In flu season, i hear certain sick people are supposed to avoid crowded places because they'd more likely die. are people recovering from pe included?

Of course: It is a reliable fact that crowds will include persons carrying a variety of infectious agents that can pass through airborne droplets or casual contact. Any person with frail health or recovering from a significant problem like a PE should try to reduce their exposures. Shopping at off hours & avoiding crowded public transport is a good idea.