Here in Wales we now appear to be dealing with not one but two different threads to our pandemic. If you look at todays stats the divide in the country is very clear. In the South including Carmarthenshire and Ystradgynlais MSOA the picture is one of rapidly increasing case loads
most with case rates over 500/100k and testing returning positivity rates of 25% +-2%. In the rest of Powys, Pembs, Ceredigion and the Northern Counties rates are significantly lower peaking at 310 in Wrexham and positivity is 8% +-5%.
Contrast this with the week after the end of lockdown and and you see a stark change. At that point Blaenau Gwent was highest at 350/100k and positivity ranged from 3 to 20%.
In the intervening weeks case rates have broadly doubled in the Northern area and positivity shaded up by about 5% in the south are 3 to 4 times greater and positivity has risen by 7-10%. Even where caseloads were broadly the same Wrexham 152 and Torfaen 176 there has been massive divergence 319 vs 672 today.
The first question is why? Everyone is under the same restrictions so unless you believe (I don't) that South Wales is full of hedonistic lawbreakers you can rule out behavioural differences. Likewise rurality can be ruled out as Monmouthshire and Carmarthenshire are in line with the rest of the southern area all be it at the bottom of the local stats. So if you remove human behaviour you are left with the virus itself.
PHW have already confirmed that the strain first identified in Kent in late September also showed up in samples from S Wales in November. We know from English data that infection rates in Kent were increasing from the 2nd week of lockdown onwards and since measures were eased there has been a steady spread out first into Essex and East London and in the past week across Surrey and East Sussex with a further cluster in the Portsmouth area.
So now we have a new (Kent) and old (Spanish) strain in S Wales but only the old in the North. However in Wales the Kent strain was in an area without major restrictions in place so as it expanded under lockdown in England it exploded in the more relaxed Welsh context.
Meanwhile in N Wales the old strain was still largely contained with R clearly just above 1 but not by much.
So what can be inferred
1 We now have two strains present in Wales
2 The natural state of R seems to be higher in the strain circulating in S Wales
3 The changes to hospitality seem to be working in the North but have no impact on the Southern strain.
Now we come to the key bit. Hospital admissions peaked in the middle of lockdown and fell back until 2 weeks after then end and have steadily risen ever since. If we accept they are a lagging indicator of about 14 days they currently represent infections that were occurring at a time when infections were across S Wales running at about half what they are now. This means there is a significant spike locked in already that will feed though between Christmas and the New Year. Worse the rate of doubling in S Wales seems to be about 13 days (and possibly slowing slightly) this means by the time we reach implementation of Level 4 measures we are likely to be seeing infection rates of more than 1 in a 100 across the entire region in the first week of the new year.
For me the situation is quite clear never mind Christmas S Wales should be entering Level 4 NOW.
Notes This draws on information which is freely available in the public domain from PHW. As such it's an analysis of patterns in data linked to published information it is not an academic study and has a number of gaps mainly because there is nothing published. As such it is based on a number of easily tested assumptions
1 The Kent strain is the driver of infection in S Wales (FM stated it was in Wales in Nov but not its extent since)
2 That strain is still contained within that area (see above)
3 It is more infectious that the previous strains and hence has a higher natural R number (lockdown measures in England were insufficient to stop infection rates increasing in Kent suggesting the reduction from the actions failed to bring R below 1 unlike in the rest of the country and hospitality changes in Wales have not seen a levelling off and fall in infections in Wales)
Comments