Key points:
- Researchers followed patients who survived severe COVID-19 and divided them into “early resolvers” and “late resolvers” based on their lung health following infection.
- Late resolvers, who continued to suffer lung problems after six months, had fewer monocytes compared with both patients who had recovered and healthy control subjects.
- Doctors may be able to use a simple blood test to identify monocyte levels and predict if patients with COVID-19 are likely to have long-haul lung problems.
Researchers discovered a possible way to predict which patients with severe COVID-19 are likely to recover and which are likely to suffer long-haul lung problems. These findings, published in Frontiers in Immunology, may help doctors personalize treatments for individual patients.
Many patients who suffer persistent symptoms after recovery also develop lung scarring. This scarring can emerge early on in their hospitalization or within six months of initial illness. To understand why scarring occurs, researchers followed 16 UVA Health patients who survived severe COVID-19.
At a 6-month follow-up, the research team found that patients could be divided into two groups. One group—“early resolvers”—had their lung health improve, while the other group—“late resolvers”continued to suffer lung problems and experienced pulmonary fibrosis. Late resolvers also had significantly fewer circulating monocytes compared to both patients who recovered and healthy control subjects. This decrease in monocytes was related to the severity of patient’s ongoing symptoms.
Researchers also examined if severe COVID-19 could cause progressive lung scarring as in idiopathic pulmonary fibrosis. Severe COVID-19 and idiopathic pulmonary fibrosis had different effects on immune cells, indicating that the underlying causes were distinct even for patients with the most persistent long-haul COVID-19 symptoms.
The results from this pilot point to the critical need for larger, multi-center studies. The team is hopeful that expanding on their discovery will allow doctors to use a simple blood test to identify monocyte levels and predict if patients are likely to become long-haulers. Understanding the risk for long-haul lung problems can help doctors personalize treatment, improve care, and guide patients to recovery.
“We are excited to find that people with long-haul COVID have an immune system that is totally different from people who have lung scarring that doesn’t stop,” said Catherine Bonham of University of Virginia. “This offers hope that even patients with the worst COVID do not have progressive scarring of the lung that leads to death.”