A study of 40,537 people found key immune cells that fight infections were still below earlier levels up to 20 months after the major COVID wave. In people with heart and blood vessel disease, some of these cells were about 70% lower than earlier levels. The paper looked at lymphocytes, which are white blood cells that help fight infection.

T cells help organize the response and can kill infected cells.
B cells make antibodies.
NK cells are fast-acting white blood cells.
CD4 and CD8 are two main T-cell groups.

Pieces of SARS-CoV-2 proteins were found in tiny blood particles in many people with long COVID, even about 17 months after infection. This may point to a measurable biological signal, not just symptoms. Breakdown in simple language 🧵 Those tiny particles are extracellular vesicles (EVs). EVs are small packages released by cells into the blood that can carry proteins and other material.

A study found a small set of molecules in blood that can separate people with Long COVID from recovered patients 1 year after severe infection.

Using machine learning on metabolomics data, researchers identified 9 molecules linked to energy problems in the body. The study looked at people who were very sick with COVID and needed ICU care.

About 1 year after leaving hospital, researchers compared two groups:

21 people with ongoing Long COVID symptoms
21 people who had recovered.

New research suggests antibodies from people with ME/CFS and Long COVID may directly change how cells handle energy and inflammation.

The study found these antibodies may fragment mitochondria and alter immune signals. Researchers wanted to test a simple question.

Do antibodies from patients change how healthy human cells behave?

Antibodies are proteins made by the immune system. Their normal job is to attach to things like viruses or bacteria.

CAR-T is a treatment that takes your own immune cells, reprograms them to attack a specific target, and puts them back into your body. It is already used in some blood cancers.

In this thread, I will explain how it works and how it could potentially relate to long COVID and ME/CFS. Your immune system has T cells. These are cells that can recognize and kill other cells that look dangerous.

In CAR-T therapy, doctors collect some of your T cells from your blood.

Many patients are told they have Functional Neurological Disorder (FND). This includes people with long COVID, ME/CFS, and many others. The core issue is that FND is built on flawed logic. When you break down the criteria, it often becomes a diagnosis of “we don’t understand.” The first pillar is “no structural problem found.” In plain terms, this usually means routine tests did not show major damage. But routine tests are limited. A normal MRI does not prove the brain is healthy. It mainly rules out big, obvious problems.

A mitochondrial drug is being tested for long COVID fatigue with post exertional malaise (PEM). What it does, and what the prior trials found 🧵

clinicaltrials.gov/study/NCT07298… The drug is sonlicromanol, also called KH176. It was built for inherited mitochondrial diseases.

It is related to a vitamin E like antioxidant (Trolox) and is designed to reach many tissues, including the brain.

ME/CFS blood antibodies may shift how mitochondria look and how energy is used in human blood vessel lining cells.

The effect looked more specific to ME/CFS groups than to MS, and the active part seemed to be the Fab “binding” side of IgG. They purified IgG (a common antibody in blood) from serum of 4 groups:

post infectious ME/CFS
post COVID ME/CFS
MS
healthy controls

Samples were collected 2020 to 2023.

New study:

People with ME/CFS and Long COVID show a clear drop in how their bodies make energy after exertion.

This drop appears on repeat testing, and not just from being unfit. The study is a January 2026 preprint

It tested people with ME/CFS, Long COVID, and healthy controls.

A new paper suggests extreme, long exercise may sometimes link to worse memory and “brain fog”, via tiny particles released from stressed muscle mitochondria that can reach the brain.

Simple breakdown and then I’ll dig into how this could relate to PEM. The paper combines big human data, mouse experiments, and lab work to propose a muscle-to-brain pathway.

Human activity data is observational, so it cannot prove cause, but it helped them define what “excessive” might look like.

Many diseases were once called “psychological” or “all in the mind”.

Again and again, biology later proved otherwise.

This thread shows clear cases where medicine got it wrong, then changed its mind once real mechanisms were found. This pattern repeats:

Patients report physical symptoms.

Doctors cannot measure them yet.

The condition is labelled psychogenic.

Years later, new tools show a biological cause.

Brain scans in ME/CFS and Long COVID have found changes in glutamate and GABA, the chemicals that control brain activity.

Multiple studies now suggest disrupted excitation and inhibition may be linked to brain fog, fatigue, and sensory symptoms. Let’s breakdown in simple terms. Glutamate is a main brain signal that increases nerve cell activity.

GABA is a main signal that reduces activity.

Some researchers think symptoms in ME/CFS or long COVID could involve this balance, but evidence is early.

Scientists just mapped tiny veins across the entire living human brain in under 7 minutes using ultra-high resolution MRI.

Previously this kind of detailed view was mainly built from postmortem (after death) methods.

Here’s what they did and why it matters. The study used a very strong MRI scanner called 7-Tesla.

Higher strength means clearer images.

This allowed them to see very small brain veins that are normally invisible in standard hospital scans.

Breakdown of our Health Rising interview: we’re building one of the biggest Long COVID + ME/CFS biology datasets yet, using a blood test that reads ~20,000 gene activity signals plus a 350-question symptom map. The aim is to find subgroups and speed up treatments that may actually fit. We were recently interviewed by Cort at Health Rising about Amatica Health:

Our mission to help solve ME/CFS + Long COVID, how we’re doing it (big patient data + deep biology), what we’ve achieved so far, and what we think the field is missing.

New research on ME/CFS finds unusual cell signals after exercise.

Tiny packages released by cells (extracellular vesicles) show problems with energy production, an overactive immune system, and cell stress. Let’s break it down in simple terms. ME/CFS patients often experience “post-exertional malaise” (PEM) - a severe worsening of symptoms after activity.

Even light exercise can leave them exhausted, in pain, or cognitively impaired for days.

The biological cause of PEM has been unclear.

New analysis suggests treating COVID-19 right at its entry point (nose & throat) can slow or stop the virus early.

Using simple nasal sprays or gargles (like iodine solution or salt water) early on might lower the risk of severe illness. C19Early is a site run by independent researchers that compiles COVID-19 treatment studies.

This page focuses on nose/throat treatments, aiming to inform both doctors and the public about early interventions to stop the virus at its entry point.

For the first time, scientists have reversed advanced Alzheimer’s disease in mice - fully restoring memory and repairing brain damage by targeting the brain’s energy supply. Alzheimer’s has long been seen as irreversible, so treatments only aimed to slow it.

This study shows that even late-stage Alzheimer’s might be reversible by fixing the brain’s energy balance

New research finds ME/CFS symptoms cluster into 4 distinct groups.

Each group is linked to a different body system: the brain, the autonomic nervous system, the gut, or the immune system What is ME/CFS?

It stands for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

It’s a serious long-term illness, often triggered by a viral infection, that causes extreme fatigue and a mix of other symptoms all over the body.

Lab-grown mini muscles showed that blood from people with chronic fatigue syndrome (ME/CFS) and Long COVID can directly weaken and damage muscle cells.

The muscles first tried to adapt their energy use, then became fragile and lost strength. Why do this study?

ME/CFS and Long COVID cause extreme fatigue and muscle weakness, but the reasons are unclear. Scientists wanted to see if something in patients’ blood affects muscles.

They built a new lab model to test this idea.

New research finds people with ME/CFS have a striking deficiency in vasopressin - a hormone that helps the body retain water.

This could explain common symptoms like constant thirst and dizziness upon standing.

Let's break down the findings. ME/CFS involves orthostatic intolerance (trouble staying upright, often causing dizziness or a fast heartbeat upon standing). Many also report extreme thirst and frequent urination, hinting at a water balance problem.

2025 brought big new clues about Long COVID and ME/CFS:

Genes tied to risk, immune and clotting changes, PEM findings, possible blood tests, and brain changes.

Here is an end of year round up in plain language. Long COVID genetics

A huge study of thousands of people found specific spots in our DNA that raise the risk of long COVID, many in immune and lung related genes. This confirms a clear biological driver.