So far this season, 37 children have died from the flu, according to the latest data from the Centers for Disease Control and Prevention—more than at this time in 2016 and 2017, though fewer than those at this point in 2015. Children are also being hospitalized at higher rates this year than in the two previous years.

But because it can take time for information to reach the CDC, the true number of flu deaths in kids right now could be twice as high as reported, says Dan Jernigan, M.D., M.P.H., director of the CDC’s influenza division.

Some children—those who are younger than 5 or have an underlying condition such as asthma or diabetes—are at high risk for serious flu complications such as pneumonia and sepsis.

But this year, as in most years, about half the kids who have died from flu have been otherwise healthy, according to the CDC.

Typically, between 80 and 85 percent of youngsters who die from flu received no flu shot. “Most children who are hospitalized or become critically ill or die from flu are unvaccinated,” says Wendy Sue Swanson, M.D., a pediatrician at Seattle Children’s Hospital.

Also, even healthy young children’s immune systems are only moderately effective at fighting infection, Swanson says. They haven’t had time to build up any immunity to flu—which is acquired over years of getting flu shots and being exposed to influenza. And the strain of flu that has predominated so far this season, H3N2, has historically caused more hospitalizations and deaths than other strains, especially in children and older adults.

Although the headlines have been worrisome, experts still caution parents not to panic. Knowing which children may be most likely to experience serious flu complications and taking the most effective protective steps for the entire family can go a long way in reducing your child’s risks. Keep in mind that the vast majority of youngsters recover quickly. But to make sure that happens, here’s what every parent must know:

Make Sure They’re Vaccinated

The flu vaccine is the most important step in protecting kids from the flu, and it’s not too late to get the flu shot for your youngsters (and yourself) if you haven’t already. Call ahead to your doctor’s office or pharmacy to make sure the vaccine is available. You can also use the CDC’s Vaccine Finder tool to locate pharmacies in your area that still have the flu shot. Note that only some states allow children to receive vaccines in pharmacies—call your doctor’s office or your local health department if you’re unsure.

Don’t be discouraged by reports of low vaccine effectiveness for the flu shot this year, Swanson says. (Early estimates by government officials suggest that the vaccine may be roughly 30 percent effective against the H3N2 strain.)

As Swanson points out, this means that about one in three people, including kids, who get a flu shot won’t get the illness. If vaccinated children get the flu anyway, it is likely to be milder: A 2016 study looking at recent flu seasons in Ontario, Canada, found that vaccination reduced the likelihood that a child would be hospitalized for flu. Plus, the flu shot is usually more effective against strains that circulate later in the season.