Does swimming help people with asthma prevent it from recurring in their lives again?

No: Swimming is considered a good exercise for people with asthma but will not prevent or cure it. In fact, there are suggestions that swimming in chlorinated pool may actually cause some people to develop asthma but this study needs to be confirmed. At any rate, regular exercise is good for nearly everything related to health and emotion.

No: Any regular exercise has health benefits.However,swimming may or may not be a good exercise for asthma affected patients.Unfortunately, the chlorine added to the water can convert to gas form & evaporate from the water surface where you are inhaling air.The gas can/does trigger bronchospasm (attacks) for some.An excess in one local pool sent 3 dozen normal people to the ER with wheezing.

Possibly, but..: Swimming in a chlorine free pool should help but swimming in chlorinated water can actually worsen it.