COVID, flu, RSV – week 45 update

My recent The Conversation article on COVID, flu, RSV – how this triple threat of respiratory viruses could collide this winter was based on the UKHSA data from week 44 (covering weeks 1-43 of the year 2022).

The data were updated yesterday, so I can look at how the picture has changed since last week.

TL&DR: COVID-19 cases are down, flu is up, RSV cases are up, and common colds follow the same pattern as in pre-pandemic times.

COVID-19

Covid cases continued to drop, as does positivity. The positivity reading from last week was corrected upwards (from ~9% to ~11%), so I expect the most recent reading of ~7% to go up as well. However, the trend down is very clear.

However, COVID pandemic is not yet over and there is still a large uncertainty over where we are going next. The following figure did not make to The Conversation, but it compares the IHME predictions and actual death data for England. Note massive confidence intervals!

Seasonal influenza

This winter’s outbreak is early and large. Difficult to predict, as there is quite lot of variability across years. Note that last week’s reading was updated from ~250 to over 300 positive samples, so I expect this week’s reading of ~170 to be corrected upwards.

RSV

Not a lot of change since last week. A little dip in numbers in weeks 42-44 is related to the school break in many areas of England – can be seen in 2018 and 2019 records as well. Expect numbers to continue going up; it is hospitalisation that we need to watch.

Coronaviruses

I could not find UKHSA published numbers for non-COVID coronaviruses. Canada publishes similar data, so here is a graph a couple of weeks back:

I expect “business back to normal” on this after a very low 2020-21 and high (and unusual) 2021-22 seasons, peaking in February-March.

Rhinoviruses

UKHSA does not publish data for Rhinoviruses (or at least I could not find them) so this graph is a digitised version of one from their report. Not a huge change since last time and as with RSV and Coronaviruses, we seem to be back to “normal” – which does not mean it is good!

Comments on “triple threat” article

I have been asked a question related to the COVID-19 data I included in my The Conversation article on COVID, flu and RSV:

It is related to the first figure in my article:

AK/UKHSA

In this graph, the cases (“Pillar 1 episodes”) go down while the positivity (the proportion of tests which are positive) goes up. These two data seem to contradict each other.

So, are the COVID numbers going up or down?

The answer might be more complicated, but I suspect the main reason is the testing intensity. If the “true” number of cases is roughly the same, but the number of tests goes down, the “reported” number of cases will also go down.

If we tested completely randomly (or is compulsory), this should not matter to the proportion of positive tests.

Of course, the more we test, the more accurate the predictions are and the smaller the variability, but the results will be consistent:

But, in reality, testing is not random. People will only be subject to testing if they have symptoms or are more at risk. As a result, the fewer the tests, the more likely it is they catch positive results:

Here, we focused on the “cluster” of cases in the middle. So, what can we say about the “true” number of cases of COVID-19 in England in 2021 and 2022?

There are other sources of data, for example the Zoe app, catching those with symptomatic COVID. The graph below only captures the last three waves, March-June 2021, June-September 2022, and September-November 2022. The first two are about the same, whereas the most recent one is smaller.

The number of deaths is another indicator, with the advantage of not being dependent on testing.

If you line up all waves since the summer of 2021, the number of deaths looks very similar, except for the two large omicron waves:

The most recent wave (September-November 2022) is similar to the June-September 2022 one but appears to have peaked earlier and at a lower value. In contrast, the March-June 2022 wave was much higher, almost as high as the omicron peak in October-December 2021.


There was a question about Australia’s influenza data. In my article, I used internet sources to state that in 2022 Australia experienced the worst flu season in 5 years.

I did not do a detailed analysis of hospitalisation and other data; apparently they show that the season was not as bad. But, I did use WHO FluNet notifications:

On COVID, seasonal influenza, RSV and other viruses

COVID, flu, RSV – this triple threat of respiratory viruses could collide this winter. But how can we realistically expect the winter to play out?

In this new piece for The Conversation, I look at COVID19, seasonal Influenza, RSV, other coronaviruses and rhinoviruses. I compare how their cases looked before and during the pandemic, and what the outlook is for this winter.

TR&LD: Flu and RSV cases are up, but the real clincher is how big the next COVID wave will be, as Covid Isn’t Over!

Finishing this piece was a bit of a struggle, as I have been down with #COVID myself (reinfection) following two months of chronic laryngitis.