Thread by @dgurdasani1

Ok, time to do a thread on long COVID. Long COVID is a *real* multi-system syndrome that occurs in those infected (far more common than in uninfected controls)- predominantly impacting the young. Let's do a deep delve into this syndrome that some in JCVI are in denial about! 🧵

Some stats first - there are several studies that now put the overall incidence of long COVID as between 10-50% of those infected, depending on symptoms studied & cohorts studied. Let's look at some of these.

First, ONS data & REACT-1 data- these are some of the most robust data on long COVID. Why?
-They include infections based on PCR tests through random nationally representative surveys of thousands of people
-ONS data was based on 313,216 samples, REACT-1 on 508,707 people

The ONS data compares symptoms post-infection among those infected with control groups of those confirmed not to have infection. Persisting symptoms were *8x* more common among those testing positive with PCRs compared to those who were negative.

This strongly challenges the rhetoric by some about 'floating numerators' & that this is 'background symptoms' in the population. The ONS survey showed very clearly that 13.7% of those infected (1 in 8) developed long-term symptoms > 12 wks compared to <2% controls

'But it doesn't affect old people'... it absolutely does! The majority of those affected are <50 yrs. And it affects children. Between 10-13% of children have symptoms for 5 wks or more, and 7-8% of children had symptoms for *12 wks or more* compared with <2% of controls.

'But it's just mild symptoms that don't matter, and most people only have 1 symptom'
Unfortunately, there's a plethora of symptoms, and many of them are very common, so many people present with a combination of symptoms. The ONS only examined 21- there are 100s of symptoms.

This means the ONS estimate may be underestimating the prevalence of long COVID considerably. Also these symptoms are not mild. Of the ~1 million people affected, 2/3rds said it impacted their day to day activity. And 400,000 have had persistent symptoms for more than a year.

These 400,000 sadly include 9000 children who have been affected for more than a year. This isn't a mild syndrome, or a short one for thousands of our young- who've been impacted due to policies where they were forced to go into unsafe environments without adequate mitigation.

So what does the REACT-1 study, which examined more than half a million people show? This study is limited to >=18 yr olds in England. This examined 29 symptoms, and showed 1 in 3 people with COVID-19 had symptoms lasting more than 12 weeks. This included young adults.

For most affected, this wasn't a single symptom. It was a combination of many symptoms. e.g. 20% of those infected reported 3 or more symptoms and 17% reported 4 or more symptoms at 12 weeks. Note that there isn't much drop off in prevalence of symptoms after 12 wks

So if symptoms persist for 12 weeks as they do in 1 in 3 people as per the REACT-1 study, they tend to persist for much longer (up to 22 weeks or more). Also 1/3rd of those with one symptom persisting said it impacted their day to day lives- that's just above 10% of cases.

Risk factors that increased risk included being a woman, increasing age, smoking, and low income, deprivation, and severe acute infection requiring hospitalisation.

That this is a disease that affects disadvantaged & women more might explain why many are happy to dismiss it.

Another study from Norway showed persistent symptoms at six months were even more common, where over half had persistent symptoms at 6 months (including children). These were people self-isolating at home so not severe illness needing hospitalisation.
nature.com/articles/s4159…

So, to summarise, long COVID is common - even in young people with mild infection - who don't have to go into hospital. And it also affects children, and is usually multiple symptoms, that in many affect day to day lives. Let's look at other data now.

The cognitive symptoms (brain fog, memory loss, difficulty concentrating, sleep disturbances) tend to become prominent later in long COVID, & also last longer. These are worrying also because there are now studies showing the virus affects the brain, even in younger people.

I've summarised some of the evidence here. There is strong evidence now that even those with mild infection can have long-term structural brain changes, including thinning of grey matter is specific brain areas related to smell, taste, memory & emotion

https://twitter.com/dgurdasani1/status/1406726553690595332?s=20

Neuro-psychiatric disease is common post-COVID even among those not hospitalised with severe infection. COVID-19 also appears to be associated with increased risk of strokes, and other neurological conditions at 6 months post infection:

https://twitter.com/dgurdasani1/status/1379721348285673472?s=20

What else do we know about what COVID-19 does to our immune system?
There's good evidence now that acute infection with COVID-19 leads to a plethora of auto-antibodies against many tissues in our body. We don't know the impact of these fully yet.

nature.com/articles/s4158…

We also know that acute infection has impact on many organ systems in those affected with severe infection, including among young people. A recent study of >70,000 hospitalised patients showed that *half* had at least one organ system affected- lung/kidney/heart/brain/gut

The risk of organ dysfunction was 38·9% in those aged 19–49 years - clearly impacting a very high proportion of young people as well.
thelancet.com/journals/lance…

Another large study among those hospitalised in England showed that 1 in 3 were re-admitted after discharge, and 1 in 10 died within 5-6 months. This was 4-8 times higher than in the control hospitalised group studied - matched on many factors.
bmj.com/content/372/bm…

Organ disfunction was common, and far more prevalent in those hospitalised with COVID-19 than in the control group. And more associated with COVID-19 in under 70s compared to over 70s.

There are also many studies that suggest SARS-CoV-2 impacts our immune system- including T cell ageing & dysregulation of immune responses following infection. There is also evidence of virus persistence in some tissues. I'm not an immunologist- pl follow @fitterhappierAJ on this

I hope this will go a way to convince those who still aren't that long COVID is a biologically complex syndrome, that is common, and concerning. It impacts young people, and is often quite functionally severe and debilitating. So let's not minimise this.

yes, we don't fully understand the underlying pathology yet, and this will take time, but all indications are that it is serious - even in children. And very likely affects multiple organ systems, with long-term impacts even on young people.

So there is uncertainty- but this uncertainty doesn't mean we can ignore these very real risks - when all signs are pointing in a very worrying direction. We *must* adopt the precautionary principle & protect our young from this multi-system chronic disease.

There is scientific consensus that this is not just a respiratory disease, but a multi-system one. Here's really good review from Nature medicine on this. So let's not follow ideology. Let's follow the current evidence. All of which is gravely concerning.

nature.com/articles/s4159…

Choosing to expose children to infection rather than vaccinate them, when millions across the world have been safely vaccinated is negligent, and harmful. We are exposing children to a multi-system chronic illness we don't understand & don't know how to treat.

If you are one of the scientists who made this choice, please be honest that this is ideology, and not science. Because the evidence tells us to be very very cautious about exposing children to infection, & that the benefits of vaccines far outweigh harms.

https://twitter.com/CDCDirector/status/1408116464683569157?s=20

And pl follow @Daltmann10 @VirusesImmunity @kamleshkhunti @Dr2NisreenAlwan @trishgreenhalgh for accurate information on this.

I partly wrote this thread so anyone could use it to counter false narratives & unevidenced critique from long COVID deniers. Please feel free to link it to anyone who suggests there isn't strong evidence for long COVID. They can then engage on facts.

Sorry, earlier tweet should have read 'but it doesn't affect *young* people', Yes it does!

Also, want to add that there's amazing patient-led work in this area which looked at 74 symptoms of long COVID, and consistent with many other studies showed that neuro-cognitive symptoms tend to increase and persist over time, which is deeply concerning.

thelancet.com/journals/eclin…

This work was led by @AthenaAkrami and Hannah Davis. Please do follow her, and the many groups who have educated us about this through their lived experience including @LongCovidKids