Just because cases and deaths are low now doesn’t mean we won’t be in another crisis leading into a lockdown in a few months time. This is preventable, but only if we act early.

First published in June 2021.

Media focus on 21 June is a distraction. Of course, further opening on 21 June should not happen, but this focus suggests things will be OK if just this is postponed. They won’t.

The big question isn’t about what happens then. It is about how we deal with the crisis now.

So, why do I say this is a crisis? Here is why: we are seeing rises in cases, hospitalisations, and deaths, even though numbers of deaths are still low.

But the rate of rise is important: a 27% increase in cases in one week in the UK and a 23% increase in hospitalisations.

Covid Dashboard. | UK Gov

This masks a heterogeneous picture, with very rapid rises in some parts of England where the Delta variant (B16172) is dominant – where rapid exponential rises are being observed.

Does that mean this is localised? No.

Sequencing data from the Wellcome Sanger Institute on 22 May (excludes travellers) shows this is widespread in the community, being dominant in many areas. This explains why surges are being seen in many parts. Maps for the 8 May and 15 May are also shown for comparison.

But how can we be in a crisis when cases are low?

Yes, cases are low, but exponential spread is unforgiving once R rises above 1 – and it is above 1 now. The number of cases is at a similar level to where it was in mid-September and cases almost tripled in four weeks.

Covid Dashboard. | UK Gov

And this variant is more transmissible than earlier variants. Public Health England (PHE) data shows ~67% increase in infection in contacts of the Delta variant infected cases, compared to those with the Alpha variant (secondary attack rates 13.5% vs 8.1%).


And we know this variant has been doubling week on week amidst restrictions – including prior the 17 May – which indicates an R of ~1.6 for the variant even prior to the 17 May. At this point in time the variant was growing twice as fast as the Alpha variant B117.

This provides an idea of the fitness of this variant over and above the fitness of B117, which was already 60% more transmissible than previous variants. It also is an indicator level of restrictions that might be need to contain spread.

Although the variant is rapidly gaining ground, it hasn’t fully replace B117 yet. While this is good, it also means we aren’t seeing the full impact of the variant yet – as the variant replaces B117, we will see R increase further, in line with this.

This means that the rate of exponential growth is likely to change over time. Of course, there will be other factors that impact this. Half term may mitigate this to an extent, given much of spread is happening in schools, but growth will likely continue.

We are just beginning to feel the impact of the 17 May opening, prior to which variant cases were already growing with an R of 1.6. This was before mask recommendations were removed from schools and before indoor mixing and gatherings were allowed.

SAGE modelling of a variant that is more transmissible shows that high transmissibility alone with continuing vaccination would likely lead to a wave of hospitalisations exceeding January 2021 and that is just with Step 3. Moving forward with Step 4 makes this worse.

Road Map Scenarios and Sensitivity: Steps 3 and 4.

Adding a degree of escape from vaccines (e.g. reduction in effectiveness against preventing infections, even a high level of protection against severe disease is preserved) makes this wave even larger. It is clear that we are seeing significant escape with vaccines currently.

If the effectiveness against symptomatic disease is reduced (more so for the first dose than for two doses), it is very likely that effectiveness against infection and transmission is also reduced, even if protection against severe disease were preserved. All of this is very concerning.

The point I am trying to make is that it is clear that even if we move forward as we are, and don’t open up further on 21 June, we are still likely to face a wave exceeding the one of January 2021 – so, postponing 21 June isn’t sufficient.

And it distracts from the urgent need to act now.

Just because cases and deaths are low now doesn’t mean we won’t be in another crisis leading into a lockdown in a few months time.

If we have learned anything from previous waves it should be that we need early aggressive action. Waiting leads to more deaths, more Long-COVID, more opportunity for virus adaptation, longer restrictions, and prolonged lockdowns, with all its impacts on the economy and the society. We need to pre-empt this.

Vaccines, while helping reduce the impact of the next wave, won’t ensure that this won’t overwhelm the NHS – just 38% of our population is fully vaccinated, the rest being either unprotected, or incompletely protected. High levels of infection can still result in many deaths.

Worryingly, we are already seeing adaptation of the Delta variant (India 2, B16172) in different settings, e.g. Vietnam recently reported a surge in cases possibly linked to B16172 associated with some mutations from B117. We are seeing evolution now, even within the UK, where sub-lineages of B16172 with mutations like from the Beta variant (e.g. K417N) have been identified.

These numbers are small, but highlight the huge potential for adaptation of the virus, if we let this happen.

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So what can we do now?

  1. We urgently need transparency from the government. We can’t tackle what we can’t see. All data points to rises in infection in school-age children – but the government seems to have suppressed data on variant outbreaks in schools;
  2. We need mitigations in schools now. This means masks, ventilation, smaller bubbles, class sizes, and social distancing. There have been many outbreaks in schools that have led to school closures. We need to protect children, families and ensure schools remain open safely.
  3. We need comprehensive border policy with managed quarantine not red lists. The Delta variant B16172 was in the UK in late February, even before it was identified as a concerning variant in India (24 March) and well before it was put onto the red list (23 April).
  4. We need a complete reform of our test, trace, isolate and support systemwhich failed us again during spread of the new variant across England. A lack of support for isolation also really impacts the impact of all forms of testing including surge testing.

These are measures that need to be put in place now irrespective of what happens on 21 June. It is important that the media don’t lose focus of what is happening now. We can’t afford to push the NHS any further, given the number of people waiting for routine care. Not to mention the hundreds of thousands who could end up with Long-COVID, and thousands more deaths. And the impact of delayed action, which could result in another lockdown, with all its negative consequences on the society and the economy.

All this is preventable, but only if we act early.

This virus isn’t going to stop adapting unless we do something to prevent this. It is vital that we keep cases down as we roll out vaccines, to protect our vaccines. Every new variant is a huge risk to the global pandemic response and to our vaccines

Going Further:

Dr Deepti Gurdasani, Senior Lecturer in Epidemiology, Statistical Genetics, Machine Learning, Queen Mary University of London.


[This piece was first published as a Twitter thread and turned into the above article on 1 June 2021 with the purpose of reaching a larger audience. It has been minorly edited and corrected, and published with the author’s consent. | The author of the tweets writes in a personal capacity.]

(Cover: Flickr/Tim Dennell. - Sheffield. | 15 June 2020. / Licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.)

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