Freedom Day

Paddy Alton
3 min readJul 19, 2021

So, it’s ‘freedom day’, and rather inauspiciously the Health Secretary has (mild) COVID and both the Prime Minister and Chancellor of the Exchequer are self-isolating.

So what’s going on? Unfortunately, the emergence of the Delta variant of COVID has changed the landscape in several important ways. Crucially, it is much more transmissible — and while vaccines remain highly effective against it, they are less successful at preventing transmission.

In March last year (see here) I talked about vaccines being the main exit strategy from the pandemic. That remains true. They are not magic, but — just as since the early 2000s the UK has systematically used them to mitigate the annual flu season — they greatly reduce the human toll the disease takes.

I previously had cause to hope that vaccines could also be used to reach the herd immunity threshold — the critical point where so many are protected that the virus usually can’t find another viable host during the infectious period and therefore dies out. Unfortunately, Delta has made that very challenging due to its higher infectiousness. The only way to do it now would be to vaccinate teens and children, something we should be extremely reluctant to do given the relative risk younger people face from COVID vs the unknown risks of a vaccine that was extensively tested in adults.

Given that our existing public health measures (a hodge-podge of things we threw at the virus, mostly well-motivated but done on the balance of evidence rather than because all of them are well-understood) are not sufficient to stop the current growth in cases, this means we aren’t truly out of the woods yet. While hospital admissions are currently low, they are growing exponentially (doubling every 2–3 weeks) so the opening up must be carefully monitored to avoid the kinds of pressures on the health service we saw at the start of the year.

Nevertheless, the vaccines are having a powerful effect, better hospital treatments for COVID are now available, and we finally have a functional test-and-trace infrastructure … although we should be careful that alerts from the app really reflect the risk of transmission from a close contact in the context of a highly vaccinated population (and either way I think there’s a real case for using testing to let people — especially key workers — leave isolation earlier).

In the chart below (from the FT) we can see the vaccine effect:

We can also see that in other parts of the world the story is very different. Public health measures that previously controlled COVID are insufficient to stop Delta, and countries unable to afford an effective vaccination programme are paying the price. I think the moral case for the UK becoming a vaccine exporter is now unanswerable in the face of this humanitarian crisis — if nothing else, the danger of yet more variant strains arising is a real one.

Meanwhile, for us the road ahead may be more difficult than hoped. Given that existing measures are not able to restrain Delta, a large number of cases are coming — almost regardless of the opening up (short of another lockdown, which of course is a far-from-costless solution that I think we have to avoid if at all possible).

For me, the shift from legal responsibilities to personal/organisational responsibilities is a side-show: in practice, people already take their cues about social distancing/ventilation/mask-wearing/hand-washing from supermarkets, train operators, their workplace, and people around them … regardless of which of these (realistically unenforceable) measures happened to be codified in law (NB this is quite different to imposing legal obligations around lockdown previously and test-and-trace, which continues). What’s important is that we have a strong message now on the need to continue to support the vulnerable at home (e.g. immunocompromised people) and abroad.



Paddy Alton

Expect articles on data science, engineering, and analysis.