15 February 2023 Episode 317 Recent epidemiological trends in Europe

Wed, 02/15/2023 - 13:53

Episode 317: Recent epidemiological trends in Europe

Dear colleagues,

Today just an update in an illustrative way on very concurrent data from UKHSA and ECDC.



  • Two lineages are expanding: XBB.1.5 and CH.1.1, while BQ.1.1 is regressing




  • Both XBB.1.5 and CH.1.1 are more rapidly growing than BQ.1.1


  • As we know, CH.1.1 is even more immune-evasive than XBB.1.5

Ep 311-5: Panke Qu medRxiv 17 Jan 2023: Comparison of new variants XBB.1.5, CH.1.1 and CA.3.1 for neutralization sensitivity


Now, the paradox is that             “incremental” vaccine effectiveness (against hospitalization) is rather low,

while actual hospitalization numbers remain low as well!



To understand this paradox, it is important to see how this “incremental” VE is measured:

VE was estimated for those who had received a vaccine in the 12 weeks prior to testing (majority had received a bivalent booster vaccine as part of the autumn programme) as well as at least 2 previous doses. VE was estimated relative to those who were not boosted in the autumn but had at least 2 previous doses at least 6 months previously. This is referred to as the incremental vaccine effectiveness as it provides a measure of protection on top of the baseline protection from 2 or more previous doses (given at least 6 months previously), in contrast to absolute vaccine effectiveness where the comparison is to unvaccinated individuals. All vaccine manufacturers were combined in the analysis.

Since the presently circulating variants are not very sensitive to neutralizing Ab, we must admit that cellular immunity is an even more important element of “herd immunity” to keep people out of hospital. It is a reasoning “ex absurdo”, since it was not really shown.   

The figures above are all taken from UKSHA, but the situation is very similar in the ECDC report.

An interesting ECDC Table is on the vaccine uptake


Very striking is the wide range of the last column on uptake of second booster in 60+ population:

Highest (> 66 %): Denmark> Sweden = Portugal > Ireland > Belgium > Finland = Iceland

Lowest ( < 10%): Romania < Croatia < Lithuania < Bulgaria < Latvia


That’s it for now

Best wishes,