COVID-19: April Update

Friends, I have been too busy being busy to write about the pandemic – probably a good sign.

Things are still looking good in the UK and it seems likely – but not yet certain – that the government’s gamble has paid off.

Their gamble was that a single shot of the vaccine would offer enough initial protection to prevent a surge in infections and hospitalisations and deaths as we began to re-open society.

I am not one to offer praise to the government easily, but it was very smart to increase the spacing between the two vaccine doses, even though that was not the situation tested in the field trials.

The decision to do that was a smart ‘science-based’ policy decision rather than a bureaucratic ‘cover my own back’ policy decision.

What’s happening now?

The logarithmic graph below shows positive cases, hospital admissions and deaths since the start of the pandemic.

Click for a larger version

We see that positive cases, hospital admissions and are falling roughly as fast as they did after the first wave, halving in 21 days. But deaths are falling much faster. This is probably the vaccine at work.

We’ll look at each statistic in detail later, but here I will note that – as shown by the dotted lines in the above graph – compared with 4th July 2020 when the last opening up happened:

  • Positive cases are still much higher.
  • Hospital admissions and deaths are similar.

So there is still plenty of virus ‘out there’ and still plenty of un-infected un-vaccinated people under the age of 50 who can sustain the virus in the population.

But the most vulnerable 47% of the UK population have had a single-shot of vaccine and so this is unlikely to lead to the rise in hospital admissions and deaths that we saw after the first wave.

But note that after the first wave, hospital admissions did not start to rise for a full seven weeks after cases began to to rise.

Cases

Schools have re-opened and the consequent social mixing caused the rate of decline of daily cases to slow almost to a standstill.

Click for a larger version.

Subsequently  the rate of decline has picked up again, but we must anticipate that the 12th April re-openings will result in another pause.

I will be concentrating on that pause in the next couple of weeks to see if it is indeed a pause, or – and I hate to say it – the start of a third wave.

Hospitalisations and deaths

For completeness, here are the data on hospitalisations and deaths.

Click for a larger version.

Hospitalisations (above) still seem to be falling with a halving-time of around 21 days, but deaths (below) are falling much faster.

It is hard to conceive that this result must be anything other than close to the most optimistic of projections.

Click for a larger version.

The graph above is complicated. Deaths are shown against the logarithmic left-hand axis, and vaccinations in two shades of blue are shown against the linear right-hand axis.

Supply limitations have caused the first-shot extent to slow just below 50% of the entire population as vaccines are prioritised for second shots before the 12-week delay.

Summary

Given the appalling second-wave death toll, and the generally grim start to the year, the statistics are looking better than one might have reasonably hoped for.

The next concern is the way positive cases will respond to the 12th April re-opening.

If positive cases do not rise too rapidly, then we can hope that new vaccine deliveries later in April will allow the first shot vaccine drive to reach the 75% level required for herd immunity sometime in June.

And then perhaps we could all relax for a month or two.

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