Why is it so hard to study long Covid? - Vox.com

Why is it so hard to study long Covid?  Vox.comHealth experts release study surrounding "Long COVID" as many are impacted  CBS ColoradoLong COVID: The Top 2 Neuropsychiatric Symptoms  PsyBlogLong Covid linked to increased risk of death and other cardiovascular issues in new study  New York Daily NewsStudy identifies painful Covid symptom that can present six months after ‘mild’ infection  ExpressView Full Coverage on Google News