Defining Post-COVID Symptoms (Post-Acute COVID, Long COVID, Persistent Post-COVID): An Integrative Classification

The pandemic of the coronavirus disease 2019 (COVID-19) has provoked a second pandemic, the long-haulers, i.e., individuals presenting with post-COVID symptoms. We propose that to determine the presence of post-COVID symptoms, symptoms should appear after the diagnosis of SARS-CoV-2 infection; however, this situation has some problems due to the fact that not all people infected by SARS-CoV-2 receive such diagnosis. Based on relapsing/remitting nature of post-COVID symptoms, the following integrative classification is proposed: potentially infection related-symptoms (up to 4-5 weeks), acute post-COVID symptoms (from week 5 to week 12), long post-COVID symptoms (from week 12 to week 24), and persistent post-COVID symptoms (lasting more than 24 weeks). The most important topic is to establish the time reference points. The classification also integrates predisposing intrinsic and extrinsic factors and hospitalization data which could promote post-COVID symptoms. The plethora of symptoms affecting multiple systems exhibited by long-haulers suggests the presence of different underlying mechanisms.

Automated summary

The symptoms of long-haulers of COVID-19 can be classified into potentially infection-related, acute post-COVID, long post-COVID, and persistent post-COVID stages. Establishing time reference points is crucial, while the plethora of symptoms affecting multiple systems suggests the presence of different underlying mechanisms.