COVID-19: Case-Watch as at 8th October

In the face of continued rapid rises in COVID-19 cases over the past week, the number and level of localised restrictions have continued to increase across the UK. The Scottish government has also brought in temporary restrictions on hospitality across the country, with tighter restrictions for the areas seeing the highest case numbers. The data on new case numbers will be watched carefully over the next few weeks, to see if these additional restrictions help slow the spread of COVID-19. If not, tighter national restrictions may well be deemed necessary.

In this blog we look at the latest data to consider whether the existing restrictions have led to cases falling in these areas, or if community transmission remains a major concern. We also consider whether there are additional areas that might need tighter local restrictions introduced. We see how most areas are showing strong growth in case numbers. Whilst many of the “cluster” events seem to be linked to universities, the widespread growth in new cases, and the rapidity of the growth will be causing public health officials concern, especially given the limited success of existing local restrictions which have been in place for several weeks.

The overall picture on case numbers

The chart below shows the latest case numbers published by the UK government (as of the afternoon of 8th October). The bars show the daily numbers of new COVID-19 cases across the UK, with the line showing the running seven-day average, smoothing through dips in new case numbers which tend to happen, for example at weekends.

After the initial surge in March and April, daily case numbers fell over the summer months, in part as the lockdown restrictions and social distancing measures help suppress transmission rates. However, case numbers have been steadily increasing for the past few months. The concern of public health officials is that we are now seeing “exponential growth” – a rapid rate of increase akin to that seen early on in the first wave.

It is worth noting that, given limited testing capacity in March and April, it is very likely that true case numbers at that time were much higher than shown in the chart. We are now able to perform around 10-15 times more tests daily1 than at the start of the pandemic. The implementation of “Test and Trace” also means that we are testing more asymptomatic individuals now, and positive test results will now include individuals with only virus residues i.e. who have not been infectious for many days and potentially weeks. As such, the case numbers over recent months (on the right of the chart) are not directly comparable with those from earlier in the pandemic (the left of the chart).

The above chart also shows cases falling sharply in the most recent days, primarily as a result of the lag-time in obtaining testing results, as the figures are based on the specimen date. We would therefore expect the figures for the past few days to materially increase when we look at the same chart next week. For this reason the analysis below ignores the data for the most recent days, and ‘steps back’ by 5 days to what we would anticipate being more reliable case numbers. This is the largest step-back we have had to use in the time we have been producing this series of blogs, highlighting the growing pressures within the testing system as cases rise. There was also a lot of media coverage earlier in the week around the some 16,000 ‘missing’ COVID-19 cases, caused, we understand, by issues around the spreadsheet format used to aggregate results. Analysis of case numbers by reporting date reported in many media channels will show significant spikes on 3rd and 4th October as this error was corrected in the reported case numbers. However, the chart above (and analysis below) are based on specimen date, rather than date of reporting, there is much less of an impact on our analyses.  It does however serve to highlight the issues that can arise when dealing with large volumes of data.

National vs Local

The focus of attempting to control the pandemic had switched from the initial nationwide lockdown to using more localised approaches, with the intention of only putting in place restrictions in areas where, and for as long as, it is necessary. In areas like Bradford, Bolton, Calderdale and Oldham additional local restrictions have been in place for many weeks. However, over recent weeks we also have seen an escalation of the COVID alert level, and the introduction of some additional national restrictions – most notably a curfew on the hospitality industry, and a strong encouragement to return to working from home. In Northern Ireland national restrictions have largely replaced the restrictions that were in place for specific localities. Meanwhile Scotland has introduced temporary restrictions on hospitality nationwide, with even stronger restrictions across the central belt. Similar measures are also being actively considered for parts of England in the coming days.

Despite these efforts, cases have continued to rise rapidly over recent weeks. How long we can continue to use toughened localised restrictions before resorting to further broad national restrictions will depend on what happens with case numbers over the days and weeks ahead, and how these translate through into other leading indicators such as hospital admissions.  

We examine below the available data on case numbers for local areas within in each of the home nations in turn, identifying patterns over the last week and whether there are local areas where additional interventions may be required.

Our “case-watch” for England

The graphic below shows last week’s “case-watch” chart and this week’s chart side by side. We zoom in to this week’s chart later in this blog; however, the key thing for this chart is the location of the points on the chart, each of which is one of the (lower-tier) local authorities in England. Ideally the points would primarily appear in the bottom left, indicating falling case numbers and suppression of the virus. If points appear to the right of the vertical line case numbers are rising – what we don’t want to see is points primarily to the right, and especially not heading towards the top right (high case numbers and rapidly growing) as this suggests the potential need to move away from localised restrictions to nationwide restrictions in order to “put the brakes on”.

Worryingly, this week’s chart shows more points on the right side of the chart. This covers over 298 of England’s 315 (lower-tier) local authorities (an increase of 15) and around 93% of the population of England. In these authorities case numbers have risen, compared to the cases seen in the previous week.  In particular we see many of the areas where local lockdowns are in place, in some cases for a number of weeks, are still seeing high numbers of new cases. 5 local authorities also have such high growth in case numbers they have disappeared off the right hand edge of this week’s chart.

Public Health England watchlist

The points in the charts above are colour coded according to five levels of concern. Three of these relate to the weekly surveillance report published by Public Health England which explores the national and local new COVID-19 cases data for England. One of the outputs of this surveillance is a “watch-list” of local authorities1 which are causing concern, split into three categories:

  • Intervention: These authorities have specific restrictions in place which are more limiting than those in place for England generally i.e. there is some form of local restriction (“lockdown”). We mark these by the lilac dots in our chart.
  • Enhanced Support: The local authority is gaining additional support and resources from central government, including increasing mobile testing capacity (blue dots).
  • Concern: Highlighted as having high prevalence of COVID-19, the local authority is taking additional targeted actions in order to control COVID-19 case numbers. This can include additional testing in care homes and increased community engagement with high risk groups. These are marked in green on the chart.

95 local authorities appear on the latest watchlist (published 2nd October), covering 44% of the population of England. 6 of these were added over the last week (Rotherham, Barrow-in-Furness, Wakefield, Luton, Cheshire West and Chester, and Cheshire East), all but one of which were on our list of areas of concern last week, while 2 were removed (Hertsmere and Spelthorne)

Focus on this week: Which local authorities might be of emerging concern?

The “case-watch” charts above also marks several local authorities in red. These are areas not on the watchlist, but which give cause for concern either due to high case numbers, or very high (and statistically significant) growth in the new case rate. We enlarge this week’s case-watch below and highlight a number of local authorities.

Many of the areas with existing interventions have had strong growth in cases appearing to the right on the chart. For areas where lockdown is very new this may be due to the delay in restrictions taking effect. However, given some areas have had “lockdowns” for several weeks, it is concerning to see so many local authorities with interventions in place continuing to see a rise in case numbers.

The vast majority of regions are now seeing increases in case rates. It is likely that further restrictions will be required if case numbers are to come under control. Whether this can be done by tightening local restrictions, across wider areas, such as those put in place across much of the north east and north west of England, and/or whether further national restrictions will ultimately be required, remains to be seen.

Five areas in the north of England (Leeds, Liverpool, Manchester, Nottingham and Sheffield) have seen such rapid growth in new cases that they are not shown on the chart. Manchester in particular is concerning as it also has a very high case rate, whilst Nottingham also has a high case rate and so we would expect to be added to the PHE watch list this week (with Sheffield liable to move up from Enhanced Support to Intervention).

The chart also highlights how:

  • Exeter has seen a high number of new cases. Public Health officials in Devon are confident that this surge is linked to the University, with limited community transmission; as such there are no plans for imminent local lockdown. However, it seems likely that it will be added to the PHE watch list as a local authority of concern.
  • A number of places with existing interventions in place continue to have very high case rates (Knowsley, Burnley and Newcastle upon Tyne) whilst Bradford and Sefton have seen particularly strong growth in new cases.
  • A small number of areas on the PHE watchlist (Barking and Dagenham, Luton, Bolton, Birmingham and Wolverhampton) have seen falls in cases over the last week. It may be that the interventions, which in some cases have been in place for many weeks, are having the desired effect in these areas. If this continues then these areas may move off the watch list (or to a less severe rating).
  • A total of 113 local authorities (covering around 1 in 3 of the population) are areas of concern (red dots), mostly due to high growth in case numbers. If infection rates continue to grow at this pace, it is likely that they may require more direct intervention.  York and Doncaster (along with Exeter) are of particular concern as case numbers as well as growth are particularly high and would seem likely to be added to the Public Health watchlist this week.
Case numbers in Wales

Caerphilly saw the first local lockdown in Wales from the evening of the 8th September. Over the past few weeks further areas of Wales have had tighter restrictions imposed, and currently 16 of the 22 Local Authorities have restrictions in place. However, like England, there remains a combination of some tightening of national restrictions and more stringent localised restrictions / lockdowns. Details on the local restrictions in force can be found here.

We have updated our analysis of the daily case data for Wales, as published by Public Health Wales, split by the 22 Local Authorities. While there is no Welsh equivalent of the PHE watch list used in England, we nonetheless highlight in the chart below areas with local lockdowns/interventions, as well as those areas where new case numbers / growth in new cases is of concern. Note that as some areas have relatively small populations, the results can be quite volatile from week to week.

In particular, we can see that:

  • Case numbers are growing in most areas across Wales (18 of 22 areas, covering some 88% of the population). Around 80% of the Welsh population lives in areas with local lockdowns currently applied. If this continues, and with large parts of both north and south Wales now impacted, it may be that more national restrictions are considered appropriate.
  • Blaenau Gwent has seen a fall in cases over the most recent week, which will be a welcome relief. Merthyr Tydfil and Carmarthenshire have also both seen falls in case numbers (although the case rate for Merthyr Tydfil remains relatively high). It may be that local restrictions are having the desired effect.
  • Gwynedd and Ceredigion, which do not currently have local lockdowns in place, have seen an increase in case numbers, although the case rate remains below the national average. In both counties it is thought to be driven by outbreaks in student populations. Health authorities are keeping Bangor in Gwynedd on ‘active watch’ and are considering whether hyperlocal lockdowns could be necessary.
Case numbers in Scotland

Whereas England saw the first local restrictions introduced to Leicester at the end of June, the first local restrictions in Scotland were imposed in Aberdeen for a few weeks from 5th August. From the start of September local restrictions were brought in across a wide parts of the Glasgow area, increasing from 3 to 7 areas from 12th September. These restrictions were then extended to apply across all of Scotland. It is worth noting that these restrictions differ from those applying in areas of England subject to local lockdown, and that the phased easing of restrictions also mean greater national restrictions remain in place in Scotland than in England, for example on the opening of non-essential offices. (See here for more information.).

However as cases have risen dramatically, this week the Scottish Government announced a range of restrictions on the hospitality industry. Throughout the country pubs, bars, restaurants, and cafes can only operate indoors from 6AM to 6PM, for food and non alcoholic drinks only. Alcohol can only be served outdoors, until 10PM. However tighter restrictions are being brought in across the central belt, where pubs and restaurants will have to close from Friday evening until at least 25th October. Cafes can stay open but only if they don’t serve alcohol.

We have updated our analysis of the daily case data for Scotland, as published by Public Health Scotland, split by the 32 Council Areas.

We can also see that:

  • Cases are rising across most of the country, with only Dundee City seeing significant falls.
  • A number of areas across the central belt have seen rise in cases, which explains the tighter restrictions brought in this week.
  • The continued growth in new cases in City of Edinburgh will be of particular concern.
Case numbers in Northern Ireland

Localised restrictions were brought in for the first time in Northern Ireland from 10th September. Initially they were targeted at a granular level, including the Belfast area, Ballymena, and some other specific postcode areas. They were then extended to further areas such as Dundonald. Restrictions on households meeting up (including no indoor meetings) now apply across all of Northern Ireland. Last week the Northern Ireland Executive brought in further restrictions for hospitality in Derry and Strabane in the face of rising cases. Our analysis of the daily case data for Northern Ireland, as published by the Department of Health, split by the 11 Local Government Districts is shown below. 

The Derry City and Strabane area has seen rapid growth in cases over the last week, to the extent that it is not shown in the chart. It also has the highest case rate in Northern Ireland. Against this backdrop it is clear why the Northern Ireland Executive had concerns.

We can also see that every area has seen increased case numbers, with Belfast and Newry, Mourne and Down causing particular concern. 

Direction of travel

The direction of travel for new cases continues to cause concern across the UK, as the majority of areas are continue to see rising case numbers, despite the restrictions being tightened across increasing proportions of the country. It may take a number of weeks for restrictions to have the desired effect, particularly for those introduced more recently.

It is also worrying that rising case numbers seem to be starting to translate to rising hospitalisations. Whilst daily new admissions are not yet at the level seen earlier in the year, the total number of patients in hospital with COVID-19 is very close to the levels seen on 23rd March when Boris Johnson addressed the nation to put the UK into lockdown.

How long we can continue with localised rather than increasing national tightening of restrictions will depend on:

  • the effectiveness of the restrictions now in place;
  • our ability to accurately monitor local case numbers in the face of growing cases and demand for testing, particularly as we approach the winter flu season; and
  • the strain our health service starts to experience.

Against this backdrop the need for some form of “circuit breaker” to attempt to reduce more widespread community transmissions may be growing…

NOTES:

1. Pillar 1 and Pillar 2 testing – see our earlier blog which explain the Pillars.

2. For those familiar with the English local authority system these are “lower tier” local authorities – the smallest regional unit where data is readily (and publicly) available.

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