COVID-19: What next?

Friends, if you are anything like me, you are most probably sick to death of this virus. And yet it goes on.

I have been looking back at my posts over 2020 and I still feel OK about most of my comments. But as we re-open schools I thought it would be an idea to look back at where we were last September 2020 when schools re-opened.

By 26th September 2020 it was obvious that the exponential growth in prevalence which marked the start of the second wave was underway. At the time I did not imagine that twice as many people would die in that second wave as in the first. I wrote: Here we go again.

I mention this because looking up the prevalence data today (below) I notice that the viral prevalence is currently greater than it was when schools last re-opened.

Click for a larger version. This

We are probably all more versed in anti-viral protocols than we were in September 2020, but nonetheless we have to expect some increase in viral transmission and prevalence.

The difference between then and now, is that now 35% of the UK population have had a single-shot of vaccine and a substantial number of the most vulnerable are fully immunised.

We should thus expect that rising cases will not necessarily lead to the same rise in hospital admissions and deaths that we saw previously.

What’s happening now?

The ONS prevalence data (above) necessarily lags what’s happening on the ground by about two weeks.

If we look at current cases, we can see that there has been a rise in cases – or at least a slowdown in the rate of decline –  in recent days.

An unknown fraction of this rise is definitely an artefact of the large number (more than 1 million per day) of lateral flow tests being done around the return to schooling. (See the first 20 minutes of this Independent Sage Presentation for an explanation). But the exact fraction is unclear.

Click for a larger version.

So at this point it is hard to know what this rise means: whether it could just be another wiggle. Or whether it could be – and I am being serious – the start of Wave 3.

If we look at the long term graph of positive cases, we see that back in July 2020 (~Day 191) when prevalence and cases were 10 times lower, cases suddenly began to rise and kept rising.

Click for a larger version.

Hospital Admissions and Deaths did not start to rise for another 8 weeks.

Click for a larger version.

This time – the vaccine makes things different – and in 8 weeks time a full 50% of the entire population should have had at least a first shot. So we should not expect a rises in cases to lead to rises in hospital admissions and deaths.

But if the viral prevalence becomes widespread again then we risk breeding variants that can spread under the new conditions in which they find themselves.

For completeness, here are the data on hospitalisations and deaths

Click for a larger version. The pink shading shows that hospitalisations have now fallen below their trend since late January 2021.

Click for a larger version. The pink shading shows that deaths have now fallen below their trend since late January 2021. The blue line shows 1st-shot vaccinations and the light blue line shows 2nd shot vaccinations . Dotted lines show projections and trends.

2 Responses to “COVID-19: What next?”

  1. Terry Quinn Says:

    Dear Michael, In the Times today it was reported that the Irish Chief Medical Officer announced the suspension of Astrazenica vaccinations for a week “following the precautionary principle” while the apparent link to blood clots in Norway is being investigated.

    What he does not seem to have taken into account is that with about 20 people a day dying in Ireland from Covid, postponing vaccination for a week will mean that an addition 140 people will die who had they been vaccinated would not.

    Michael, am I right in this deduction? Kind regards Terry

    Sent from my iPad Terry Quinn CBE FRS

    >

    • protonsforbreakfast Says:

      Terry, how lovely to hear from you. I trust you and yours are well.

      I don’t think the likely “extra death” entailed is quite as bad as 140 deaths. In Ireland (as in the UK) the bulk of the work in reducing the epidemic prevalence is being achieved by the lockdowns of various degrees. Vaccinating people reduces R and the prevalence falls faster. The relative effects of the two depend on many factors

      So one needs to compare prevalence falling at rate R#1 without the AZ vaccine and prevalence falling at rate R#2 with the vaccine. In the UK I have looked hard to see the effect of the vaccine and even with out high vaccinated fraction, it has only just appeared – to my eyes – since the last week of February.

      But the wider question is the balance of risks from the point of view of the Chief MO. And I think some cognitive biases are at play here. Active actions such as vaccinating appear to be different from passive inaction. Harms resulting from the vaccination are the CMO’s ‘fault’. Harms resulting from not vaccinating are the virus’s ‘fault’. I consider this distinction illusory but the use of the phrase ‘precautionary principle’ implies to me that that is how it is being seen. I think also that there is an unspoken anti-UK bias in the questioning of the effectiveness of the AZ vaccine in many EU countries that makes decisions to suspend it politically easy.

      Anyway – stay safe.

      Michael

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: