Question

Are the researchers any further forward in deciding whether microclots play a role in the causation of Long Covid, and possibly ME/CFS? And is there any evidence that blood-thinning drugs, or blood-exchange procedures such as apheresis, are effective forms of treatment for either condition?

Answer

As you are probably aware, a research group in South Africa published some interesting results in Nature Medicine back in 2024 which suggest that there are tiny particles in blood vessels of people with Long Covid that have been named microclots. This has led to a hypothesis that these microclots are causing an obstruction in tiny blood vessels called capillaries and reducing the supply of oxygen to the tissues.

Since this hypothesis was published, it has attracted a lot of interest and quite a lot of criticism about various aspects of the way in which this research has been conducted – in particular the fact that these microclots are not like normal blood clots and are made of substances called amyloid and fibrinogen.

And, with no other research group publishing results which support the presence of these microclots in either Long Covid or ME/CFS, medical opinion remains very sceptical.

If these microclots are not the same as normal blood clots, then it’s highly unlikely that anticoagulant drugs (aka blood thinners) are going to be a useful form of treatment. Anticoagulant drugs can also have very serious side-effects. So their use in ME/CFS is not recommended.

• Reference – critical review of the current evidence relating to microclots: Hunt B.J., Kuehn R., Fox T., Carson A., Scandrett K., Davey Smith G., et al. Challenging the current hypothesis that thrombosis is responsible for the post-COVID-19 condition. Res Pract Thromb Haemost. 2024;8 doi: 10.1016/j.rpth.2024.102442.

SEE ALSO: Micro-clots, Treatment: Apheresis