Can someone get legionnaires disease more than once?

Yes: This is a lung infection from inhaling (not person to person contact) the legionella bacteria. Most outbreaks are from plumbing systems in poorly maintained buildings or through contaminated soil (such as gardeners). Like any bacterial infection it can recur. Risk of recurrence increases if you smoke, are older (65 years), have chronic lung disease or repeated exposure.

Yes: Stay away from air conditioners or avoid contacts.