02/15/2026
Scientists just found a microscopic reason for the exhaustion of long COVID.
Researchers have identified unusual, microscopic structures lurking in the blood of patients that could be driving symptoms like brain fog and chronic fatigue.
These structures are known as microclots. While a typical blood clot might be large enough to cause a stroke, these are tiny, persistent accumulations that are just big enough to block the smallest blood vessels, known as capillaries. This blockage can prevent oxygen from reaching vital tissues and organs. In a recent study, patients with long COVID had a nearly 20 fold increase in these microclots compared to healthy individuals.
But the researchers found something even more unusual. The microclots were physically embedded with neutrophil extracellular traps, or NETs. These are sticky, web like structures made of DNA and enzymes that white blood cells spit out to trap invading pathogens. In a healthy body, NETs appear, do their job, and dissolve. In long COVID patients, they seem to stay stuck, acting like a structural mesh that makes the microclots much harder for the body to break down.
This interaction creates a stubborn, "thromboinflammatory" environment. Because these sticky webs are so distinct, an AI agent was able to identify long COVID blood samples with 91 percent accuracy. This is a massive breakthrough for a condition that has been notoriously difficult to diagnose with standard medical tests.
The discovery suggests that long COVID is not just a lingering malaise, but a measurable physical state involving dysregulated blood chemistry. If scientists can target these NETs and microclots, it may offer a clear path toward treating the underlying cause of the disease rather than just managing the symptoms.
Read the study:
"Circulating Microclots Are Structurally Associated With Neutrophil Extracellular Traps and Their Amounts Are Elevated in Long COVID Patients." Journal of Medical Virology, 2025.
