use can also decrease the likelihood you’ll get infected,” he says. N95 and KN95s may help protect you from respiratory droplets. If you have any underlying health conditions that put you at risk of severe flu, doing your best to keep them well-managed can also lower your risk, Dr. Russo says. When to see a doctor If you’re considered high risk for severe flu, Dr. Schaffner recommends having a “low threshold” for calling the doctor if you get sick. “We have antiviral medications, including Tamiflu, that can help prevent severe flu,” he says. “We can provide some treatments to help keep you out of the hospital.”But Dr. Russo says it’s important for everyone to stay on top of their symptoms if they develop the flu. If you develop shortness of breath, are wheezing, have blueness in your lips, are dizzy, or feel confused, you should get checked out ASAP.