Question

I see that ME and Long Covid are now sometimes being referred to as being a post-acute infection syndrome. Why is this?

And following on from this question, one important action in the generally disappointing research section of the DHSC Delivery Plan is to fund research into post-acute infection syndromes. So is this good or bad news for people with ME if we are going to be lumped in together with all kinds of post-infective conditions?

Answer

As you indicate, there are a considerable number of long-lasting illnesses that begin after someone fails to properly recover from an infection – often a viral infection. Two of the well-known examples are ME/CFS and Long Covid. Other good examples of infections that can cause a PAIS include Brucellosis, Lyme disease, polio (post-polio syndrome) and Q fever. These syndromes can also follow tropical infections such as chikungunya, dengue fever and Ebola virus infection – helping to disprove that these post-infection syndromes are just diseases of the affluent people living in developed countries.

In addition to symptoms such as fatigue, cognitive dysfunction, sleep disturbance and pain that are commonly found in most or all of these syndromes. Researchers have identified a number of potential causative factors that are often present. These include:

• Neuroinflammation – meaning inflammation of nervous system tissues: Possibly as a result of continuing low-level activation of the body’s immune system.
• Mitochondrial dysfunction: A reduced capacity to generate adenosine triphosphate (ATP), the primary energy source for cells, leading to a decrease in physical and mental performance.
• Immune dysfunction: This can include persistent inflammation, reactivation of latent viruses (such as Epstein-Barr virus), and the presence of autoantibodies – which attack the body’s tissues.
• Endothelial dysfunction: Disruption of blood flow and the blood-brain barrier, contributing to cognitive and cardiovascular symptoms.
• Gut dysbiosis: An imbalance in the gut microbiome that may perpetuate generalised inflammation.
• Oxidative stress: An imbalance between the production of free radicals and the body's ability to neutralize them, leading to cellular damage and disease.

So the simple answer to your second question is yes, there are likely to be advantages for people with ME/CFS by allocating a part of the research pot to research that involves ME/CFS as well as Long Covid, and possibly some of the other post-infection syndromes. Given the huge amount of money that has gone to Long Covid research over the past five years, along with research interest from researchers who had never been interested in these conditions before, this is likely to be good news for people with ME/CFS – providing research that specifically targets ME/CFS also carries on.

• Dr Shepherd took part in an American podcast with Dr Ken Friedman in August where they discussed PAIS and the overlaps between Long Covid and ME/CFS