My thoughts on the govt announcement yesterday regarding a new viral strain potentially driving an increase in cases in London. The claim, at least from listening to the daily briefing seems to be based on the strain increasing in frequency more recently. 1/N

Cases have been rising exponentially in England- much of the increase being attributed to the South, although declines have slowed even in the North following easing of lockdown. Much of this is anticipated, and expected, given the behaviour of the virus. 2/N
SARS-CoV-2, like any other viruses mutates as it multiplies (albeit slower than influenza). Mutations occur randomly and most are 'neutral' - i.e. have little to no effect on transmission, ability to evade the natural or vaccine-related immune response
Having said that, few mutations have been shown to be less likely to be neutralised by plasma from patients infected by the usual (wild-type) virus. Whether this translates to a lower response to vaccines or higher risk of re-infection is unclear at the moment.
Also worth noting that just because a variant becomes more frequent in a region doesn't necessarily mean it offers a fitness advantage to the virus. Many mutations rise to different frequencies in different regions due to random processes. The frequency of strains varies globally
So the claim that the current strain is the cause for the exponential rise of cases in London isn't currently backed by strong evidence. We need to wait and see as more data emerge. It is equally possible that the rise in cases is due to easing of restrictions, given the timing.
The govt likely took action due to the exponential rises, rather than the emergence of a new strain. If the govt actually strongly believed this strain was more transmissible, they should have done much more than move London into Tier 3 (e.g.secured borders to contain spread)
Another area where the government has prematurely made claims without clear evidence at the moment. It is possible this strain is more transmissible, but the data provided briefing yesterday do not adequately back this up, in of itself. We need more evidence to make such claims.
The govt needs to be clear about the uncertainty around this, rather than making claims about cause and effect, which we cannot from the data available so far. IMO, more appropriate to link the restrictions to the predictable rise in case numbers following easing of lockdown.
Also, important to note that whether this mutated virus has important impacts on transmission or vaccine efficacy, the probability of mutation increases as we let the virus spread across the community. It's no coincidence we're seeing new viral strains.
It's a consequence of high levels of community transmission. Even if this strain turns out to be harmless, every mutational event increases the risk of a new strain emerging that may not be as harmless. If the govt wants to mitigate risk, it should aim for maximal suppression.
This is the best way to prevent emergence of new strains, and to protect our precious vaccines.
An update on this- this preprint from the @GuptaR_lab outlines what we know about the variant currently:
https://t.co/SziLXNPM8Z

More from Deepti Gurdasani

Brief thread to debunk the repeated claims we hear about transmission not happening 'within school walls', infection in school children being 'a reflection of infection from the community', and 'primary school children less likely to get infected and contribute to transmission'.

I've heard a lot of scientists claim these three - including most recently the chief advisor to the CDC, where the claim that most transmission doesn't happen within the walls of schools. There is strong evidence to rebut this claim. Let's look at


Let's look at the trends of infection in different age groups in England first- as reported by the ONS. Being a random survey of infection in the community, this doesn't suffer from the biases of symptom-based testing, particularly important in children who are often asymptomatic

A few things to note:
1. The infection rates among primary & secondary school children closely follow school openings, closures & levels of attendance. E.g. We see a dip in infections following Oct half-term, followed by a rise after school reopening.


We see steep drops in both primary & secondary school groups after end of term (18th December), but these drops plateau out in primary school children, where attendance has been >20% after re-opening in January (by contrast with 2ndary schools where this is ~5%).
We've been falsely told 'schools are safe', 'don't drive community transmission', & teachers don't have a higher risk of infection repeatedly by govt & their advisors- to justify some of the most negligent policies in history. 🧵


data shows *both* primary & secondary school teachers are at double the risk of confirmed infection relative to comparable positivity in the general population. ONS household infection data also clearly show that children are important sources of transmission.

Yet, in the parliamentary select meeting today, witnesses like Jenny Harries repeated the same claims- that have been debunked by the ONS data, and the data released by the @educationgovuk today. How many lives have been lost to these lies? How many more people have long COVID?

has repeatedly pointed out errors & gaps in the ONS reporting of evidence around risk of infection among teachers- and it's taken *months* to get clarity on this. The released data are a result of months of campaigning by her, the @NEU and others.

Rather than being transparent about the risk of transmission in school settings & mitigating this, the govt (& many of its advisors) has engaged in dismissing & denying evidence that's been clear for a while. Evidence from the govt's own surveys. And global evidence.

Why?
This is the exact problem with our government's thinking & response- despite this strategy of 'tolerating deaths' and half-way measures having spectacularly failed, it's quite amazing that our govt still hasn't learned anything, & continues to promote a policy of death. Thread


Had we adopted an elimination strategy early on, rather than one of tolerating a certain level of infection, we wouldn't be here now. The reason we're here is because the govt never committed to elimination.

We eased lockdown in May when infection levels were much higher than when other countries in Europe did this. The govt was warned about this, but did this to 'help the economy'. Not only did this lead us into the 2nd wave, the need for further lockdowns harmed the economy further

It's very clear from global evidence that we cannot 'tolerate a level of community transmission' and maintain 'R at or just below 1', which has been our governments policy for a long time. This isn't sustainable & very rapidly gets out of control, leading to exponential rises

Coupled with late action to contain these surges, not only does this lead to many more deaths, and much more morbidity with Long COVID, it also creates a fertile ground for viral mutations to accumulate with a greater risk of adaptation, which is exactly what happened in the UK

More from Government

You May Also Like

A brief analysis and comparison of the CSS for Twitter's PWA vs Twitter's legacy desktop website. The difference is dramatic and I'll touch on some reasons why.

Legacy site *downloads* ~630 KB CSS per theme and writing direction.

6,769 rules
9,252 selectors
16.7k declarations
3,370 unique declarations
44 media queries
36 unique colors
50 unique background colors
46 unique font sizes
39 unique z-indices

https://t.co/qyl4Bt1i5x


PWA *incrementally generates* ~30 KB CSS that handles all themes and writing directions.

735 rules
740 selectors
757 declarations
730 unique declarations
0 media queries
11 unique colors
32 unique background colors
15 unique font sizes
7 unique z-indices

https://t.co/w7oNG5KUkJ


The legacy site's CSS is what happens when hundreds of people directly write CSS over many years. Specificity wars, redundancy, a house of cards that can't be fixed. The result is extremely inefficient and error-prone styling that punishes users and developers.

The PWA's CSS is generated on-demand by a JS framework that manages styles and outputs "atomic CSS". The framework can enforce strict constraints and perform optimisations, which is why the CSS is so much smaller and safer. Style conflicts and unbounded CSS growth are avoided.