West Sussex COVID-19 data summary

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West Sussex COVID-19 data summary

West Sussex County Council Public Health Department monitors COVID-19 related information on a daily basis, and a summary pack is published as a powerpoint slide deck which can be found on the top right of this webpage. Links are provided to public data sources available.

A mobile friendly, quick glance, version of this site is also available (https://wsx-c19-mobile.netlify.app/).

Although this webpage has been made by a member of staff in the Public Health and Social Research Unit to support their work, it is not a West Sussex County Council website.

For more information please contact publichealth@westsussex.gov.uk

This page works best in certain browsers such as Chrome, Firefox, and Safari, and does not currently work well in Internet Explorer. If you have difficulty viewing the charts on this page please consider using a different web browser.

This analysis has been created by Dr Rich Tyler at the West Sussex Public Health and Social Research Unit.

A powerpoint slide deck is available to download here

Data source: https://coronavirus-staging.data.gov.uk

The heatmap visualisation shows a quick overview of confirmed cases over time and across areas with each tile representing a day colour coded by the number of new cases (the darker red tiles denoting more cases). You can toggle between viewing the coloured tiles as actual confirmed cases or as confirmed cases per 100,000 population.

The cumulative cases are taken from the most recently available date, although number of confirmed cases in a single day (a proxy for new cases) is taken from six days prior (latest complete date).

The colour key for the tiles has been chosen to capture the breadth of new cases across the region, whilst being sensitive to small numbers as well as periods of no reported cases.

Daily case changes

The figure below shows the daily confirmed cases of Covid-19 over time by area (showing West Sussex by default), but you can change this to any lower tier area within the county as well as the South East region and England for comparison. The black line represents the rolling average number of new cases confirmed in the previous seven days.

Case results are generally published in the afternoon and represent cases reported up to 9am of the reporting day. However, cases are assigned to the date on which the specimen was taken rather than when it was reported. It would be very unlikely that a specimen would be taken on the day of reporting with results returned by 9am. It can take as many as four days for results to be reported (e.g. specimens taken on 1st August may not be reported until the 5th). As such, we consider the last four days as incomplete as more cases may be added to the totals for these days.

The figure includes key dates when changes to testing capacity and eligibility were announced. These are adapted from The Health Foundation Covid-19 Policy Tracker.

Area:

Data source: https://coronavirus-staging.data.gov.uk

The grey lines with circles at the top show dates on which the Covid-19 testing eligibility criteria was amended to include a wider population. Hover over each point to see which population groups were added to the test eligibility criteria.

The red lines with circles at the top show dates on which restrictions were added and eased, starting with the national lockdown on 23rd March 2020. Hover over each point to see key changes.

Note that the scale may change as a new area is selected.

Pillar 1 testing includes NHS testing, such as tests of people being admitted to hospital or being discharged to a health/care home setting, pre-operative testing etc.

Pillar 2 testing is wider community testing

Lower tier authority cases

The next set of figures shows a quick glance of the lower tier local authorities within West Sussex. The black lines (shown on the actual numbers figures only) on each figure represent the rolling average number of new cases confirmed in the previous seven days.

You can toggle between looking at actual case numbers and rates of confirmed cases per 100,000 population.

Data source: https://coronavirus-staging.data.gov.uk

Given the differences in population sizes across West Sussex, you might naturally expect there to be more cases in one area than another. Viewing the cases per 100,000 allows you to compare across areas as if they had the same population size. We have used the mid year estimates for 2019 from the Office for National Statistics to calculate these rates.

Hover over a bar to see the number of new cases and cumulative cases to date.

It is important to check for any big spikes in the 'incomplete' period as these may not be highlighted by methods that exclude the last few days of data.

Number of tests and positivity

The majority of COVID-19 testing in the UK to date has been Polymerase chain reaction (PCR) testing which is lab-based and tests for the presence of SARS-CoV-2 virus (rather than testing for the body's immune response or antibodies). This data shows the number of people who received at least one PCR test in the previous 7 days, as well as the percentage of people who received a PCR test in the previous 7 days who had at least one positive PCR test result (the positivity rate). People are only counted once in a 7 day period.

Area PCR Positivity rate (weekly percentage of individuals tested who test positive for COVID-19)

Data source: https://coronavirus-staging.data.gov.uk

It is important to consider test positivity with caution and alongside the other measures such as confirmed case numbers and the information available on those being tested.

A higher percentage of positive tests could suggest higher transmission, and perhaps that there are likely more people with coronavirus in the community who have not been tested yet, which could further indicate a need for conducting a higher number of tests. However, it could also be that a change in positivity is related to different groups of people coming forward for testing. It is likely a mixture of several reasons.

Lateral flow device (LFD) virus tests are another type of COVID-19 test that look for the presence of SARS-CoV-2 virus. These are also swab tests, like the PCR tests, although they give results in less than an hour, without the need for laboratory processing. LFD tests are generally used for mass and routine testing of people who do not have COVID-19 symptoms. They are aimed at identifying individuals who may be infectious asymptomatic carriers and potential transmitters of the virus so these people can isolate and take the virus out of circulation in the community.

Age-specific rates of COVID-19 cases

The age distribution of confirmed COVID-19 cases is important as we have a good idea that whilst all age groups are susceptible to catching the virus, being older is thought to be a risk factor in becoming severely unwell with the virus.

We have seen from the national data that in the earlier waves of the pandemic, it was primarily older groups who were catching the virus, with a shift over the summer months to younger groups as more of society opened up and particularly as schools, colleges, and universities welcomed students back to classrooms.

From the end of October 2020, the UK government began publishing the number of confirmed COVID-19 cases by age group at local level. We have used these data to present a range of views of the age-specific confirmed transmission in West Sussex and other areas such as the South East region and England.

The first figure shows the 10 year age-specific rates over time in West Sussex. You can change the area using the drop down menu on the figure. Each line is coloured by age (see the key on the right). If you hover over a line or dot, the rest of the lines will fade and information about the number of cases and the age-specific rate (a method of standardising populations for comparison) at a given date.

Note that although we have tried to smooth out daily variation by using a rolling 7-day rate, at local levels when cases are still fairly low, there can be a lot of unsteady variation from day to day among some age groups. This can make the lines jump up and down. This is more so for lower tier areas and to a lesser extent for the county level. You may notice that the lines look much smoother at regional and national levels.

Area:

Data source: https://coronavirus-staging.data.gov.uk

Age bands

Age band key

There are similar patterns in the age-specific rates over time for West Sussex, South East region, and national data with rates among those aged 80+ far above other groups early in the pandemic. Following a dampening down of rates for all groups in the summer, younger cohorts rapidly exceeded the growth in cases of other groups from September onwards (potentially due to education settings but also likely due to hospitality venues such as bars and restaurants reopening).

It should also be considered that changes have occurred partly as test capacity and eligibility increased. Over time, more people were tested who were not displaying symptoms and these asymptomatic cases (perhaps picked up through workplace testing, or as a result of contact tracing) tended to be younger. It is possible that wider testing earlier in the pandemic may have identified many more younger aged cases of COVID-19.

Notwithstanding changes in testing, those aged 20-29 have continued to be key drivers of new infections in recent weeks and months whilst rates among 10-19's appear to be levelling off.

There has not been such a significant increase in infections among those aged 0-9 and the next figure shows a more detailed view of younger age groups. Again, you can change the area using the menu

The change in age-distribution of cases may be partly explained by different testing regimes with early testing only conducted among those who were symptomatic and often only among those who were hospitalised by the virus and as the testing capacity increased, more people were tested who did not have symptoms of a more severe illness.

Area:

Data source: https://coronavirus-staging.data.gov.uk

Age bands

Age band key

Rates across lower tier authority areas in England

The first figure in this section shows a scatter plot of every lower tier local authority in England represented by a dot with the most recent 7-day incidence rate per 100,000 population along the x axis (from left to right) and the percentage change in cases from the previous 7 days on the y axis (from bottom to top).

This figure uses a rate per 100,000 to standardise populations across areas (because some areas are much bigger or more densely populated than others) and using a rolling 7-day period helps to smooth out any large variation in daily cases due to operational issues such as test processing at weekends. This is useful for seeing the current picture (compared to other areas) and how the cases have changed over the recent past and if they are decreasing or increasing. You can use the slider to look at previous days going back to the start of September 2020.

The district and boroughs of West Sussex are highlighted here to make it easier to see local differences. The England rate is also highlighted in black. Hover over a dot to find out more.

Use the slider to choose a date (the most recent complete date is shown by default on the right)

Rates and change

The rolling 7 day total excludes the very recent few days as these are considered incomplete

The closer to the left of the chart an areas is, the lower the 7 day incidence rate, and the closer to the bottom of the chart, the smaller the change from the previous week. If the area is below the dashed line at 0%, the number of cases is decreasing compared to the previous week.

Data source: https://coronavirus-staging.data.gov.uk

Interpreting the percentage change value is actually easier if an area has at least some cases each week rather than having periods with no new cases. For example, an area with zero cases one week and two cases the next is perhaps better than having one case in one week and two in the next, yet the percentage increase is impossible to show from a starting value of zero. Equally, no change can mean two weeks of no new cases, or one case each week or 10.

Areas closest to the dashed line show stable levels of transmission, even if they are high.

Area key

The figure below shows the latest rates and change as a map, which you can zoom into using the mouse or pointer. The initial map shows the rolling 7-day incidence rate (up to the most recent date for which we believe we have complete data). You can change the map using the buttons on the top right to show the rolling 7-day total compared to the previous period as a percentage increase or decrease. Finally, you can look at the overall confirmed cases rate so far. It is important to consider each of these measures together; what are the cases now, what were the cases last week, how many cases have there been so far.

Data source: https://coronavirus-staging.data.gov.uk

Remember that the rolling 7 day total excludes the very recent few days as these are considered incomplete

What is a decile?

Every area in England is ranked from highest to lowest rate of confirmed COVID-19 cases per 100,000 population and then areas are divided into 10 groups each representing 10% of the areas in England.

Rates across upper tier authority areas in England

The next figure shows the rates and case changes but for upper tier local authority areas. The three Sussex Upper Tier and Unitary Local Authorities have been highlighted (see the key to the right) as well as England in black to show how local areas compare to other areas and the national picture. As before, you can change the date with the slider and hover over a dot to find out more.

Use the slider to choose a date (the most recent complete date is shown by default on the right)

Data source: https://coronavirus-staging.data.gov.uk

Area key

Data source: https://coronavirus-staging.data.gov.uk

Cases in your local area

Data on the number of new confirmed cases at a very localised area called an output area (Middle Layer Super Output Area, or MSOAs for short) is now available. This is useful as it means you can see what cases are like where you live or where your friends and family live. We do not get the same detail from the data published at this level compared to wider areas and when there are fewer than three cases in a seven day period in the MSOA, these are supressed.

However, you can search for a postcode in the box below for any postcode in England and a marker will appear on the map with more detail about cases in that local area.

MSOAs may vary in physical area size, but are design to cover roughly the same number of people (which is why there are many more MSOAs in towns and cities than there are in rural areas). Case data is supressed where an area has had fewer than 3 cases in the last seven days to prevent disclosure of any individuals identities.

Data source: https://coronavirus-staging.data.gov.uk

It should be noted that at a small area level (particularly at a local neighbourhood level such as MSOA) figures can fluctuate considerably from day to day and a small change in the number of cases (for example if a few large family groups test positive) this can have a big impact on the rates, so it is always worth considering not only your immediate area but the wider area when looking at the current situation and trends.

Cases in the latest 7 days

COVID-19 restrictions

On 4th January 2021, the Prime Minister announced a third national lockdown in England, issuing a stay at home message with education settings largely closed for face-to-face lessons to all except vulnerable children and children of critical workers

Further information is available on the Gov.uk website.

Deaths

The Office for National Statistics publishes weekly data at lower tier local authority for the number of deaths occurring in each week in the 2020 calendar year. From 31 March 2020 these figures also show the number of deaths involving coronavirus (COVID-19), based on any mention of COVID-19 on the death certificate. These are aggregated to upper tier local authority for this analysis.

Area:

Data source: Office for National Statistics

Data source: Office for National Statistics

The ONS weekly release of mortality at local authority level can be found here. Figures for previous weeks can be revised when new data are published to reflect more complete registrations.

Attributions

The data sources are given under each figure on this webpage but primarily come from UK Government for new case data, NHS Digital for NHS pathway contacts, and Office for National Statistics for data on mortality.

Data used in this analyses are primarily supplied under Open Government Licence and a number of supporting products such as geographical boundaries and postcode lookups have also been used.

The following copyright notices are applicable: