Another look at the COVID data – and a hypothesis

I’ve been having another look over the hospitalisation and deaths data following this tweet from Oliver Johnson.

Oliver is not an epidemiologist, so in that respect he is a layman like me. However as a maths and stats professor, his observations of the data throughout COVID have been helpful throughout the pandemic, so worth paying attention to here.

Here’s what has been happening with the data on hospital admissions

And here’s the death’s.

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What we can see here is that in both cases, the numbers have been substantially lower that at times when case rates were comparably high prior to the vaccines (e.g. October last year), the result is that in the big scheme of things the picture is fairly flat. If we zoom in a bit closer on the data for deaths we get this picture. Deaths increases in line with the rising case numbers a month in advance until the end of August when there was a small drop followed by an increase and it appears that things have levelled off again afterwards.

We know that the vaccines are highly effective at reducing transmission of the virus and preventing serious disease and death. However, they are not 100% effective.  A percentage of people will still get the illness and a smaller percentage still will end up in hospital.  There will then be a proportion of them who experience severe illness.

So, here’s my hypothesis. Remember that it comes from a layman, so add in a tablespoon’s worth of salt for good measure.  The number of people who are susceptible to severe disease and death is likely to be a fixed number. I suspect that whilst there is a level of disease prevalent in society that is significantly higher than the proportion of the population who remain vulnerable to severe disease then we are unlikely to see those numbers changing much. They won’t go up very high when cases rise and nor will they decrease greatly as cases fall, until you hit a lower threshold where case prevalence is so low that they are significantly less likely to come into contact with people who have COVID.  I don’t know what that number is but suspect it is much lower than the 35k daily average in new cases we are seeing at the moment.

If I’m right then I suspect we are getting a feel for what it looks like to live with a disease that is becoming endemic, at least over the short term. As we become more exposed and used to COVID-19 then that may lead to a further reduction in hospitalisations and deaths but it will take time.