A toddler’s recent death after contracting the flu is a tragic reminder that flu vaccines are available to families. The boy, whose name and exact age were not released by the Orange County Health Care Agency, was the first flu-related death of the season in Orange County, California.

According to health officials, he was healthy before the infection and did not get a flu vaccination. Lab tests confirmed he was infected with influenza A. The virus spreads mainly through droplets from coughs and sneezes. Symptoms can include fever, cough, sore throat, runny or stuffy nose, headaches, body aches, chills and fatigues.

“This is an important reminder that influenza can cause serious illness, particularly in the very young,” County Health Officer Dr. Eric Handler said in a statement. “Everyone over 6 months of age should be vaccinated each year.”

According to the Centers for Disease Control and Prevention, flu season in the U.S. starts as early as October and lasts as late as May. Experts are already worried that this might be a particularly bad flu season for several countries.

Millions of people get the flu every year. About 140,000 to 710,000 people have been hospitalized for flu-related complications since 2010, and deaths have ranged from 12,000 to 56,000, according to the CDC. At least three-quarters of children who have died of the flu between 2010 and 2014 were not vaccinated against the virus before they got sick.

A total of 101 children have died from the flu in the 2016-17 season alone, the organization states.

The best way to reduce your risk of getting sick with the influenza A and B viruses, and spreading them, is to get the seasonal flu vaccine every year. Vaccines are recommended especially for infants and young children, pregnant women, adults over 50 and those with chronic medical conditions. OC Health Care Agency officials also note that those in close contact with these high-risk people should also get vaccinated. (If that sounds like almost everyone, you probably get the hint.)

There are, however, rare cases of people who shouldn’t get the flu shot, including children under 6 months and people with severe, life-threatening allergies to flu vaccine. People who are allergic to eggs or any ingredients in the vaccine or have a history of the severe paralyzing illness Guillain-Barré Syndrome should talk to their doctors before getting the flu shot.

If you do have the flu, remember to cover your cough or sneeze with a tissue or sleeve, wash your hands often with soap and warm water, and stay home for at least 24 hours after your fever is gone.