Category: COVID19

The variant of concern

April 13th, 2021. Go to post.

The sun is shining as the UK comes out of its winter hibernation lockdown after a traumatic winter. Yet, despite a hugely successful vaccination campaign and a massive increase in testing, many people remain deeply concerned. Most of this concern surrounds variants to the Wild Type – the strain of the COVID-19 virus with no significant mutations.

There is good reason to be concerned about variants (“Variants of Concern”). The second wave of COVID-19 in the UK has been dominated by the B117 variant, which appears to have originated in Kent. Unlike the Wild Type, B117 is both more transmissible and causes more severe illness. In numbers:

  • without social distancing, each person infected with B117 is likely to infect 3-4 other people compared to 2-3 others for the Wild Type
  • for every 100 +80 years olds infected with B117, 82 will become critically ill, and 16 are likely to die compared to 50 and 10 for the Wild Type

More cases and more critically ill people means more pressure on the NHS, which has triggered the need for both of the major national lockdowns.

The positive news is that the first generation of COVID-19 vaccines is effective at reducing both:

  • people getting infected, which means they won’t get sick or pass on the virus to others; and
  • people becoming critically ill or dying if they do get infected

These effects are good since they mean the risk of a third wave of COVID-19 is reduced, and the impact on the NHS is also reduced. Provided the UK continues its heroic vaccine rollout, and there is some social distancing over the next few months, we should see B117 pushed into submission – just don’t plan on going to any big events.

Given that the B117 variant of COVID-19 is widespread in the UK and under some control, it is not a concern. So how much should we be concerned about other “variants”?

Since the pandemic started, there have been over 137 million reported cases of COVID-19 (certainly a vast underestimate of total actual cases). From this massive number of infections, there have been around 4,000 variants identified. Of these 4,000, only four are currently recognised as Variants of Concern in the UK (four more variants are “under investigation”). Two of these Variants of Concern are homegrown – B117 and B117 with the E484K mutation.*

The two other Variants of Concern are B1351 (South Africa) and P1 (Brazil). Much less evidence is available on these variants – this uncertainty in and of itself creates concern. But at the moment, neither of these variants appears more transmissible nor more deadly than B117. Current evidence also suggests that vaccinations effectively reduce the number of people who get critically ill or die after becoming infected with either of these variants. This impact is tentatively good news – see chart below, which is based on our modelling of the vaccine rollout and current evidence of the different variants.

Based on this evidence, some will conclude the pandemic is over. But for B1351, there is some early evidence to suggest that it can evade vaccinations and still infect people. This ability is terrible since it means the variant could spread through a vaccinated population as social distancing measures are relaxed. Even though fewer people would get critically sick for the same number of infections, there could be a large number of infections (remember that exponential growth quickly makes small numbers very large). The chart below shows this graphically for infectiousness (R0) and the impact of vaccinations – only the B1351 variant sits in the amber zone, meaning it may still spread after the vaccination programme.

The ability to evade vaccines is likely the main reason for surge testing in Lambeth and Wandsworth following an outbreak of at least 44 cases of B1351 at a care home.

The next few weeks will be critical for understanding B1351 in greater depth, specifically on how much it evades the current generation of vaccinations. It will also be essential in seeing how it progresses in the battle for COVID-19 dominance, which as the chart below shows, is a race currently being won by B117 (Kent).

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Published 14 April 2021

* Some may be interested in whether we should be worried about other new variants. Without going into the genealogy (not my area) too much, there are a limited number of mutations that can benefit the SARS-CoV-2 virus. Consequently, as I understand there is likely to be a high degree of convergent evolution – this is why we have only variants coalescing around the same mutations.

Study: Safe list could be more than doubled with no increase in risk, due to UK vaccinations

March 30th, 2021. Go to post.

Posted 25/03/2021

  • Travel corridors could mean that more than 100 countries would open up to UK visitors with no increased risk, if case rates are similar to last summer
  • If high-performing antigen tests are administered pre-departure, the list could increase to more than 130 with the same level of accepted risk
  • UK’s successful vaccine roll-out means British travellers could visit countries with prevalence rates three times higher than in 2020 without increasing infection rate in the UK community upon their return
  • Findings come as the UK government considers the reopening of international travel from May 17 with a suggested tiered approach to managing risk

The success of the UK’s vaccination programme means the number of countries on the travel ‘green list’, could be more than doubled without putting public health at risk, research ahead of the Government’s Global Travel Taskforce report shows.

A study carried out by Edge Health and Oxera for Manchester Airports Group shows that if case rates this summer are similar to last year, passengers could start travelling to more than 130 countries such as Spain, the United States, and Dubai.

The study looks at the risk of new infections from July and August 2020, when the travel corridor scheme allowed people to visit countries in which rates were below a certain threshold.

The Edge Health and Oxera modelling shows that because of the extent of the UK’s vaccination roll-out, travellers from the UK could now visit overseas destinations with virus prevalence rates three times higher than they were in 2020, without increasing the risk or putting pressure on the NHS.

This is because vaccinations increase immunity in the population, drastically reducing severe illness and also leading to a lower rate of transmission (R number).

If the vaccines had been available in 2020 this would have safely increased the number of countries on the list from 62 to 102.

If pre-departure high-performing antigen tests are administered, prevalence could increase by a factor of six to eight with no further impact to risk.

That would mean almost 30 additional countries could be added to the list, letting passengers travel safely to up to 91% of all countries.

When vaccination programmes in other countries outside of the UK and the vaccination of those aged 17 and below is taken into consideration, the number of possible destinations could rise even further.

The study has been combined with data that shows the success of the UK’s vaccination programme has led to a significant reduction in hospitalisations and deaths from COVID-19. This demonstrates that an increase in the number of ‘green list’ countries is possible whilst maintaining the low levels of new infections observed in Summer 2020.

Edge Health and Oxera’s and study is based on a list of the 143 countries where estimates of COVID-19 prevalence are available and includes the top ten destinations for passengers from the UK.

George Batchelor, Cofounder and Director of Edge Health, said:

‘The greater the number of people who are vaccinated, the more the public health dangers posed COVID-19 decline.’

‘Although the risk of variants remain a concern none have yet become dominant over the wild type of SARS-CoV-2 globally. In the UK, where the dominant variant is now B117 (Kent), vaccines have been shown to be effective which means we can be cautiously optimistic. This means international travel can be safely restarted if travel policies, such as testing, are targeted at countries with greater levels of risk. To the extent that other variants need to be treated carefully in coming months as we learn more about their characteristics, it is important to remember that many of them are already present in the community.

Michele Granatstein, Partner at Oxera and Head of its Aviation practice, said:

‘The successful rollout of the UK’s vaccination programme, with 32m people having received a first dose, is crucial to the safe re-opening of air travel. The vaccines’ role in significantly reducing not only the number of hospitalisations and COVID-19 deaths but transmission rates of the virus should give assurance that safe travel to international destinations is within reach.’

‘Given these promising results, the proposed green list countries could safely be extended this summer.’

‘Extending the travel corridor scheme would also give people greater peace of mind that they can travel safely, while removing the obligation to undergo an inconvenient and potentially expensive quarantine period.’

Charlie Cornish, Group CEO of Manchester Airports Group, said:

‘Throughout this pandemic, MAG and the wider travel industry has supported the need for strict measures to prevent the spread of the virus and respond to new variants.’

‘At the same time, the case for restarting international travel safely and at the earliest opportunity is clear. Hundreds of thousands of jobs and billions of pounds-worth of economic value hang in the balance, while families are desperate for a hard-earned holiday, or to be reunited with loved ones they have been separated from during the most challenging of years.’

‘The Government’s vaccination programme is the envy of the world and this study shows that unlocking travel to a wide range of destinations is one of the many ways in which the British public can benefit from its success.’

‘This research is a hugely valuable contribution to the work of the Global Travel Taskforce and paves the way for overseas travel to resume as soon as possible.’

‘We look forward to continuing to work with the Taskforce ahead of the publication of its framework next week, and to playing our part in getting Britain flying again and driving our recovery from this pandemic.’

Contact: George Batchelor

Posted 25/03/2021

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Study: Single COVID-19 test on arrival as effective as ten-day quarantine

March 25th, 2021. Go to post.

Posted 25/03/2021

A single on-arrival antigen test is as effective as a ten-day self-isolation period in reducing imported cases of COVID-19, new modelling has revealed. Based on prevalence rates at home and abroad and accounting for quarantine compliance, Edge Health and Oxera find that a single rapid antigen test would be appropriate for arrivals from the majority of countries categorised as medium risk, where there are medium caseloads or lower vaccination rates. Such countries could be designated as ‘amber’ if the UK Government applies a traffic light system for foreign travel to categorise risk.

In evidence submitted to the UK government’s Global Travel Taskforce this week, many of the quick, inexpensive and effective antigen tests are shown to reduce the number of infectious days of an international arrival by 63%. This means that the risk of community transmission from a single test is comparable, if not more effective, to a ten-day quarantine period with no testing, which screens 62% of infectious days and was the UK border policy for countries without travel corridors until 18 January 2021.

The new findings demonstrate how the government’s evidence base has underestimated the effectiveness of a single antigen test, which SAGE previously reported would screen only 11% of infectious travellers.

For higher-risk countries, a two-test strategy could be a viable option as part of a risk-based framework to safely reopen international travel this summer. Using a 72-hour pre-departure antigen test and three-day quarantine with PCR test, 87% of potentially infectious days are screened—just one percentage point lower than a dual-PCR test. Crucially, the new evidence demonstrates that the two-test approach delivers effective levels of screening, while ensuring that the UK can easily track and genome sequence the tests of passengers, mitigating the risk of importing variants of concern.

The government currently mandates a pre-departure test within 72 hours of travel to England and managed quarantine in a hotel for ten days with two PCR tests for anyone arriving from a red list country, at a cost of £1,750. Arrivals from all other countries must quarantine at home for ten days and purchase a £210 travel test package with two PCR tests, for administration on days two and eight of self-isolation.

George Batchelor, Cofounder and Director of Edge Health, said:

‘When the skies reopen, it’s clear that a proportionate COVID-19 testing regime will remain an effective line of defence to support international travel to and from the UK.’

‘Given the success of the UK vaccination programme, and in line with the UK government’s risk-based approach to the wider economy, any restrictions should be targeted at reducing the potential import of variants of concern. Our modelling demonstrates that a single antigen test for medium-risk countries and dual-test approach for higher risk countries, combined with three-day quarantine, could be an effective strategy to protect public health, while removing the burden of a ten-day quarantine.’

Michele Granatstein, Partner at Oxera and Head of its Aviation practice, said:

‘The ultimate goal for governments must be to return to frictionless travel between countries that are considered lower-risk. The vaccine roll-out, combined with internationally agreed standards on digital solutions to evidence COVID-status certification, will be intrinsic to that, but people should be able to travel safely, with or without a vaccine.

‘Our analysis of the effectiveness of different quarantine and testing strategies shows that the UK government can safely restart international travel at scale while tailoring test requirements and restrictions on a country-by-country basis.’

Comparison of dual- and single-testing schemes finds only a marginal benefit, with the two-test approach screening just 5–9% of additional infectious days compared to one test. For example, a single antigen test administered on departure screens 62% of infectious days, while two antigen tests, one administered 72 hours before departure and another on departure, screen 67% of infectious days.

Using 2020–21 data from the USA and the EU, the report also finds that even when COVID-19 prevalence has been higher than the UK, arriving air passengers contribute fewer potentially infectious days into the community per capita compared to domestic infections.

Based on real-world data from 14 December 2020, when prevalence in the USA was the highest that it has been relative to the UK, 10,000 incoming air passengers would have had 79% fewer infectious days than 10,000 individuals in the UK community if a single on-departure antigen test had been administered. The relative risk of importing infections is also expected to decrease further as vaccinations are rolled out domestically and internationally. Around 31 million total Covid-19 vaccine doses have now been administered in the UK, with more than half of adults receiving a first dose.

The report has been submitted to the UK government’s Global Travel Taskforce to inform its new risk-based framework to facilitate international travel.

Contact: George Batchelor

Posted 25/03/2021

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The roadmap should be transparently and explicitly linked to data

February 25th, 2021. Go to post.

The much-anticipated roadmap out of lockdown was announced and published on Monday. While the prospect of heading to the disco on 21 June is exciting, the focus on dates, as opposed to data, was a shame.

Also disappointed was the Tony Blair Institute. Their “lockdown lessons” paper, published last week, had suggested explicitly linking the easing, or tightening, of restrictions to the data. They proposed a framework for linked tiers and alerts to triggers – see image below.

While basic (no account for NHS capacity or vaccination efforts), it seems like a good start.

There are many scientific nuances to consider before removing restrictions, but not having an open and transparent framework linked explicitly to public data is more than just a shame. Explicit measures set expectations that reinforce the intended outcome. They avoid “the politics” taking control of what should be rational decisions. A bit like how inflation-targeting by the Bank of England helped remove destabilising inflation.

To see how a framework might have helped, the chart below shows infection rates per 100,000 over the past few months mapped to the TBI’s proposed framework. Level 1 is noticeably not reached – even in the summer. Also noticeable is the delay in ramping up restrictions in mid-December.

Would decision-makers have been happier to ramp up restrictions before Christmas if there had been agreed trigger points based on public data? Would knowing the direction of travel of case numbers have led to more cautious behaviour in the population? Would being more cautious have helped stop the need for additional restrictions?

We may never know what might have happened if Lockdown 3 had started in mid-December. Perhaps we would be a nation of rulebreakers! Equally, the modelling that we did for the Telegraph in December suggested that a proper pre-Christmas lockdown could have led to only 6,300 deaths in January – significantly lower than the ~28,000 actual deaths in January.*

Looking forward, based on the current rate of transmission (with a slight uplift for schools returning), we have mapped the expected case rate onto the case rate framework – see chart below. This chart shows the dates when our data suggest the Government could reduce the restrictions (e.g. hospitality open from 30 April).

There is some alignment between these data dates and the first two steps of the Government’s plan. It is also doubtful that there isn’t a huge amount of modelling behind the proposed dates. So why the apparent secrecy or lack of willingness to provide a more transparent framework ahead of time?

The vaccination programme’s success is something to be optimistic about, and the TBI framework doesn’t explicitly take this into account.** It may also just be me, but I feel conditioned to expect the worst from this pandemic and its lockdown dancing partner. Perhaps the vaccination programme will be like the awkward friend that sends you home early from the disco, but indeed there are still reasons to be a bit cautious on the dancefloor?

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Published 26 February 2021

* Deaths are modelled weekly, so these numbers will not align perfectly. It is important to note that our projections were significantly lower than 28,000, possibly due to more mixing than expected and the highly transmissible B117 variant even in our worst-case scenario.
** Success with the vaccinations would, of course, reduce the amount of transmission, so would reduce case numbers.

What’s next for the NHS?

February 16th, 2021. Go to post.

Building the resilience of the health and care system

Press release – embargoed to 0001 Wednesday 17 February 2020

One in six could be on an NHS waitlist by April

  • Waitlists in England to hit 10 million by April
  • 52 week waits up 12,008% by April since March 2020
  • 6 million fewer referrals to treatment in 2020 as NHS became National COVID Service
  • 1,660 extra lung cancer deaths alone due to delays

Despite the heroic efforts of healthcare leaders and frontline workers, a lack of system resilience forced the NHS to become a National COVID Service, a report says.

New modelling projects that waiting lists could hit 10 million by April, equivalent to one in six in England, according to new research by independent think tank Reform and Edge Health.

By April, the number of people waiting a year or more for care is expected to have risen 12,008% since the start of the pandemic in March 2020 – by December, the latest month for which there is data, it had already risen by 7,139%.

5,948,000 fewer referrals to treatment were made in 2020 compared to 2019 as the pandemic took hold.

The modelling projects that waiting lists could hit 10 million by April, equivalent to one in six in England, as referrals for non-COVID begin to restart whilst pandemic pressure and infection prevention measures still limit NHS capacity. This is a conservative estimate as data for December and January, when routine care was again cancelled, is not yet available.

Tragically, for lung cancer alone 1,660 premature deaths are expected due to delayed diagnosis and treatment, the paper predicts.

George Batchelor, Director, Edge Health, said:

“The ferocity of the pandemic was met with tremendous bravery but came at a cost to normal NHS services, which in many areas were struggling before the pandemic. The full scale of this cost has not yet been seen, but the backlog is already ballooning and will get much worse in coming months.

“The short-term recovery of NHS staff will jar with the need to manage the backlog. But perhaps a bigger challenge will be how to balance the recovery while also building greater long-term resilience and preparedness for the future.”


For more information or to arrange an interview with George  please contact us on [email protected] or 020 8133 4504.

Notes to editors

1. Reform is an independent, non-party, charitable think tank whose mission is to set out ideas that will improve public services for all and deliver value for money.

2. Edge Health is a specialist firm that provides tailored health data analytics and insights to organisations.

3. Download the full report here.

4. ‘What’s next for the NHS’ is authored by Eleonora Harwich, Matthew Fetzer, Sebastian Rees, George Batchelor, Jennifer Connolly and Maria Starovoitova.

5. “New modelling projects that waiting lists for care could hit 10 million by April 2021” – see Figure 5 on page 14. Headline line number is calculated by dividing worse-case scenario waitlist projection by population size. Further details:

· The projections are based on the proportion of ‘missing’ activity that returns over the next few months and assuming lower NHS productivity due to infection control measures. This missing activity corresponds to the difference between the number of referral in 2019 and those in 2020. There were 5,948,000 fewer referrals in 2020 than in 2019.

· The projections assume that there is a gradual return to normal levels of referrals by GPs by March 2021 and assumes gradual return to normal treatment volumes considering COVID-19 safety measures by March 2021.

· Under the worst-case scenario, the official NHS waiting list grows to over 10 million by April 2021.

6. “By April, the number of people waiting a year or more for care is expected to have risen 12,008% since the start of the pandemic in March 2020 – by December, the latest month for which there is data, it had already risen by 7,139%” – please see Figure 3 on Page 13. A linear model was fitted to data from March 2020 until December 2020 describing the following relationship y = x + x^2 with x being the number of people waiting 52 weeks on the waiting list in a given month. The model perfectly described the rate of increase in the 52-weeks + waiting list category and was therefore projected forward until April 2021 to find the number of people who would be waiting for more 52 weeks or more by April 2021.

7. “5,948,000 fewer referrals to treatment .” – see Figure 4 on page 13.

8. “1,660 extra lung cancer deaths” – see Appendix on page 36 – 37 for methodology

9. “The findings come as NHS officials last week warned that extended waits for treatment can be expected “for some years”.” – see NHS Confederation letter here.

10. “Modelling identified that around 141,808 worth of hospital ‘bed-days could have been freed up during the April 2020 peak, had delayed discharges and hospital overstays been avoided.” – see Figure 10 on page 27.

11. “Calls made by NHS Confederation to increase bed capacity in acute services would not be the correct response” – response to NHS Confederation letter here. Refers to the first bullet point on page 3 which lists a number of recommendations to tackle the impact of the pandemic on the NHS, including additional investment in acute services to increase bed capacity.

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Published 17 February 2021

Injecting some positivity

February 15th, 2021. Go to post.

Published 15 February 2021

It has been a reasonably gloomy few months, but yesterday was a day to be… more positive. Edge turned four, and data continued to emerge on the success of the vaccine programme.

When Ed and I started working together a little over 16-years ago, we did not expect to start Edge. And when we began Edge four years ago with Christian, we did not expect a pandemic – although we were the first to publicly quantify its possibly devastating impact on the NHS (read more on the impact of Edge at four here).

The last year has been challenging on several levels, and it is hard not to doomcast the next problem, but this has started to change with the vaccinations. A number of the vaccine candidates achieved tremendous levels of efficacy in trials and got regulatory approvals.

Over 15 million jabs later and we are starting to see the effectiveness of the vaccine programme in the UK in the data – see orange ring in the chart below.

Since the week ending 30th of January, Covid-19 deaths in people aged over 80 (a priority group for vaccination) have fallen by 48%, compared to 39% in those under 80. To put it another way, deaths in the older age group have fallen 25% more quickly. It is this relative fall in Covid-19 deaths in people aged over 80 which can be seen in the chart above.

Data sceptics will argue there is a lot of noise in the data, and it is still too early to draw any firm conclusions. This is partially true, but we forecast and expected the current drop just over three weeks ago based on vaccination policy. This forecast now seems to be showing in the data, which lines up with evidence from other countries that are further ahead with their vaccine programmes, such as Israel.

There is still a lot to be done on the vaccination programme, and the pandemic is far from over. Yet, it cannot be overstated how lucky we are that the vaccination is so effective – seasonal flu vaccines are routinely around only 50% effective.

Hopefully next year it will be safe to celebrate Edge turning five in-person! In the meantime, you can read about the work we are most proud of from the last four years here.

When will we see the effect of the vaccination programme?

January 21st, 2021. Go to post.

Published 21 January 2021

An impressive 5 million people have now had their first shot of a vaccine in the UK. With around 350,000 vaccinations per day, the UK will be vaccinating over 2 million people per week – arguably ahead of expectations. But when will we start to see the effect of this enormous effort and what might we expect?

Vaccinations rates have increased steadily over the past few weeks focusing priority groups – care home residents and workers, over 80s, health and social care workers, over 70s, and the extremely vulnerable under 70s.

Prioritising the vaccine in the over 80s who have a higher mortality rate for Covid-19 means that we should start to see a drop in the proportion of deaths accounted for by this group first. The chart below shows this % over time, along with the total reported daily deaths.

There are not yet any discernible downward trends in either data, but this is to be expected. Once vaccinated there are around 14 days before there is protection. Combined with low vaccination rates in December, and an average 17-day delay between infection and death, we would not expect to see the benefit of vaccinations until mid-February. Expect lots of data watching!

There are many reasons that the benefit will be hard to see or smaller than hoped (and why test and trace really is still critical). These include factors, such as vaccine rates that are higher in groups of people who are less likely to be exposed to risk or are lower risk. There are also differences in local area vaccination rates and some worrying evidence from Israel that the one dose strategy (with second to follow) does not deliver as much benefit as hoped. And this is before considering the possibility that the vaccine will be slightly less effective against new variants.

Given the importance of the vaccination programme for removing the lockdown, it is critical to have good data. While headline vaccination rates are great, they do not tell the full story of the people offered or who is declining/receiving the vaccinations, and where they are based. These data will be critical. Pre-empting this, Ed Humperson from the Statistics Regulator has written to the UK Government requesting this additional information – read more here.

Fingers crossed!

As many as 1 in 5 people in England have had the Covid-19 disease

January 11th, 2021. Go to post.

Published 11 January 2021


  • In England, as many as 1 in 5 people, or 12.4 million, are estimated to have had the Covid-19 disease
  • The estimate is substantially higher than the 2.4 million confirmed cases from Public Health England, which is based on reported tests alone
  • The new modelling estimates the total number of cases in an area by comparing its number of deaths against an estimated infection fatality rate (IFR) – for more recent weeks data are based on extrapolations from reported case rates
  • The modelling shows substantial regional variations with over 50% of the population of Barking and Dagenham having had Covid-19 compared to less than 5% in Cornwall

New research suggests as many as 1 in 5 people, or 12.4 million, in England have had Covid-19. This is significantly higher than the 2.4 million reported cases from Public Health England (PHE). There is also substantial variation between local authorities (UTLAs) with 54.2% of Barking and Dagenham having had Covid-19 than 4.8% in Cornwall.

This reflects several difficult and challenging weeks where new infections have increased substantially. Up to the week of 7th of December 2020, an estimated 18% of people in England have had Covid-19 – up to 22% by the week commencing 28th of December 2020. The estimates are compatible with the most recent estimates of active infections in the community from the Office for National Statistics (ONS) Infection Survey[1,2]. The estimates model the population thought to have had Covid-19 since the beginning of the pandemic – they may differ slightly from antibody studies, as people who were infected with Covid-19 may lose antibodies over time.[3]

Total cases are estimated by looking at each local authority’s (UTLA’s) Covid-19-related deaths as published by the ONS and their estimated infection fatality ratio (IFR).

The IFR is calculated by looking at a local authority’s age profile and applying age-specific infection fatality ratios from University of Cambridge research [4]. These infection fatality rates are slightly lower for the second wave.

For more recent weeks, case numbers are estimated by extrapolating case numbers from PHE confirmed cases using the historical ratio of cases to PHE confirmed cases. Extrapolating cases in this way will be sensitive to changes in testing behaviour and capacity so should be interpreted with these caveats. Since cases are extrapolated at the local authority level, there are sometimes small sample sizes when calculating the ratio – for this reason, three months of testing data is used for estimating the rates.

George Batchelor, Cofounder and Director of Edge Health, said:

“Reported tests are only a fraction of the picture of total infections, which show how badly hit London and the north-west have been during the pandemic. It is incredible that the level of understanding of where and how infections are occurring is not greater at this stage, since it would allow control measures to be more targeted.

“Even with imminent vaccinations, it is crucial to develop this understanding so that future variants of the virus can be effectively controlled and managed.”

Jennifer Connolly, Consultant at Edge Health and lead analyst for the work, said:

“This modelling work allows us to draw a fair comparison between the current wave and the first wave in Spring, even though testing capacity has changed significantly. Our most recent estimates are currently projecting the highest numbers of new cases since the Spring. This is particularly the case in boroughs in and around London.

Detailed information, including data

Click the link below for detailed methodology and data.

About Edge Health

Edge Health is a firm that specialises in helping organisations to deliver better health and care outcomes by creating better analytics and insights from their data. This work ranges from consultancy through to the development of bespoke data products.

Established in 2017, Edge Health is a firm composed of economists and data scientists who have worked extensively with the NHS as well as local government, private and independent organisations.


George Batchelor



[3] If people test positive for Covid-19 for two weeks during their infection and an equal number of people are recovering and getting newly infected, our analysis would be equivalent to roughly +3% new cases over three weeks.


How many people have had Covid-19?

January 11th, 2021. Go to post.

Published 12 January 2021

Our new research, which we did for the Guardian, estimates that 1 in 5 people in England has had Covid-19. Since the start of the pandemic, that is about 12.4 million people – see grey bars in the chart below.

The numbers are substantially higher than the 2.4 million confirmed infections from PHE testing (see red bars in the chart above), which has grown significantly since the spring. Our estimate of total cases is calculated by looking at a local authority’s age profile and applying age-specific infection fatality ratios – adjusted for the second wave (due to improvements in treatment).

There is substantial variation across local authorities with Barking and Dagenham being as high as 54% and Cornwall being as low as 4.8%. This infection level reflects London being hit – by surprise (twice) – in both the first and second (mutant) wave of Covid-19.

Perhaps the most startling finding is that almost half (49%) of these infections are estimated to have happened since the end of the first national lockdown. This suggests that, aside from draconian lockdowns, the measures to control spread could be better understood and implemented. This would be helped with more information on where and why the spread is happening (non-compliant birthday celebrations, lessons in Victorian school classrooms, car sharing, coffee in the park, bits of all of the above, etc.).

Unfortunately, this increase in cases translates into more occupied hospital beds – now at critically high levels. The horrifying milestone of critical care bed occupancy from the 10th of April (1,057) was hit in London today and will only get worse for the next few days. Nationally there are now 3,055 in critical care – also higher than the first wave. (Excellent article from the Global Health Security Team in the Telegraph on this here.)

This is unimaginably given how much more is known about Covid-19 this time.

Relying on the vaccines alone to protect the NHS, and end lockdowns is not enough. And, if it is, what happens if the vaccine for the next pandemic doesn’t work as effectively? More needs to be done to understand how and where infections are happening so that control measures can be less draconian. This is unlikely to stop being important even after we have all had our vaccination.

Read more about our work on total infections here (you can even download the detailed data):

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[*] Any suggestion that these numbers take us close to herd immunity need to remember that it would require redoing 2020 at least three more times – possibly more if you can catch Covid-19 more than once (e.g. due to a variation).