The respiratory bugs that surge every winter, from respiratory syncytial virus (RSV) to whooping cough, hit us with nasty coughs, fevers and chills—and they can also create the perfect opportunity for deadly pneumonia.

Often misunderstood as a single sinister ailment (one your parents have ominously warned that you’d catch if you forgot your coat), pneumonia actually describes a lung infection that can be caused by any of about 30 different pathogens. It is among the leading causes of death in people older than age 70 or under age 5. And it can be fatal in anyone with a compromised immune system or other disorders that put them at high risk.