The spread of the flu can stop with anyone who gets a flu shot.

Modeling from the Centers for Disease Control show the flu vaccine prevented 5.1 million cases of the flu in the U.S. during the 2015-16 flu season, 2.5 million flu-related medical visits that season, 71,000 hospitalizations and an estimated 3,000 pneumonia and influenza deaths.

“Your decision to get a flu shot could keep you from being that person who passes the flu around to everyone at the office, school, or the gym,” said Richard Vienne, Univera Healthcare vice president and chief medical officer. “Your decision to get a flu shot could keep you from passing it to someone whose body isn’t resilient enough to defend against the illness’s most deadly consequences.”

For some people, the flu results in a fever, the chills, body aches and a runny nose. But for the very young, the very old, women who are pregnant, and individuals with compromised immune systems, catching the flu places them at high risk for serious complications, including death.

“Unfortunately, it’s not always obvious who among us is most vulnerable,” Vienne said.

One person with the flu can infect other people one day before any symptoms develop, and up to about seven days after they become sick. The virus can spread to others up to about 6 feet away, mainly by microscopic droplets expelled into the air when people cough, sneeze or even talk. Every 100 people who get the flu can pass it on to 127 other people, according to the journal BMC Infectious Diseases.

The CDC recommends annual flu vaccines for everyone 6 months and older.

According to Vienne, it takes about two weeks for the flu vaccine to provide protection, and it’s never too early or too late in the flu season to get a flu shot.