The flu is putting lots of people in the hospital. Here’s what is going on in Pennsylvania and New Jersey.

With children’s hospitals filling up with respiratory syncytial virus (RSV) and other seasonal illnesses, public health leaders are urging people to stay vigilant about the flu. Hospitalizations related to the illness nationwide are the highest they have been in a decade for this time of year, according to the U.S. Centers of Disease Control and Prevention.

» READ MORE: As respiratory virus cases surge among kids in Philly region, children’s hospitals filling up with ‘young babies that are struggling to breathe’

The states hardest hit by the flu so far are mostly in the south, though New Jersey has also seen high transmission, according to the CDC.

Pennsylvania has relatively low flu activity. In Philadelphia, flu activity has been “a bit higher” than last season through Oct. 22, according to the Department of Public Health. But the city saw an increase in influenza-like illness, particularly among children and adolescents, at the end of the month. And there’s been a “sharp rise” in lab tests in local hospitals that confirmed flu cases.

Philadelphia reported six severe influenza cases in October and one outbreak in a long-term care facility so far this season.

In New Jersey, doctor’s office visits and emergency department visits related to the flu or respiratory illnesses are rising, according to the state’s Department of Health. As of Oct. 29, they are at a level higher than this time last year.

Health authorities and physicians continue to emphasize the importance of the flu vaccines.

Nationally, vaccine uptake for children ages 6 to 17 has been on par with last year. However, roughly five million fewer doses were administered to adults so far this flu season compared with last year.

Children’s hospitals have been flooded with young people suffering from respiratory symptoms associated with RSV. Public health leaders suspect that after two years of masking and social distancing, children are being exposed to viruses for the first time, said José Romero, the CDC’s director of the National Center for Immunization and Respiratory Diseases, during a telephone news briefing Friday.

» READ MORE: Flu and cold season looks different because of the pandemic. Here are some tips to protect kids from viruses this winter.

One of the best ways to protect against influenza is to get the flu shot. The vaccine doesn’t contain live virus, and you cannot get the flu from it. Some people do suffer mild side effects, including arm soreness and fatigue. People who get the flu shot and COVID-19 booster at the same time are more likely to experience side effects.

The flu vaccine is available at doctors’ offices and pharmacies.

If you don’t have insurance, visit a city health clinic, ederally qualified health center, or other community clinic such as the Dr. Ala Stanford Center for Health Equity, to get the vaccine, free.

New Jersey residents can find a local health clinic, many of which provide free or low-cost vaccines, or a federally qualified health clinic at www.nj211.org/get-flu-ready.

» READ MORE: Your flu questions answered.