A common idea indulged in by the general public is that some serious disorders, such as smallpox and typhoid, when recovered from leave the patient in an improved condition of health. To a certain extent this is based on fact; some diseases leave the patient immune and some disorders, that have but a slightly deleterious effect on the system in general, make the patient at least feel better, if only by contrast, when they are over with. Seasickness is notably one of these with a large proportion of its victims. Again, many people live under hygienic conditions only when they are sick; and rather severe organic lesions might possibly be compensated for by the general benefit due to the enforced abstinence from insanitary habits and modes of living.
“HEALTH-PRODUCING DISEASES”. JAMA. 2008;300(18):2191. doi:10.1001/jama.2008.537