R3 Seminar Recap: Characterization of PASC and investigation of biomarkers: Insights from the RECOVER adult cohort
RECOVER researchers shared how biomarkers and the RECOVER-Adult Long COVID Research Index can help researchers understand, diagnose, prevent, and treat Long COVID.
During the February 11th RECOVER Research Review (R3) Seminar, Dr. Grace McComsey (Case Western Reserve University) and Dr. Kristine Erlandson (University of Colorado Anschutz Medical Campus) discussed how biomarkers – signs of disease that can be observed and measured – may provide information that will improve researchers’ ability to understand, diagnose, prevent, and treat Long COVID. Dr. McComsey and Dr. Linda Geng (Stanford University) also discussed recent updates to and findings from the RECOVER-Adult Long COVID Research Index.
Watch the R3 recording below or on YouTube
Dr. McComsey highlighted the importance and urgency in identifying Long COVID biomarkers that will help understand, diagnose, prevent, and treat the condition. Without biomarkers, the diagnosis of Long COVID relies on identifying symptoms or clusters of symptoms. However, symptoms can greatly vary case by case. Many symptoms are also common for other illnesses.
Even if people do not show symptoms, Dr. McComsey suggests that biomarkers can help us identify people who have Long COVID. RECOVER researchers are working to understand different types of biomarkers, as likely no one biomarker alone will indicate that someone has Long COVID. To move this research effort forward, Dr. McComsey suggests that researchers should explore how other factors can impact biomarkers such as:
Differences by sex
The varied Long COVID symptoms or clusters of symptoms people may experience
Race and ethnicity
Dr. Erlandson presented findings from a RECOVER research publication which looked for, but did not identify, reliable biomarkers to confirm a past SARS-CoV-2 infection (the virus that causes COVID-19) or likely Long COVID. The study reviewed 25 common clinical laboratory values (or test results). Researchers found differences between study participants who had a prior SARS-CoV-2 infection and participants who did not through:
platelet counts
HbA1c (a blood test that measures blood sugar)
albumin/creatinine ratio (a blood test that measures kidney health)
Although researchers identified differences in test results, they found the clinical relevance of these differences unclear. Dr. Erlandson shares that understanding the causes of Long COVID may require a new biomarker to clearly distinguish a person who has Long COVID but may not have a confirmed prior or current SARS-CoV-2 infection.
Dr. Geng then discussed the 2024 Update of the RECOVER-Adult Long COVID Research Index, which seeks to identify the most distinguishing symptoms of Long COVID. Compared to the research index originally released in 2023, the updated 2024 index includes almost 4,000 additional participants and a total of five symptom clusters. These 5 symptom clusters increased from 4 clusters in the 2023 research index, which further shows the varied Long COVID symptoms people can experience.
Key findings from the updated research index include:
Fatigue and post-exertional malaise are commonly identified across all clusters.
Individuals in cluster 5 were more likely to experience severe or persistent symptoms across multiple body systems and a lower quality of life.
A high proportion of individuals in cluster 5 were not vaccinated for COVID-19 or had a SARS-CoV-2 infection before the Omicron variant began to spread.
While the index is not intended for clinical use and may not capture all possible Long COVID symptoms, Dr. Geng highlighted that this 2024 update helps RECOVER researchers classify symptomatic Long COVID and its different subtypes. The index improves researchers’ ability to identify patterns in how Long COVID symptoms may present. She also noted that our understanding of Long COVID will continue to evolve, and the research index will need to be refined as we learn more about the condition.
Dr. McComsey emphasized that the research highlighted during the seminar is the starting point to understand Long COVID biomarkers, and that more research is needed. She notes, “We have in RECOVER a lot of samples, a lot of data, but more importantly, [we have] a lot of passionate scientists and community members who are working [with us] hand in hand. We are committed to finding biomarkers and mechanistic pathways that will treat Long COVID.”
To find recordings and transcripts of more R3 seminars, visit the RECOVER YouTube channel and the R3 webpage.