Weekly Update of England’s Coronavirus Figures: 15th-21st March

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: 15th-21st March

Summary:

  • The weekly number of people testing positive decreased by 2.0% (from 32,932 people to 32,260)
  • The weekly positivity rate for PCR tests decreased from 2.4% to 2.1%, meanwhile, the weekly positivity rate for LFD tests increased from 0.15% to 0.19%
  • The weekly number of people admitted to hospital decreased by 23.5% (from 3,055 admissions to 2,338)
  • The average number of people in hospital with coronavirus per day this week decreased by 24.1% (down from 6,780 people to 5,149)
  • The average number of people on ventilation with coronavirus per day this week decreased by 26.6% (down from 1,092 people to 801)
  • The weekly number of people dying from coronavirus (28-day cut-off) decreased by 35.2%% (from 682 people to 442*)
  • The cumulative number of people vaccinated with their first dose increased by 14.7% (from 20,791,838 people to 23,854,862)
  • The cumulative number of people vaccinated with their second dose increased by 43.6% (from 1,129,444 people to 1,621,547)

CASES & POSITIVITY RATE

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 23rd March)

The rate of decline has plateaued at -2.0% this week, meaning weekly case numbers only fell from 32,932 to 32,260. This puts us 91% down on January’s peak and 79% down on Lockdown 2.0’s peak. The flatlining of cases is not a worry for the moment though because we are still adjusting to conducting mass testing in schools and other settings.

This week saw a similar number of tests carried out for both PCR and LFD tests, which means we can draw more accurate conclusions than in recent weeks. The weekly positivity rates for both PCR tests and LFD tests is shown in the graph below. While PCR tests saw a decent decline in positivity from -2.4% to -2.1%, LFD tests saw an marginal increase from 0.15% to 0.19%. We should feel encouraged by the drop in positivity for PCR tests though and I don’t think the increase in LFD positivity is anything to be worried about at the moment given how marginal it was.

However, it will be important to check whether this flatlining of cases affects hospital figures or deaths moving forward. At the moment, they are not having a slowing effect elsewhere – which is good news re. vaccines – but we will need to keep an eye on this over the next few weeks.

Data taken from Public Health England’s Weekly Surveillance Reports: https://www.gov.uk/government/statistics/national-flu-and-covid-19-surveillance-reports (March 25th 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 23rd March)

The rate of decline decelerated slightly from -24.9% to -23.5% this week, meaning weekly hospital admissions decreased from 3,055 to 2,338. This puts us 91% down on January’s peak and 78% down on Lockdown 2.0’s peak. This deceleration slows down our projections for Phase 1B, 2 and 3 relaxations too. If we continue to follow our current trajectory, we would reach 1,368 weekly admissions by 29th March and 801 weekly admissions by 12th April. However, we would still be on course to reach the lowest levels we achieved last summer by the week of 10th-16th May – one week before Phase 3 of England’s lockdown exit is due to commence.

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 22nd March)

This week the rate of decline decelerated slightly from -25.8% to -24.1%, meaning the average number of people in hospital with coronavirus fell from 6,780 to 5,149. We are now 85% down on January’s peak and 64% down on Lockdown 2.0’s peak. The slightly slower decline pushes are projections back a bit too. If we continue falling at our current rate, we would see an average of 2,966 people in hospital by 29th March and 1,709 people by 12th April. However, we would be on course to reach the lowest levels we saw last summer by 17th May, around the same time as the 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 22nd March)

The rate of decline accelerated from -25.0% to -26.6% this week, meaning the average number of people on ventilation with coronavirus fell from 1,092 to 801. This is the first time we have fallen below 1,000 since early November. We are now 78% down on January’s peak and 36% down on Lockdown 2.0’s peak. The rate acceleration has improved our projections looking forward too. By 29th March, we could see an average of 432 people on ventilation, meanwhile, by 12th April, we could see this number falling to 232. As ever, these projections are contingent on us falling at our current rate of decline. Moreover, we are on course to reach the lowest levels we saw last summer by 17th May – the same time as hospitalisations.

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 26th March)

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 5-7.5%. To account for this, I create confidence intervals based on 5-7.5% of the weekly total (as of 26th March) 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 15th-21st March currently stands at 416, giving us a 5-7.5% confidence range of 437-447. The middle point, 442 deaths, means the rate of decline is -35.2%, an acceleration on last week’s -31.3%. We are now 94% down on January’s peak and 84% 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 19th-25th April.

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 22nd March)

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 22nd March)

In the week of 15th-21st March, England administered 3,063,024 first doses and 492,103 second doses of the coronavirus vaccine. This represents a significant increase on last week’s totals, up from ~1.8m and ~300k respectively. It took our cumulative totals up to ~23.9m for first doses and ~1.62m for second doses – an increase of 14.7% and 43.6% respectively. The figures for this week finally represent the ramp-up in supply that ministers have been promising for weeks now.

Nonetheless, recent news suggests a constriction in the supply chains for April, which will affect our ability to continue administering first doses at pace while accommodating the significant proportion of second doses. This means that the ~3m total of first doses we have seen this week is unsustainable and will drop back down over the next few weeks.

Due to the unreliability in doses to be administered, it makes projecting very difficult. It looks like we will have no problem reaching the second government target of the first nine priority groups vaccinated (~27m) sometime during the week of 22nd-28th March. However, how quickly we can now vaccinate the non-priority groups given our supply constraints is more uncertain.

PREVIOUS WEEKLY UPDATES

Week 1: 25th-31st January

Week 2: 1st-7th February

Week 3: 8th-14th February

Week 4: 15th-21st February

Week 5: 22nd-28th February

Week 6: 1st-7th March

Week 7: 8th-14th March

2 thoughts on “Weekly Update of England’s Coronavirus Figures: 15th-21st March

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