Researchers have identified key differences in the blood of individuals with long Covid compared to those who have recovered from COVID-19, paving the way for potential diagnostic tests and insights into the condition. The study found irregularities in the activity of immune system cells called T cells and B cells, as well as significantly lower levels of the hormone cortisol in long Covid patients, which could explain their fatigue. Additionally, dormant viruses like Epstein-Barr were found to become active again in long Covid patients, though the role they play in symptoms remains unclear. Long Covid affects 1 in 13 U.S. adults.

A small study suggests that taking creatine supplements for six months may significantly improve clinical features of post– COVID-19 fatigue syndrome (PVFS or long COVID). This study is among the first to explore the potential benefits of creatine in long COVID patients and found that it led to a significant reduction in fatigue and improvements in various long COVID-related symptoms. However, experts caution that the study's small sample size and the limited duration of recent COVID infections in participants make the results preliminary, and further research is needed to confirm these findings.

A new study suggests that the risk of "long COVID" may have been exaggerated due to flawed research methodologies. The study highlights issues with the definitions and methodologies used in research on long COVID, including the lack of appropriate comparison groups and poorly conducted studies that may have contributed to an overestimation of the risk. The researchers argue that better case definitions and more stringent criteria are needed to accurately assess the risk of long COVID and that the term "long COVID" should be replaced with different terms for specific after- effects. They also emphasize the importance of improving research standards to avoid misdiagnosis and inappropriate treatment.