Following reports that former New York City Mayor Rudy Giuliani, 81, was hospitalized with the condition this week, it might be time for your semi-regular reminder of the very real risks of pneumonia — which can be particularly deadly for individuals 65 and over.

Pneumonia is considered a common bacterial lung disease leading to 225,000 hospitalizations each year, according to the American Lung Association (ALA) — but one group is 10 times more likely to hospitalized with the condition than other adults and significantly more likely to face deadly outcomes.

“A pneumonia implies that there is an infection resulting in inflammation in the lung tissue,” Dr. Panagis Galiatsatos, assistant professor at the Johns Hopkins School of Medicine and author of “Medicine for the Greater Good: Achieving the Promise of Medicine Through Community Engagement,” told HuffPost. “Pneumonia means an infection has infiltrated that area and is causing inflammation. Our lungs are not sterile. There’s a big microbiome in there. That microbiome sits there pleasantly fine, not causing inflammation. But when an infection does that, that’s a pneumonia.”

Why are elderly populations at such a high risk of complications?