#BA.3.2
So it seems really true that BA.3.2 preferentially infects small children or is particularly severe in small children:
Compare the early German BA.3.2 fraction size peak in mid December (figure @rv-enigma.bsky.social) to case number based incidence in the age groups.
7d incidence in the 0-4 age group almost reached the level seen in the much larger 2023-2024 wave.
Since the abandonment of testing in spring 2023, case numbers are mainly hospital-derived. Therefore, virulence and infection numbers cannot be discriminated with this measure.
Scotland saw a similar pattern with remarkably high hospital admissions in the age group 1-4 end of February (HT
@catlove40476297.bsky.social
). This seems to correlate with BA.3.2 fractions reaching high levels.
Variant figure: https://x.com/gwladwr/status/2032059098578006423?s=20
Hospital data:
https://scotland.shinyapps.io/phs-respiratory-covid-19/
In Swiss case numbers, 0-4 show higher incidences than 65+, lately. This was never seen since BA.1.
Not sure this fits to local BA.3.2 fraction sizes. It well might.
Case numbers will be mostly from severe/hospital. They are currently lowest ever since the advent of Omicron.
Addendum:
The stacked area graphs are a bad way of representing age group specific incidences, as those cannot be added.
Incidence is specific to each age group; each age group has a different size.
For example, the 0-4 age group (5% of the population) has ca. 2/3 the size of the 80+.
I chose it on the fly, yesterday night, to be able to gauge the trajectories over time and compare between individual age groups.
Here a non-stacked figure (left), and a look at ratios between 0-4 and 80+ as well as 5-14 and 80+ (right).
The suspected BA.3.2 signal is also in the 5-14.
I have no explanation for the high 0-4 / 80+ ratio in the low absolute incidence period preceding the wave. Differential testing intensity?
Dominik Steiger
DrYak