Health issues can also pop up well after a flight. Flew on EK85 end of August, and a few days back received an email from the Swiss health authorities. Surprisingly not a word from EK, although the authorities must obviously have received the pax contact details from EK) reporting that passengers with measles had been on board and advising on the symptoms, risk categories and what to do if infected (given the long incubation period for measles, others may have contracted it without yet realizing it yet, a good 2 weeks after the flight). I assume a number of pax must have fallen sick for the health authorities to have sent out their message. Luckily, had my shots as a kid!