ignore it if asymptomatic. minor symptomatic. mild

however if moderately or severely sick with any illness your body when under strain decide to turn off or dampen bodily functions so it can concentrate on fighting the infection
this is why you stop feeling hungry. because your body has slowed down your digestive system. why you can be less horny. because your body has slowed down your hormone production. its why your more irritable and why your not making as much sperm

but once your body is recovered your hormone and body functions speed back up
so relaxed.. your not infertile.. your just temporarily drained