COVID WASTEWATER IN EUROPE, a thread 🧵

Covid prevalence is rising fast in England.

Our Covid wave is only just beginning, but other European countries are further along the curve.

In this thread, I take you on a whistlestop tour through Europe to see what’s been happening...
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It’s important to note that Covid waves impact different countries in different ways, depending on many factors, including:

📍length of time since last big wave
📍% of population recently vaccinated
📍mitigation measures taken by government
📍population density

…and many more.
So, with that in mind, let’s take a little tour around Europe:

1. THE NETHERLANDS 🇳🇱

In the Netherlands, they’re currently seeing the highest EVER Covid wastewater signal.

And it’s not just a bit higher than the previous max - it’s a LOT higher!

coronadashboard.government.nl/landelijk/rioo…
Image
2. AUSTRIA 🇦🇹

In Austria, it’s a similar story. They’ve just seen the Covid wastewater signal rocketing to a new record high.

It’s possible that the Austrian wave has just peaked but it’s still too early to be sure - it may just be a little blip.

abwassermonitoring.at/dashboard/
Image
3. GERMANY 🇩🇪

Likewise, in Germany, they’re seeing the viral load of SARS-CoV-2 in wastewater across the country soaring to new record highs with each passing week.

corona-pandemieradar.de/en/sewage
Image
4. BELGIUM 🇧🇪

Belgium are also seeing another big spike according to their Covid wastewater surveillance, albeit not as extreme (yet) as the waves being experienced in the Netherlands, Austria and Germany.

wastewater.sciensano.be/dashboard/covi…
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5. FRANCE 🇫🇷

In France, they are also experiencing a steep & sustained rise in the Covid wastewater signal, soaring to the highest level in well over a year.

H/t @nicolasberrod
Image
6. SWITZERLAND 🇨🇭

I think perhaps you’re starting to see the trend by now.

Another huge spike in the viral load of SARS-CoV-2 in the wastewater signal (purple line) which, in some areas, is the highest it’s EVER been since the start of the pandemic.

sensors-eawag.ch/sars/overview.…
Image
7. LUXEMBOURG 🇱🇺

Since September, there has been a steady and sustained rise in the SARS-CoV-2 viral load in their wastewater surveillance, once again reaching levels that are as high, if not higher, than the previous record high.

list.lu/fileadmin/file…
Image
8. DENMARK 🇩🇰

The concentration of SARS-CoV-2 in Denmark’s wastewater is again at the highest levels they’ve seen in over a year…

en.ssi.dk/covid-19/natio…
Image
9. FINLAND 🇫🇮

Another similar story. Another massive spike in the Covid wastewater signal.

koronatilastot.fi/fi/jatevesi/
Image
10. CANADA 🇨🇦

I know I said this thread was all about Europe, but this trend is not unique to Europe.

Let’s look further afield and see what’s been happening in Ontario, Canada… 👀

Their Covid wastewater signal has been rising & rising too.

publichealthontario.ca/en/Data-and-An…
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11. USA 🇺🇸

The USA are also seeing signs of a big incoming wave.

biobot.io/data/
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11. USA 🇺🇸 (continued)

@michael_hoerger has been keeping a close eye on the data and predicts that this has the potential to be the 2nd largest COVID surge of all-time in the U.S.

His thread 🧵 below is well worth a read.
Image
12. ENGLAND 🏴󠁧󠁢󠁥󠁮󠁧󠁿

Now you might be wondering what the England wastewater surveillance data looks like…

Well, I’d love to be able to tell you, but sadly England’s wastewater surveillance was axed nearly two years ago, back in March 2022. Image
13. SCOTLAND 🏴󠁧󠁢󠁳󠁣󠁴󠁿

Meanwhile, Scotland have continued to monitor their Covid wastewater signal since 2020.

There was a fairly big double spike towards the end of the summer in August/September. The signal then dropped but has just started to rise again.

scotland.shinyapps.io/phs-respirator…
Image
14. WALES 🏴󠁧󠁢󠁷󠁬󠁳󠁿

Wales recently restarted their wastewater surveillance after a 4 month hiatus when their budget was suddenly axed back in August.

The first report since surveillance restarted has just been published. Image
15. IRELAND 🇮🇪

Ireland also keep close tabs on the Covid viral load in their wastewater.

There’s not any sign of an uplift in their signal just yet.

hpsc.ie/a-z/nationalwa…
Image
So that concludes our whistlestop tour of the Covid wastewater surveillance in Europe (& beyond).

Two key questions arise from my research:

1️⃣ Given that practically every developed nation in the world is conducting Covid wastewater surveillance, why did England stop theirs? Image
As explained in this briefing note for SAGE back in Nov 2020, “wastewater surveillance is a reliable, timely & cost-effective method” of keeping track of Covid prevalence in the community.

So why was the budget for wastewater monitoring axed in England?

assets.publishing.service.gov.uk/media/5fc8d6a2…
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A recent Freedom of Information request revealed that the cost for Wales to resume their wastewater programme was just £621k.

This is a tiny cost in the greater scheme of things, especially when compared to the £billions written off in the PPE scandal.

llyw.cymru/sites/default/…
Image
2️⃣ My second question is, given the huge surges in Covid prevalence across Europe, when are our government going to take action to reduce transmission here?

The WHO, BMA & RCN have called for improved infection control in health facilities - this would be a good place to start.
Millions of Covid vaccine doses have been stockpiled for a potential “surge” campaign this Winter.

Perhaps now would be a good time to release those vaccine doses to protect people in the coming weeks, rather than just leaving them until they expire & need to be destroyed?
Image
Perhaps the gov could also consider bringing back free Covid tests.

In the US 🇺🇸, free Covid tests can be ordered by all households and are sent out by mail:



Here in England 🏴󠁧󠁢󠁥󠁮󠁧󠁿, tests are no longer free for most people. A pack of 6 tests costs ~£10. axios.com/2023/09/20/cov…
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Another thing on my wishlist would be for some decent public health messaging, advising people in England to wear high quality masks (FFP2/3) in public indoor spaces and crowded places…

…like this recent public health campaign from New York. 👇🏻
There will be a huge amount of inter-generational mixing taking place over the next few days, so a public health message reminding people of the importance of VENTILATION could also make a huge difference right now.

Perhaps they could even re-release this video from 2 years ago?
Schools have broken up for the Christmas holidays now - but, by the time they return in a few weeks, Covid prevalence will be almost certainly be far higher.

We desperately need mitigation measures to reduce transmission - especially via improved ventilation & air filtration.

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More from @_CatintheHat

Mar 10
In 2023, the British Council for Offices (BCO) updated the ventilation guidance for offices:

💨 The *minimum* recommended ventilation rate was increased from 12 to 14 litres of outdoor air per sec per person.

Now guess what the ventilation rate is in a typical UK classroom…❓ Image
Since 2022, the Schools Air quality Monitoring for Health & Education (SAMHE) project has monitored indoor air quality in hundreds of schools across the UK.

Shockingly, their data revealed that the ventilation rate in a typical UK classroom is just 5.3 litres per sec per person. Image
Worse still, the data shows the average ventilation rate plummets to just 3.8 litres per sec per person in colder weather.

Now compare this to the MINIMUM recommended ventilation rate for offices of 14 litres per sec per person.

Schools are achieving just a fraction of this! Image
Read 18 tweets
Feb 22
FROM THE OLYMPICS TO NASA, WEARING MASKS IS BACK - EXCEPT IN HEALTHCARE

Brilliant article on how masking is increasingly popular with Olympic athletes, actors & astronauts wanting to avoid illness…

…but sadly, in hospitals, masking is rare & those who do are often gaslit.

🧵 Image
Here’s a link to the online version of this article by the brilliant Tess Finch Lees:
independent.ie/opinion/commen…
The link above is paywalled so here’s an archived link where you can read it for free:


(Please do also click the first link as well though to increase traffic & help persuade editors to publish more Covid stories like this).archive.ph/sfP52
Read 18 tweets
Feb 20
🏴󠁧󠁢󠁳󠁣󠁴󠁿 Something unusual & concerning in Scotland’s Covid data in the last few weeks.

There’s been a sharp rise in the proportion of hospitalised Covid cases which are children.

Currently over half of all Covid hospitalisations in Scotland are kids aged 0-14 years.

(h/t @gwladwr) Image
The data also shows that, since January, Covid incidence rates for these younger age groups have been going into the ‘high’ (dark blue) and ‘very high’ (purple) classifications, particularly the 1-4 years age group. Image
I’ve also taken a look at the England data and Covid positivity rates have been rising sharply in recent weeks in the 0-14 age groups.

Definitely one to watch in the coming weeks… Image
Read 4 tweets
Jan 30
🏴󠁧󠁢󠁥󠁮󠁧󠁿PUPIL ABSENCE - AUTUMN 2025

The DfE have now published pupil absence data for the Autumn term:

🔎 Pupil illness absence across the autumn term averaged out at 3.44% (compared to pre-pandemic average of 2.5%).

🔎 By the end of Nov, illness absence had soared to 4.7%.

🧵 Image
DfE commentary:

“The increases seen in the latter weeks of term were mainly driven by illness-related absence”

“This increase in absence is equivalent to approximately 500,000 less days in school compared to the previous autumn term.”

…e-education-statistics.service.gov.uk/find-statistic…Image
To anyone paying attention, these illness absence figures should not come as a surprise.

By early December, UKHSA was warning about how flu was spreading like wildfire through classrooms, leading to very high infection rates in school-age children (pink & green lines on chart). Image
Read 10 tweets
Jan 4
COVID & CHILD DEVELOPMENT

New US study showing impact on child brain development when their mothers are infected with COVID during pregnancy.

Results show:
🔎 Structural differences in regions of the brain
🔎Lower cognition & social-emotional scores

sciencedirect.com/science/articl… x.com/harryspoelstra…Image
And here’s another study, this time from Brazil (published Jun 2025), which also shows the impact of maternal COVID infection on child development.

At 24 months:
🔎 36% of infants exhibited cognitive delays
🔎 64% communication delays
🔎 57% motor delays

nature.com/articles/s4139…Image
And another study, just published this week (Jan 2026) in ‘Obstetrics & Gynecology’, came to similar conclusions…

“Maternal SARS-CoV-2 infection in pregnancy was associated with increased risk of adverse neurodevelopmental diagnoses by age 3 years”.

journals.lww.com/greenjournal/f… x.com/jama_current/s…Image
Read 4 tweets
Dec 17, 2025
“When it comes to flu, the focus is often on droplet transmission, but there’s also evidence of aerosol transmission. That means that ventilation & air filtration are HUGELY important.

“Are the Govt looking to improve that to help deal with all the respiratory infections?”

/1
It’s absolutely brilliant to hear Baroness Bennett raising this crucial question in the House of Lords this week.

Thank you, @natalieben 🙏🏻

You can read a transcript of the full question and response received below ⬇️



/2 hansard.parliament.uk/Lords/2025-12-…Image
Given the shocking state of ventilation in UK hospitals ⬇️…

3/
Read 4 tweets

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