Lung infection (pneumonia) caused by the chickenpox virus is an uncommon complication of chickenpox. It develops when the chickenpox virus travels to the lungs.

Varicella pneumonia can occur 2 to 10 days after the chickenpox rash. Although fever and cough are usually the first signs of pneumonia, some people have no symptoms.

Most people recover from varicella pneumonia. But the symptoms may last for weeks or months.

When it occurs, varicella pneumonia tends to affect:

• Teens and adults. Teens and adults are more likely to develop varicella pneumonia than children. Adults who develop this condition may become very sick. Varicella pneumonia is the most common cause of death in adults who get chickenpox.
• Pregnant women. Pregnant women who have chickenpox during the last part of pregnancy are at risk for getting varicella pneumonia, which can lead to severe illness or death.
• People with lifelong (chronic) lung diseases. People with chronic lung diseases are more likely to develop pneumonia if they have chickenpox.
• People with impaired immune systems. Varicella pneumonia is most common in adults and other people with impaired immune systems.
• People who smoke cigarettes. They are more likely to get varicella pneumonia than people who do not smoke.¹