Democratic presidential candidate Hillary Clinton’s recent bout with illness earlier this September brought new attention to pneumonia.

Clinton appeared to recover swiftly and returned to the campaign trail. If you're interested in the basics about the disease, Medical Daily has covered them. But perhaps the most important question is, how long will you be sick?

A Disease Of Many Causes

The short frustrating answer is: It depends.

That’s because pneumonia is simply the term doctors use to describe an inflammation of the lungs, specifically the air sacs, so there’s no shortage of bacteria, viruses and other microscopic crawlies that cause it (there are even rare non-infectious causes). The severity of pneumonia also varies because certain groups — the very young, elderly, and otherwise immuno-compromised — are less able to fend off whatever bug has decided to call their lungs home.

Typically, bacterial pneumonia is less severe and shorter-lasting than other forms, and unlike viral pneumonia, it responds to antibiotics.

The mildest cases are called walking or atypical pneumonia. They come with a dry cough, mild fever, and shortness of breath, among other symptoms, and are usually recovered from in a few days. Clinton’s personal physician, Dr. Lisa Bardack, didn't disclose the cause of pneumonia that the presidential candidate was suffereing from, but she did state that Clinton was given a course of antibiotics.

On the other end of the spectrum, severe pneumonia can send you straight to the intensive care unit, if not to an early grave, and often requires weeks of intense treatment.

Some of the most common causes of walking pneumonia include Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumonia. To illustrate the complexity of pneumonia, Legionella bacteria can cause both the mild Pontiac fever that leads to walking pneumonia as well as the much more severe and life-threatening pneumonia found in Legionnaires’ disease.

Whether mild or severe, though, it’s probably for the best to see your doctor if you think you’re coming down with the symptoms of pneumonia.