Weekly Update of England’s Coronavirus Figures: 29th March-4th April

This piece is part of a series of weekly blog posts that aim to summarise England’s progress throughout lockdown, showing (1) how far we have come; and (2) how far we could go if we maintain our current rates of decline. It provides an updated summary detailing the weekly change in:

  • Positive cases (by specimen date)
  • Hospital admissions
  • People in hospital with coronavirus (average across the week)
  • People on ventilation with coronavirus (average across the week)
  • Deaths (by date of death)
  • The cumulative number of people vaccinated (first and second dose separated)

Because of the data used, the weekly update will come in stages:

  • Monday – Vaccinations; people in hospital; and people on ventilation
  • Tuesday – Hospital admissions
  • Thursday – Cases (by specimen date)
  • Friday – Deaths (by date of death)

This is due to the length of time it takes for the each dataset to become complete. Some of the data takes longer (four to five days) because of using the specimen date for cases (the date the test was carried out rather than reported) and date of death for deaths (instead of date reported). The reasoning why these measures are used instead of the daily reported figures is because they give us a more accurate picture of what is happening in the community on any given day, whereas reported figures consistently oscillate between underreporting or overreporting infections and deaths, making it difficult to fully trust trends in its data.

WEEKLY UPDATE: 29th March-4th April

Summary:

  • The weekly number of positive cases decreased by 39.9% (from 30,377 cases to 18,269)
  • The weekly positivity rate for PCR tests decreased from 1.9% to 1.6%, meanwhile, the weekly positivity rate for LFD tests decreased from 0.25% to 0.18%
  • The weekly number of people admitted to hospital decreased by 30.7% (from 1,935 admissions to 1,341)
  • The average number of people in hospital with coronavirus per day this week decreased by 23.6% (from 3,906 people to 2,985)
  • The average number of people on ventilation with coronavirus per day this week decreased by 19.8% (from 590 people to 473)
  • The weekly number of people dying from coronavirus (28-day cut-off) decreased by 30.5% (from 259 people to 180 people*)
  • The cumulative number of people vaccinated with their first dose increased by 3.4% (from 25,903,782 people to 26,778,032)
  • The cumulative number of people vaccinated with their second dose increased by 55.2% (from 2,806,124 people to 4,355,141)

CASES

Here is a graph showing England’s weekly positive cases and where we could end up if we continue to follow our current trajectory:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 8th April)

The rate of decline accelerated significantly from -6.7% to -39.9% this week, meaning weekly case numbers fell from 30,377 to 18,269. We are now 95% down on January’s peak and 88% down on Lockdown 2.0’s peak. This is the biggest percentage decline England has seen since entering its third national lockdown at the beginning of January and should be viewed within the context of schools breaking up for Easter and the inclusion of the bank holiday weekend, which has significantly affected the number of tests carried out.

We can see this when delving deeper into the case data. Below is a graph detailing the weekly PCR and LFD test totals for England since mid-December, it shows that both PCR (down ~300k) and LFD (down ~1.5mill) tests have decreased significantly this week by ~1.8mill – a decrease of 30.8%. This makes it more difficult to compare case numbers to the previous three weeks as there is a big difference in the test numbers.

Data taken from Public Health England’s Weekly Surveillance Reports: https://www.gov.uk/government/statistics/national-flu-and-covid-19-surveillance-reports (April 9th edition)

However, this week’s test totals are similar to the week of 1st-7th March, making these two weeks a good point to compare case data from. We had 33,666 cases (by specimen date) then compared to 18,269 now, suggesting that the virus has still been declining in the past four weeks despite the full return of schools. It gives us an average weekly decline over the period of ~14%, which seems more likely than a massive drop this week.

This is reflected in the weekly PCR positivity rate as well, which has fallen from 2.5% (w/o 1st-7th March), to 2.4%, 2.0%, 1.9% and now 1.6%. Yet the same cannot be said for the weekly LFD positivity rate. At the beginning of March, it was 0.17% and has since bumped up from 0.15% to 0.19% and 0.25%, before coming back down to 0.18% this week. As the majority of LFD tests are carried out by schoolchildren and their families, this is perhaps not a surprise and certainly is not something to be worried out. But it is worth keeping an eye on when schools do go back after their Easter break.

Data taken from Public Health England’s Weekly Surveillance Reports: https://www.gov.uk/government/statistics/national-flu-and-covid-19-surveillance-reports (April 9th edition)

HOSPITAL ADMISSIONS

Here is a graph showing England’s weekly hospital admissions and where we could end up if we continue to follow our current trajectory:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 4th April)

The rate of decline accelerated significantly from -17.2% to -30.7% this week, meaning weekly hospital admissions decreased from 1,935 to 1,341. This puts us 95% down on January’s peak and 87% down on Lockdown 2.0’s peak. As numbers get lower, the rate is expectedly becoming more volatile so it is worth not reading too much into this anymore. The most important thing is that numbers are still declining. If we continue to follow our current trajectory, we would reach 644 weekly admissions by 12th April and 103 by 17th May. It means we are on course to reach the lowest levels achieved last summer by the week of 26th April-4th May.

PEOPLE IN HOSPITAL WITH CORONAVIRUS

Here is a graph showing the average number of people in hospital with coronavirus in England and where we could end up if we continue to follow our current trajectory:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 4th April)

This week the rate of decline decelerated ever so slightly from -24.1% to -23.6%, meaning the average number of people in hospital with coronavirus fell from 3,906 to 2,985. We are now 91% down on January’s peak and 79% down on Lockdown 2.0’s peak. It also means our projections remain essentially the same. If we continue falling at our current rate, we would see an average of 1,742 people in hospital by 12th April and we are still on course to reach the lowest levels we saw last summer by the week of 17th-23rd May, around the same time as Phase 3 reopening.

PEOPLE ON VENTILATION

Here is a graph showing the average number of people on ventilation per day with coronavirus and where we could end up if we continue to follow our current trajectory:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 4th April)

The rate of decline decelerated significantly from -26.3% to -19.8% this week, meaning the average number of people on ventilation with coronavirus fell from 590 to 473. We are now 87% down on January’s peak and 62% down on Lockdown 2.0’s peak. Again, numbers are getting so low now that we can expect the rate to be incredibly volatile from this point onwards. It does mean our projections looking forward have been pushed back though. If we continue falling at our current rate of decline, we would see an average of 304 people on ventilation by 12th April and 101 by 17th May. We also would not surpass the lowest levels achieved last summer until mid-June.

DEATHS

Here is a graph showing the weekly number of people dying from coronavirus in England within 28 days of a positive test (by date of death), and where we could end up if we continue to follow our current trajectory:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 9th April)

Before giving detail on this week’s numbers, I want to explain the difficulty of tracking deaths (by date of death). They are more time-lagged than cases, which means we tend to see a high number of revisions, even after the 4-5 days typically given to count the dataset as complete. Though it varies week-to-week, these revisions typically tend to be around 5-10% (range has increased since numbers are now incredibly small). To account for this, I create confidence intervals based on 5-10% of the weekly total (as of 9th April) and then use the middle figure to calculate the week-on-week percentage change. This means that deaths are more of an estimate than the others, but it is accurate enough to gauge how well we are doing.

The weekly total of deaths for 29th March-4th April currently stands at 168, giving us a 5-10% confidence range of 176-184. The middle point, 180 deaths, means the rate of decline has decelerated from -42.4% to -30.5%. This rate is incredibly volatile now since numbers are so small, making the rate of decline less important than the fact numbers are still declining. We are now 97.3% down on January’s peak and 93.3% down on Lockdown 2.0’s peak. At our current rate of decline, we would surpass the lowest levels reached last summer by the week of 26th April-2nd May.

VACCINATIONS

Here is a graph showing the weekly number of vaccinations carried out in England, first and second doses separately:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 4th April)

Here is a graph showing the culminative number of people vaccinated with their first dose in England and where we could end up if we continue to follow our current trajectory:

Data taken from the UK Government’s COVID-19 Dashboard: https://coronavirus.data.gov.uk/ (accurate to 4th April)

In the week of 29th March-4th April, England administered 874,250 first doses and 1,549,017 second doses of the coronavirus vaccine. This represents a ~1.2 million decrease in first doses and a ~400k increase in second doses from last week’s totals. It brings our cumulative totals up to ~26.8m for first doses and ~4.36m for second doses – an increase of 3.4% and 55.2% respectively.

This is the first week since the end of December where the weekly amount of second doses exceeded that of first doses. We can expect this trend to continue over the next few weeks to accommodate the vast number of people who are now in need of their second dose. However, the number of first doses administered was particularly on the low side this week. It could be due to the bank holiday weekend and also supply constraints. Yet it would be good if we can get this figure back over 1 million so that we can continue vaccinating the rest of the population at a good pace.

Due to the unreliability in doses to be administered, it makes projecting very difficult. It was thought that we would have surpassed the government’s second target of the first nine priority groups vaccinated (~27m) during the week of 29th March-4th April, but we have fallen just short. Nonetheless, we should achieve this the week after the Easter bank holiday, which does not delay things too much and will now mean we can focus on vaccinating the non-priority groups ahead of summer.

Previous Weekly Updates

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