Pneumonia can occur in just one lung or both. When pneumonia occurs in both lungs, it is called double pneumonia. The thing is that pneumonia can be silent. In fact, it can be so mild it might not be noticed, as in the case of walking pneumonia.

Some have a higher risk of developing pneumonia than others. According to the Mayo Clinic, your risk of getting pneumonia increases if you have a chronic disease-like asthma or heart disease. In addition, those with weak immune systems have a higher risk of getting pneumonia. This can include those who are in chemotherapy or those have HIV/AIDS. Further, smoking increases the risk of developing this illness. And your risk is elevated if you’re hospitalized (particularly if you’ve been placed on a ventilator).

There are two types of pneumonia: viral and bacterial. And both can present with differing symptoms. Viral pneumonia usually results in coughing without mucus. But bacterial pneumonia often presents with mucus and at times a high fever. Further, viral pneumonia is usually milder than bacterial pneumonia, making hospitalization less likely.  

According to the American Lung Association, the symptoms of pneumonia can be either mild or severe. This depends on how healthy you are, what type of pneumonia you have, and how old you are. However, most commonly, the symptoms of pneumonia include: a cough which may be green or yellow and may include bloody mucus, a fever, noticeable shortness of breath upon physical exertion (like climbing the stairs), and the chills. 

That said, other symptoms can occur. These can be: chest pain that elevates if you take a deep breath or cough, a headache, sweating, clamminess, tiredness and decreased energy, a lack of appetite, and confusion (which is most common in those who are older).

Interestingly pneumonia can be spread to others. This can occur through coughing, sneezing, and breathing. That’s why experts advise those who have pneumonia to limit contact with others.