CD8A and long COVID-19: These factors were found to correlate with the likelihood of developing chronic symptoms and unique immune responses in patients with gastrointestinal post-acute sequelae of SARS-CoV-2 (PASC), including specific dynamics of SARS-CoV-2-specific and cytomegalovirus (CMV)-specific CD8+ T-cells during recovery, highlighting the importance of early detection and personalized vaccination strategies [73].