As COVID-19 pneumonia worsens, more of the air sacs fill with fluid spilling from the lungs' small blood veins. Shortness of breath eventually sets in, which can lead to acute respiratory distress syndrome (ARDS), a kind of lung failure. Most people will recover from COVID-19 without needing any special treatment for their lungs. People who suffer from chronic diseases such as diabetes or heart disease are at greater risk of suffering complications from COVID-19. They should take special care not to overextend themselves physically or mentally during this period. Their health care providers should monitor them closely for symptoms and act quickly if they notice any changes in behavior or breathing patterns. People who have recently undergone surgery or are immunocompromised because of medications or illness may be at increased risk of developing serious complications from COVID-19. It is important that they follow proper hygiene practices until they heal from their operation or recover from their current illness. If they show signs of illness, they should contact their health care provider immediately so they can get advice about whether they need to stay home or go to a hospital. People who have been exposed to COVID-19 but do not have any signs of illness themselves should still practice social distancing and avoid being around others if at all possible.