What are the most common causes of viral pneumonia in adults?

Viral pneumonia in adults is most commonly caused by influenza and adenovirus. Influenza is a well-known respiratory virus that can lead to severe inflammation of the lungs and is particularly associated with pneumonia, especially during seasonal outbreaks. Adenoviruses, while less recognized by the general public, can also cause significant respiratory illnesses, including pneumonia, and are responsible for a range of infections, especially in younger or immunocompromised individuals.

The other options consist of viruses that typically do not present as the primary agents of pneumonia in adults. Hepatitis A and B viruses are primarily associated with liver disease rather than respiratory infections. Coxsackie viruses, while they may cause respiratory symptoms, are more commonly linked to hand, foot, and mouth disease or myocarditis. Herpes simplex and cytomegalovirus (CMV) are more often associated with opportunistic infections in immunocompromised patients and are not the leading cause of viral pneumonia in the general adult population.