COVID-19: Case-Watch as at 1st October

Increasing numbers of local authorities across the UK have localised additional restrictions in place. In recent days we’ve seen further areas put such restrictions in place and existing restrictions being tightened further, both for specific regions as well as broader areas such as much of the north of England. 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 be deemed necessary, for example a short “circuit break” of much stronger restrictions over a short period.

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.


The overall picture on case numbers

The chart below shows the latest case numbers published by the UK government (as of the morning of 1st 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.

The number of cases across the UK rose rapidly over March, as COVID-19 began to spread though the population. After this initial surge subsided, 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.

Care is needed though when looking at this chart. It is tempting to compare the second half of the chart (July onwards) with the early part. This can lead to the false impression that new cases now are running similar to that seen in March and April. Testing capacity was very limited initially and only available to those in a clinical setting. It is very likely that community infection numbers at that time were much higher than shown in the chart. In contrast to March/April, testing capacity has significantly expanded. We are now able to perform around 10-15 times more tests daily1. Owing to “Test and Trace” we are also testing more asymptomatic individuals now, and the test results will include individuals with virus residues i.e. who have not been infectious for many days and potentially weeks.

The above chart also shows cases falling sharply in the most recent days. We caution against viewing this as new cases “stalling”. It is primarily as a result of the lag-time in obtaining testing results, as the figures are based on the specimen date. We would therefore anticipate that the figures for the past few days will 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 4 days to what we would anticipate being more reliable case numbers.

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 Scotland and Northern Ireland national restrictions have largely replaced the restrictions that were in place for specific localities. Meanwhile further restrictions are being brought in across large parts of northern England, in addition to those already in place.

Despite these efforts, cases have continued to rise rapidly over recent weeks. Whether (and for how long) we continue along a route of localised restrictions, potentially with increased restrictions, or instead use more sweeping national restrictions, depends on whether we see case numbers fall in the weeks ahead.  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 many more points on the right side of the chart. This covers over 283 of England’s 315 (lower-tier) local authorities and around 92% of the population of England. In these authorities’ cases 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.

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.

91 local authorities appear on the latest watchlist (published 18th September), covering 40% of the population of England. This included all the London boroughs (and the City of London).

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.

The chart also highlights how:

  • Liverpool, Newcastle upon Tyne and Birmingham have seen particularly strong growth in new cases
  • Knowsley and Burnley have seen very high case rates – both are in the top 3 of case rates in the UK (with Liverpool and Newcastle upon Tyne in the top 5).
  • Birmingham continues to see large numbers of new cases, and a material growth in new cases, despite restrictions being in place for several weeks. Similarly, Bolton, Bradford and Oldham where restrictions have been in place for 8 weeks, continue to see very high new case numbers.
  • A total of 52 LTLAs (some 18% 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 in the near future.  Of particular concern are Craven, Rotherham and Walsall where case numbers are also particularly high and would seem likely to be added to the Public Health watchlist this week..
  • All the London boroughs (and City of London) were added to the latest PHE watchlist at the ‘Concern’ level. These areas are most of the green dots clustered around (and behind) the concentration of red dots.  The growth in new cases across the capital seems to have driven this decision, potentially fuelled by concerns with how cases have rapidly increased, and then stayed high, in other major metropolitan areas. It is likely that local health officials will be monitoring things carefully.
  • A small number of areas on the PHE watchlist (Rossendale, Blaby and Hertsmere) have seen falls in cases over the last week. It may be that the interventions 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).

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, all in the south. Most recently four councils in north Wales (Conwy, Denbighshire, Flintshire, and Wrexham) have announced local lockdowns from 1st October, bringing the number of areas with restrictions to 16. 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.

In particular, we can see that:

  • Case numbers are growing in most areas across Wales. Around 80% of the Welsh population lives in areas with local lockdowns 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 the highest case rate in Wales, and amongst the highest in the UK. Merthyr Tydfil is also seeing high growth in cases.
  • The four areas highlighted last week as giving cause for concern due to high growth in cases (Cardiff, Carmarthenshire, Swansea and Vale of Glamorgan) all have high growth in new cases have all seen local lockdown introduced over the past week (although only for the town of Llanelli in Carmarthenshire rather than the whole area). Cardiff and Swansea in particular have seen high growth in case numbers over the week.
  • Case numbers are continuing to fall in Caerphilly, where the local lockdown has been in place for three weeks, and Newport.

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 last week. 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.). In addition, concerns around outbreaks in university accommodation resulted in students across Scotland being asked not to visit pubs or restaurants over the weekend.

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

The area of biggest concern is Glasgow City, where the weekly rise in case numbers has been such the it does not appear on the chart above (as it is beyond the limit of the x-axis). This is, in part, due to local spikes, including amongst returning university students.

We can also see that:

  • Cases are rising across most of the country, with only the Scottish Borders seeing significant falls.
  • The continued growth in new cases in City of Edinburgh will be of particular concern.
  • North Lanarkshire and South Lanarkshire, in the Greater Glasgow areas, are both seeing high case numbers, along with Dundee City (which has also seen an outbreak in university accommodation).
  • In better news, West Dunbartonshire, which was causing concern last week, has seen a small fall in cases.

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, bringing the total number of impacted postcodes to over  10,000 postcodes. Restrictions on households meeting up (including no indoor meetings) now apply across all of Northern Ireland, and the Northern Ireland Executive is said to be considering further restrictions as cases rise.

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. 

We can see that:

  • The continued rapid growth in new cases in Derry City and Strabane will be of particular concern. Given that COVID-19 rates are amongst the highest in the UK, it appears likely that further restrictions will be required to attempt to bring cases under control (and as we were going to press we learned of the toughest local restrictions in the UK being introduced).
  • Large increases in cases have been seen in a number of areas, including Belfast and Mid Ulster.
  • More encouragingly, a number of areas, including Ards and North Down and Mid and East Antrim, have seen cases fall over the past week.

Direction of travel

The direction of travel for new cases continues to cause concern across the UK, as the majority of areas are seeing rising case numbers, despite the restrictions in place across broad swathes of the country.  Whether, we can continue down a path of localised rather than national tightening of restrictions will depend on the effectiveness of existing restrictions and the confidence in our ability to continue to accurately monitor local case numbers in the face of growing cases and demand for testing.


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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