Researchers at Johns Hopkins have published the findings of a multi-center, randomized trial that evaluated if COVID-19 convalescent plasma limits long COVID odds. The study results examined the association “between early COVID-19 convalescent plasma (CCP) treatment, cytokine levels, and post-COVID conditions (PCCs).” According to the University of Minnesota’s Center for Infectious Disease Research and Policy, “[c]ytokines and chemokines are signaling proteins that cells secrete in response to an infection. They trigger immune reactions such as inflammation, which may be excessive or unchecked in COVID-19, potentially leading to long COVID, also called [PCC].”
The published data appears in mBio, the peer-reviewed journal of the American Society for Microbiology, as the authors measured “21 different human cytokine and chemokine analytes” in 882 participants at “baseline, day 14, and day 90.” Specifically, the authors COVID-19 studied whether convalescent plasma limits long COVID odds.
The study’s primary outcome was, “PCC, which was defined as the presence of any self-reported symptom (cough, fatigue, shortness of breath, headache, neurologic changes, loss of taste, loss of smell, nausea, vomiting, diarrhea, runny/stuffy nose, myalgias, sore throat, chills, fever, or skin manifestations) at the 90-day visit.” The researchers also noted that, “IL-1RA, IL-6, IL-8, IL-15, and MCP-1 were elevated at baseline among those with PCC compared to participants who did not develop PCC.”
The authors explained that, “median age of the 882 subjects was 43 years, with 299 (33.9 percent) ≥50 years. Five hundred six (57.4 percent) female and 116 Black (13.2 percent) participants were included.” The study found that, “older age, female sex, and baseline elevated IL-6 were associated with PCC…[T]here was a trend for early treatment with CCP to have the lowest odds of PCC (AOR = 0.75 [0.46, 1.23]) compared to early administration of control plasma. [W]hen evaluating only those who received CCP, there was a statistically significant decreased odds of PCC in those who were treated within five days of symptom onset (AOR = 0.60 [0.38, 0.95]) compared to those who received late CCP treatment. There was no statistically significant interaction between CCP treatment and IL-6.”
The researchers stated that their findings suggest that treatment with convalescent plasma limits long COVID potentially. “This study is among the first to show elevation of IL-6 at infection was associated with PCC and that early treatment with CCP for COVID-19 trended toward a lower odds of PCC. Notably, greater levels of IL-6 at baseline were associated with the presence of persistent symptoms at day 90, while early treatment with CCP was associated with lower odds of PCC.”
They acknowledged several limitations of their research including that, “this study was done early in the pandemic when relatively few participants were fully vaccinated. Results may differ among participants who have immunity from prior infection or vaccination.”
Citation: Gebo, K., Heath, S., Fukuta, Y. et al. “Early antibody treatment, inflammation, and risk of post-COVID conditions.” mBio. 2023.