UK COVID update week starting 21st May 2023

All quiet on the Weston front

I’ve not done a COVID update here for just over a month. That’s largely because there’s not a huge amount to say, really! Firstly there is less data than there used to be (the ONS survey has ended, testing and hence sequencing are at much lower levels than they were), but secondly the situation isn’t particularly exciting at the moment. ZOE is doing ZOE things lately - sometimes up a bit, sometimes down a bit, but certainly not breaking out into wild exponential growth.

Of course, this is a good thing - we are essentially fully open, close to pre-pandemic norms in terms of behaviour and daily life. But despite this, and despite having a highly transmissible virus circulating in the community, the immunity we have gained from injections and injections means that deaths and hospitalizations are a small fraction of what they would have been if we had a prevalence level of a million infections in the pre-vaccine era.

Overall I think that things that I wrote recently are holding up fine: XBB.1.16 continues to increase in market share, but my feeling remains that (as I wrote five weeks ago):

In short, I think that XBB.1.16 will cause a relatively small wave compared to last summer. It won’t be nothing, and if you are vulnerable enough to be offered a spring booster then it’s worth taking it. But it feels very much like the latest in a series of ripples, rather than a catastrophic wave like Alpha in the UK or Delta in India back in 2021.

You can see the XBB.1.16 (blue) market share increasing on this graph, but equally you can see that its growth rate is comparable to that exhibited by XBB.1.5 (red) earlier in the year. (This is based on data from this invaluable page).

XBB.1.5 did cause an increase in cases, but nothing on the scale of even last summer. That is, admissions reached about 1000 per day, in contrast to the roughly 2000 daily admissions at the height of the BA.5 wave. All this was very predictable on the basis of the growth advantage. Since XBB.1.16 exhibits a similar growth advantage to XBB.1.5 (around 7% daily), we can calibrate our expectations based on that.

Of course, the reason that this matters is in terms of the hospital pressures and deaths that previous waves of COVID has caused, and the picture there is pretty encouraging too. I described here that the numbers of beds occupied “for COVID” are as low as they’ve been for nearly two years (since before the delta surge around the time of Euro 2020).

And the trend in terms of hospital admissions remains pretty encouraging too. Albeit after a one-off change in testing procedure (which personally I don’t believe would cause sustained exponential falls), admissions continue to drop and are also at levels lower than we’ve seen for the best part of two years.

Further, the admissions ratio (rate of weekly change) remains consistently below 1, indicating that any XBB.1.16 effect on admissions hasn’t yet kicked in during the most recent data.

I think all of this goes to justify my argument (four weeks ago) that calls for increased masking were at best badly timed. In terms of the scenario I suggested there

If people wore masks for 3 weeks and then stopped, the R number would return to something close to its present level (slightly lower because we would have gained some immunity in the meantime), and things would pick up again more or less as before. A short-term return to masks in the growth phase doesn’t buy much more than a delay.

we could have already used up the public goodwill and preparedness to mask up for very little useful effect.

So overall, all seems fine. Like I say, I expect a return to modest admissions growth some time in early-to-mid June, but we will be starting from a lower base than recently, and I don’t expect it to cause huge problems.