I searched for flu. Couldn’t find much, but generally you would expect a transient effect from fever then a rebound 6-8 weeks out. One well designed study in bo

I searched for flu. Couldn’t find much, but generally you would expect a transient effect from fever then a rebound 6-8 weeks out. One well designed study in boars found a total rebound after a decline, and a study in a single human febrile patient found the same. And no, you wouldn’t expect large fluctuations in healthy people. The longer term reduced outlook seems suggestive of tissue damage. Boar study. They had frequent sperm tests: https://www.aasv.org/shap/issues/v25n6/v25n6p303 https://www.aasv.org/shap/issues/v25n6/v25n6p303 However, the three month followup was weak. Only 5 out of the 30 subjects. Also, my prior comment was wrong, possible sperm effects can last up to four months after fever: https://academic.oup.com/qjmed/article/114/4/287/6131797 https://academic.oup.com/qjmed/article/114/4/287/6131797