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New Year’s update on selected infectious diseases in England

Happy New Year to all my readers and followers! TL&DR: The apparent collapse of the NHS is not due to the unprecedented numbers of cases.

Covid wave has slowed down although it is expected that it will pick up later this winter. RSV has definitely peaked, with flu cases possibly unreported creating some uncertainty about the peak. Scarlet fever cases are very high.

The data for major diseases in England have just been released, so here is a quick update on where we are with the major diseases. Bearing in mind that this is a festive period so the numbers are usually lower due to reporting, and also likely to change in the next week’s update.

Covid

The wave is definitely in. I am pretty sure the last point (week 52) will be revised upwards next week.

I still think that barring a new variant, this wave will be similar to the earlier ones this year – optimistically, the Autumn wave, but perhaps more realistically the two Spring ones.

The current trajectory lines up quite well with the death records over all the previous waves, except the two early omicron ones (December-March and March-June).

RSV

RSV is clearly past the peak. Moreover, as the graph above shows, the actual number of hospital admissions was lower than in the pre-pandemic years. So, it looked bad, but turned out to be better than expected.

Influenza

Influenza epidemic is where the main actions seems to be at the moment. The last two data points suggest we are riding the wave’s crest and following the 2019-20 pattern. If that holds over the next couple of weeks, we can expect a quiet spring.

But, as in the previous weeks, I expect the last two readings to be revised upwards and then we could enter a big flu year territory.

Scarlet Fever

This is not routinely reported by UKHSA and needs some digging in, but given interest in this disease, I decided to add it to the overview. I will be studying this very interesting graph in more details in future posts, but a couple of observations about the current year.

Firstly, notice the logarithmic scale. As a result, the 2022-23 outbreak is clearly unprecedented.

I do not know what to make of the week 50-52 readings with a jump of 20,000 cases in one week; I suspect part of it is due to reporting – cases from the previous weeks accumulating in the subsequent times.

Another hypothesis of a superspreader event (or events) is contradicted by wide geographical spread of cases. So, if genuine, this looks like a big and unusual outbreak, but the one that has been growing over the last season (notice the yellow line of 2021-22 data).

Moreover, comparison with other years suggests that we are not finished yet and I expect more cases – perhaps not as many as 20,000 per week, but certainly in the 4-digits range.

Week 52 – quick update

It is a festive season, and UKHSA is not providing updates on Covid numbers in England. Scotland is still publishing daily updates, so a quick look at where we are with Covid. The new wave is already in England and Scotland data, particularly in the older age groups.


This is the last post this year, so please accept my best wishes for the new 2023 year.

Week 50 updates – what is in store for the “third Covid Christmas”

It has been another week, and new UK data are out. This is an update on where we are with the main viral infections.

TL&DR: Good news: RSV wave turned out to be smaller than anticipated and hopefully is on the decline. Bad news: Flu is on the rise. Covid cases continue to go up in the “winter” wave. The attention is shifting to Strep-A and Scarlet fever (about which a separate blog post after Christmas).

The outlook published in my The Conversation article seems to still hold, although I probably underestimated the speed at which the outbreak in China is progressing. Thank you again @Phoebe_Roth for your support.

RSV

A few weeks ago, there was a lot of concern about the RSV outbreak. The overall numbers appeared high, but it was hospitalisation that drew a lot of attention.

The actual hospital admission rate turned out to be lower than in the pre-pandemic years, and it now seems to decline. The positivity – the indication of how many infections there are in the population – is declining in the two mostly-affected classes, 0-4 yo and 5-14 yo. We are not out of the woods yet, but unlike in 2021, the outbreak seems to be back to “normal”.

Influenza

I was looking at data last week (see below, left figure) and considering how closely the positivity in 2022 matched the 2019-20 season. I did not provide an update last week but I thought that the next week would be critical in establishing how bad the season was going to be.

The week 49 positivity has been revised upwards, and week 50 brought even higher numbers. The number of positive samples has also been revised upwards, and it does look like we are for a record-breaking flu season this year.

Covid

Covid case numbers and hospitalisation rates are both increasing, as expected.

I still think the wave will not be a big one, although in terms of deaths, it could be as bad as the one in late Spring and early Summer of 2022. The IHME predictions seem to agree with this scenario, although they do not have a stellar record of predicting England’s data.

Shaded area corresponds to 95% confidence interval. IHME predictions are scaled and moved in time to match the UKHSA data.

I have so far been over-pessimistic in my Covid predictions and indeed thought the Autumn/Winter wave would be larger. But I am now cautiously optimistic; I think there is enough immunity (infection- and vaccination-driven) in the population to keep the Covid infections ticking but not erupting.

The last few points in the current outbreak are low due to reporting delays. They are usually revised upwards in the next few weeks.

Essentially, omicron is now “mopping up” those who have lost immunity, and the cycles are triggered by increases in contacts – schools and holidays. Unless we get another particularly nasty variant – and it does not seem so at the moment – we will continue with this pattern for months if not years.

English data are now published weekly so the graphs above are for up to week 50. Scotland still publishes daily data; the current wave seemed to be slow in starting north of the border, but it is clear now, particularly in 65 year olds and older. These are cases and so difficult to interpret.

Strep-A and Scarlet fever

The public attention is now shifting to a Strep-A and Scarlet Fever outbreak which is particularly bad this year. This will be the topic of my next post, but it will now need to wait until after Christmas.


This is my last post before a break for the holidays. I want to wish you, my esteemed readers, a Merry Christmas and a Happy New Year! May this festive period bring you peace, joy and rest.