Long Covid Newsletter
Issue #39June 1, 20267 studies
Long COVID patients show hyperactive blood clotting 15 months after hospital discharge
New research this week reveals how long COVID affects everything from blood clotting to brain function, while also showing which treatments might actually help—and which might make things worse.
🩸 Blood Still Clotting Abnormally More Than a Year After COVID
- 93 COVID survivors who had acute lung injury showed persistent blood clotting problems 15 months after leaving the hospital
- 24% developed long COVID, and those patients had significantly higher fibrinogen levels—a protein that makes blood clot more easily
- The hypercoagulation was specifically linked to post-exertional malaise (43% of patients) and fatigue (27%), but not brain fog
Why it matters: This suggests that some long COVID symptoms might stem from ongoing blood clotting issues that could potentially be treated with targeted therapies.
Key Findings
🧠 Autoantibodies May Drive Neurological Long COVID Symptoms
- Researchers found that long COVID patients develop autoantibodies that attack their own nervous system proteins
- When they injected these antibodies into mice, the animals developed fatigue-like behavior, balance problems, pain sensitivity, and nerve damage—mirroring human long COVID symptoms
- The antibodies specifically reacted with brain regions like the locus coeruleus and thalamus, plus peripheral nerves
💡 This provides the first direct evidence that autoantibodies may actually cause long COVID symptoms, not just correlate with them.
📊 Current Surveillance Misses Most Long COVID Cases
- Analysis of 457,950 COVID patients across 58 US hospitals found 16.28% developed long COVID—more than double what diagnostic codes capture (<7%)
- 89.31% of long COVID patients developed chronic conditions requiring ongoing medical care
- Cases kept increasing through mid-2024 rather than declining, indicating an accumulating health burden
💡 Healthcare systems may be dramatically underestimating the true scope of long COVID's impact on chronic disease.
💊 Steroid Treatment During COVID Linked to More Long COVID
- 1,044 hospitalized COVID patients in Japan were tracked for 12 months after discharge
- Those who received corticosteroids during acute COVID had 71% higher odds of developing long COVID symptoms
- The association was strongest in patients who didn't require oxygen therapy, and muscle weakness was specifically linked to steroid use
💡 Steroids may help during acute COVID but could increase the risk of persistent symptoms afterward.
🏃 Exercise Helps Severe COVID Survivors Recover Function
- 30 severe COVID survivors completed 6 weeks of multicomponent exercise training (3 times per week, 40-60 minutes)
- All participants showed significant improvements in quality of life, physical activity levels, respiratory muscle strength, and functional tests
- Adding inspiratory muscle training to regular exercise provided additional benefits for physical activity levels
💡 Structured exercise programs may be key to helping severe COVID survivors regain physical function and quality of life.
👁️ Eye Tracking Reveals Cognitive Changes in Long COVID
- 526 participants (397 long COVID patients, 129 controls) completed stereoscopic tasks while researchers tracked their pupil responses
- Long COVID patients showed significantly reduced pupillary activity indices at all difficulty levels
- The changes may reflect altered cognitive load processing and autonomic nervous system regulation
💡 Pupil responses during cognitive tasks could provide an objective way to measure long COVID's impact on brain function.
🌍 Omicron Causes Less Severe Long COVID Than Earlier Variants
- 115,737 people in Norway completed questionnaires 3-35 months after COVID infection between 2020-2023
- Long COVID symptoms were less common at the end of 2022 compared to 2020
- Infections during the Omicron period were associated with lower symptom prevalence than infections with earlier variants
💡 The evolution of COVID variants may be reducing the severity and frequency of long-term symptoms.
Implications
This week's research reveals long COVID as a complex condition involving blood clotting abnormalities, autoimmune attacks on the nervous system, and measurable changes in brain function. While newer variants may cause milder long COVID, current healthcare surveillance is missing most cases, and some treatments like steroids might paradoxically increase long-term risks.
Studies in this issue
Primary sources used for this newsletter.
- Subtle Blood Clotting Changes Linked to Long-Term Physical Symptoms in COVID-19 Lung Injury Survivorsmain storyJournal of intensive care medicine2026-05-27PMID 42200676
- Exercise Rehabilitation for Severe COVID-19 Survivors with Long COVID: A Small Randomized Studykey findingMedical sciences (Basel, Switzerland)2026-05-27PMID 42201014
- Changes in Pupil Response During Tasks in Post-COVID Syndromekey findingMedical sciences (Basel, Switzerland)2026-05-27PMID 42201061
- Ongoing Long COVID Symptoms and Monitoring Gaps at 58 US Hospitalskey findingJAMA network open2026-05-27PMID 42201733
- Autoantibodies may be linked to neurological symptoms in long COVIDkey findingCell2026-05-28PMID 42208499
- Link between steroid treatment during acute COVID-19 and Long COVID symptomskey findingRespiratory medicine2026-05-26PMID 42190841
- Long COVID symptoms before and up to 3 years after COVID-19 infection in Norway, comparing different pandemic periods and virus variantskey findingInternational journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases2026-05-28PMID 42208931
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