A look at pneumonia facts after Clinton's recent diagnosis

It's the video that's got many people talking. Hillary Clinton nearly collapses in New York. She's admitted she's been diagnosed with pneumonia. What does that mean? How serious is it?

Henry Ford Health System Family Practitioner Dina Ibrahim has some answers.

She says pneumonia is an infection of the lung that can be life threatening. It impairs the person's ability to breathe, and they'll feel sick and tired.

Clinton works very closely with a lot of people on the campaign trail. Pneumonia is a contagious illness, usually spread by airborne droplets.

"(It's passed) if someone sneezes or coughs in your area, or you touch a door knob after they just sneezed or coughed in their hand," Ibrahim said.

The illness is a bigger concern for older people, as the immune system starts to slow down after the age of 65.

Ibrahim said it can take anywhere from a few days to a few weeks to recover, depending on the severity of the illness.

The doctor said other than people over the age of 65, those 19 years of age and older with asthma, diabetes, and kidney, liver or heart failure issues need a vaccine.