The discussion revolves around the potential for undetected long COVID cases characterized by subtle symptoms that may be overlooked. Participants note that long COVID is defined by the persistence of negative symptoms following an initial COVID-19 infection, and typically manifests with clear symptoms. However, there is acknowledgment that some individuals may experience long COVID after being asymptomatic during their initial infection, later developing new health issues. The conversation draws parallels to flu cases, where many infections go unnoticed due to mild or absent symptoms, suggesting that similar patterns could exist with long COVID. The possibility of mild symptoms, such as a slight loss of smell, going undiagnosed is raised, along with the idea that these symptoms could be mistaken for normal aging or unrelated health issues. Overall, the thread highlights the need for further research into the spectrum of long COVID symptoms and the potential for subtle cases to be recognized.