Variants

Nailed It! Daily Sceptic Accurately Predicts the Delta Surge in Seven Countries

Two months ago Anthony Brookes, Professor of Genomics and Health Data Science at the University of Leicester, wrote an important piece for the Daily Sceptic in which he assembled the “Covid jigsaw pieces into a complete pandemic picture”.

To recap, this was his summary of his argument:

  • A series of SARS-CoV-2 variants have arisen, many of which possessed a transient selective advantage that led to a wave of infection that peaked some three-to-four months later. Several such variants have spread globally, though different successful variants have arisen simultaneously in a number of countries. The result is a three-to-four month wave pattern per country, which is also apparent globally.
  • Seasonality affects variant transmissibility. Colder seasons accelerate the growth and increase the size of waves, but the continually changing environment may also differentially affect the relative transmissibility of competing variants (i.e., negatively as well as positively), thereby helping to terminate previously dominant variants and promote the growth of new ones. 
  • Overall there is a minimal positive impact from quarantine policy, isolation requirements, Test and Trace regimes, social distancing, masking or other non-pharmaceutical interventions. Initially, these were the only tools in the tool-box of interventionist politicians and scientists. At best they slightly delayed the inevitable, but they also caused considerable collateral harms.  
  • Immunity created by SARS-CoV-2 infection, layered on top of pre-existing immunity due to cross-immunity to other coronaviruses, provides good protection against infection, severe disease/death, and being infectious. Immunity created by vaccination also helps protect against serious disease and death, but does little or nothing to provide protection against infection or being infectious (which completely negates the case for vaccine ID cards). 
  • Population immunity stems mainly from natural infections, with vaccines adding only slightly to this (and only in recent months). Population immunity is created by societal waves of infection and is somewhat variant-specific. An emerging new variant is able to infect (or re-infect) some fraction of individuals and this serves to top up and broaden the scope of our population immunity to also protect against the new variant. 
  • This empirical and data-driven understanding of the pandemic allows us to make predictions. Such predictions don’t look good for some of the U.K.’s new Green List countries. But in these and all other places the ongoing arms-race between viral mutations and growing human immunity will always eventually be won by the human immune system. The virus then becomes a low-level endemic pathogen in equilibrium with its human host species. If this were not the case all humans would have been wiped out by viruses eons ago!

In the piece he made some very specific predictions about what would happen over the following months, and we’re now in a position to see how close he got to the target. He wrote:

With an essentially complete Covid jigsaw picture now assembled using an empirical data-driven approach, we can offer up some testable predictions. The first is that current Delta waves unfolding in different countries will reach natural peaks around three-to-four months after this variant arrived in each location. For example, considering countries recently added to the U.K.’s Green List, we would expect: Slovenia, Slovakia and Romania (where Delta arrived little more than one month ago) will see their nascent summer waves grow further and peak in about two months’ time; Latvia (where Delta has only just arrived) will face a multi-month wave starting very soon; and Austria, Germany and Norway (where Delta has already been present for several months) will likely see their summer waves peak around the end of August. NPIs will do little to change this, and neither will vaccines (see Israel for evidence of this).

So the specific predictions were:

  • Reported cases in Slovenia, Slovakia and Romania peaking around about now.
  • Latvia to currently be on the up-slope.
  • Germany, Austria and Norway to peak around the end of August.

Let’s have a look.

Covid Unlikely to Mutate into a Deadly Variant, Says Lead Scientist Behind AstraZeneca Vaccine

There “aren’t many places for the virus to go”, according to the lead scientist behind the AstraZeneca Covid vaccine who says Covid is unlikely to mutate into a much deadlier variant. The Telegraph has the story.

Dame Sarah Gilbert said that viruses tended to become less virulent over time as they spread through a population which was becoming more immune.

Although Dame Sarah said some genetic drift was to be expected, she said Covid would eventually become like other seasonal coronaviruses which cause the common cold and respiratory infections.

Speaking on a Royal Society of Medicine webinar about variants on Wednesday, Dame Sarah said: “The virus can’t completely mutate because its spike protein has to interact with the ACE2 receptor on the surface of the human cell, in order to get inside that cell.

“If it changes its spike protein so much that it can’t interact with that receptor, then it’s not going to be able to get inside the cell. So there aren’t very many places for the virus to go to have something that will evade immunity but still be a really infectious virus.”

She added: “We normally see that viruses become less virulent as they circulate more easily and there is no reason to think we will have a more virulent version of SARS-CoV-2.

“We tend to see slow genetic drift of the virus and there will be gradual immunity developing in the population as there is to all the other seasonal coronaviruses. There are four of them and they’ve been circulating for decades and we’re not even aware of them.

“So we already live with four different human coronaviruses that we don’t really ever think about very much and eventually SARS-CoV-2 will become one of those. The question of how long it’s going to take to get there and what measures we’re going to have to take to manage it in the meantime.” …

Professor Sharon Peacock, the Executive Director of the Covid U.K. Genomics Consortium, which monitors variants for the Government, also told the webinar: “It’s watch and wait, but delta is top of the list and other variants are not particularly concerning at the moment.

“It has been pretty quiet since delta emerged and it would be nice to think there won’t be any new variants of concern. If I was pushed to predict, I think there will be new variants emerging over time and I think there is still quite a lot of road to travel down with this virus.”

Worth reading in full.

The Role of Variants in Driving Surges is Good News for Sceptics

As an addendum to my piece yesterday on the evidence for variants driving Covid surges, a comparison between India and neighbouring Bangladesh is illuminating. Once again, the curves below are the positive test rate and they are superimposed on the graphs of variant proportions over time from the CoVariants website.

India

India has had one large surge in 2021 so far, occurring in spring and associated with the Delta variant (which was first identified there; in dark green). It has had no summer surge, and no new variant since.

Bangladesh

Bangladesh, on the other hand, has had two peaks in 2021, a spring peak associated with the Beta variant (light red) and a summer one associated with the Delta variant.

The Compelling Evidence that Variants Drive Covid Surges

Recently, Anthony Brookes, a Professor of Genomics and Health Data Science at the University of Leicester, wrote a piece for the Daily Sceptic arguing that central to the virus’s surge-and-decline behaviour is the emergence of new variants, which are “able to infect (or re-infect) some fraction of individuals”.

He writes:

A series of SARS-CoV-2 variants have arisen, many of which possessed a transient selective advantage that led to a wave of infection that peaked some three-to-four months later. Several such variants have spread globally, though different successful variants have arisen simultaneously in a number of countries. The result is a three-to-four month wave pattern per country, which is also apparent globally.

The global wave pattern is shown below. It features an extended autumn and winter wave, a spring wave and a summer wave (seasons here for the northern hemisphere, of course). Note that this graph is raw positive test numbers so does not allow for increased testing.

To illustrate how this global pattern is reflected in different countries and how it relates to the emergence of new variants, I have superimposed the graph of variant proportions over time from the CoVariants website onto the positivity rate curves (the proportion of tests that come back positive, which takes into account changes in the amount of testing) from Our World in Data. I’ve done this for the 12 countries which have done the most sequencing of virus samples (according to CoVariants), plus Israel and South Africa.

Government Launching Antibody Testing Programme for Those Who Test Covid Positive

8,000 Brits who test positive for Covid next week will be sent antibody testing kits as part of a new Government programme seeking to identify people’s levels of protection against different Covid variants. Sky News has the story.

From Tuesday, anyone aged 18 or over in England, Wales, Northern Ireland and Scotland, will be able to opt in to the programme when receiving a PCR test.

If a participant tests positive for Covid then they will be sent two finger prick antibody tests to complete at home and send back for analysis. …

Up to 8,000 people will be rolled [sic] in the programme, according [to] the U.K. Health Security Agency (UKHSA), which is running it.

UKHSA, working alongside NHS Test and Trace, will use the results to monitor antibody levels in positive cases.

According to the Department of Health and Social Care, the programme will be the first time antibody tests have been made available to the general public.

The scheme could help DHSC build up information on groups of people who don’t develop an immune response after vaccination or infection.

The data could be used to “inform the ongoing approach to the pandemic and give further insight into the effectiveness of vaccines on new variants,” DHSC said.

Worth reading in full.

Double Jabbed Just as Likely to Spread Delta Variant as the Unvaccinated, According to New Study

A new study by researchers at Oxford University rubbishes plans to introduce vaccine passports as it shows that Covid vaccines do not significantly reduce transmission of the Delta variant. For the same reason, the researchers suggest that herd immunity is “unachievable”. MailOnline has the story.

Although fully vaccinated people are significantly less likely to be infected, those who do get Covid have a similar peak viral load as the unvaccinated.

This means infected people ‘shed’ the same amount of virus when they cough or sneeze, regardless of whether or not they have been jabbed.

Experts said the findings strengthened the argument for a ‘booster’ Covid jab programme this autumn.

However, the study stressed that two doses remain remarkably effective at preventing death and hospitalisation.  

And even though the viral load may peak at similar levels in the vaccinated and unvaccinated, scientists say it’s possible jabbed people clear the infection quicker.

The study, based on data from 700,000 Britons, is the largest yet to evaluate vaccine effectiveness against the Delta variant, which has been dominant in the U.K. since May. 

Researchers concluded two doses reduce the chance of getting the Covid by about 82% for Pfizer and 67% for AstraZeneca.

It follows similar findings by Public Health England and the U.S. Center for Disease Control and Prevention (CDC), which earlier this month released figures showing unvaccinated and double-jabbed have very similar viral loads. …

The researchers compared results from December 2020 to May 2021, when the Alpha variant was dominant, with those from May to August 2021, after the Indian [Delta] variant drove a summer wave.

The Delta variant has blunted the efficacy of vaccines as fully vaccinated people who do get Covid now have a similar peak ‘viral load’ as the unvaccinated.

This means they are just as likely to spread the virus onwards, and to develop mild symptoms such as a cough or temperature.

In contrast, vaccinated people who were infected with the Alpha variant had a much lower viral load and rarely got symptoms.

Worth reading in full.

Vaccines Don’t Stop Transmission and Won’t Give Us Herd Immunity, So Let’s Stop Mass Testing, Experts Tell MPs

A panel of experts has told MPs that there is no way of stopping Covid from spreading through the entire population because the vaccines don’t prevent infection and transmission, especially given the Delta variant, adding that we should stop worrying about community testing. “What matters is the burden of patient hospitalisation and critical care,” says a Consultant Paediatrician at Imperial College Healthcare NHS Trust. “And actually there hasn’t been as much with this Delta variant.” The Telegraph has more.

Scientists said it was time to accept that there was no way of stopping the virus spreading through the entire population, and monitoring people with mild symptoms was no longer helpful.

Professor Andrew Pollard, who led the Oxford vaccine team, said it was clear that the Delta variant could infect people who had been vaccinated, which made herd immunity impossible to reach even with high vaccine uptake. …

Speaking to the All-Party Parliamentary Group on Covid, Sir Andrew said: “Anyone who is still unvaccinated will, at some point, meet the virus. 

“We don’t have anything that will stop transmission, so I think we are in a situation where herd immunity is not a possibility and I suspect the virus will throw up a new variant that is even better at infecting vaccinated individuals.”

Until recently, it was hoped that increasing the number of Britons jabbed would create a ring of protection around the population. As late as last week, the Joint Committee on Vaccination and Immunisation said one of the reasons it had advised that 16 and 17 year-olds should be vaccinated was because it may help prevent a winter Covid wave.

However, analysis by Public Health England has shown that when vaccinated people catch the virus they have a similar viral load to unvaccinated individuals and may be as infectious.

Paul Hunter, Professor in Medicine at the University of East Anglia and an expert in infectious diseases, told the Committee: “The concept of herd immunity is unachievable because we know the infection will spread in unvaccinated populations and the latest data is suggesting that two doses is probably only 50% protective against infection.”

Professor Hunter, who advises the World Health Organisation on Covid, also said it was time to change the way the data was collected and recorded as the virus became endemic.

“We need to start moving away from just reporting infections, or just reporting positive cases admitted to hospital, to actually start reporting the number of people who are ill because of Covid,” he added. “Otherwise we are going to be frightening ourselves with very high numbers that actually don’t translate into disease burden.”

On Tuesday, Sajid Javid, the Health Secretary, confirmed that third dose booster shots would be given from next month. However, Sir Andrew argued that, if mass testing was not stopped, Britain could be in a situation of continually vaccinating the population.

“I think as we look at the adult population going forward, if we continue to chase community testing and are worried about those results, we’re going to end up in a situation where we’re constantly boosting to try and deal with something which is not manageable,” he said.

“It needs to be moving to clinically driven testing in which people are willing to get tested and treated and managed, rather than lots of community testing. If someone is unwell they should be tested, but for their contacts, if they’re not unwell then it makes sense for them to be in school and being educated.”

Worth reading in full.

Assembling Covid Jigsaw Pieces Into a Complete Pandemic Picture

We’re publishing an important piece today by Anthony Brookes, a Professor of Genomics and Health Data Science at the University of Leicester, in which he explains why the SARS-CoV-2 virus spreads across different populations in waves separated by three or four months. His theory is similar to that put forward by Dr Will Jones, namely, that the overall immunity levels in most populations are quite high, but need to be ‘topped up’ each time a new variant appears, causing infections to rise and then fall. Importantly, the decline in infections has little or nothing to do with non-pharmaceutical interventions – which is why daily cases started to decline before the second and third lockdowns were imposed in the U.K. and why the easing of restrictions on July 19th hasn’t caused an ‘exit wave’ – or the vaccine roll-out, since vaccines don’t appear to have much impact on infection or transmission.

Here is the abstract of Prof Brookes’s article:

  • A series of SARS-CoV-2 variants have arisen, many of which possessed a transient selective advantage that led to a wave of infection that peaked some three-to-four months later. Several such variants have spread globally, though different successful variants have arisen simultaneously in a number of countries. The result is a three-to-four month wave pattern per country, which is also apparent globally.
  • Seasonality affects variant transmissibility. Colder seasons accelerate the growth and increase the size of waves, but the continually changing environment may also differentially affect the relative transmissibility of competing variants (i.e., negatively as well as positively), thereby helping to terminate previously dominant variants and promote the growth of new ones.
  • Overall there is a minimal positive impact from quarantine policy, isolation requirements, Test and Trace regimes, social distancing, masking or other non-pharmaceutical interventions. Initially, these were the only tools in the tool-box of interventionist politicians and scientists. At best they slightly delayed the inevitable, but they also caused considerable collateral harms.
  • Immunity created by SARS-CoV-2 infection, layered on top of pre-existing immunity due to cross-immunity to other coronaviruses, provides good protection against infection, severe disease/death, and being infectious. Immunity created by vaccination also helps protect against serious disease and death, but does little or nothing to provide protection against infection or being infectious (which completely negates the case for vaccine ID cards).
  • Population immunity stems mainly from natural infections, with vaccines adding only slightly to this (and only in recent months). Population immunity is created by societal waves of infection and is somewhat variant-specific. An emerging new variant is able to infect (or re-infect) some fraction of individuals and this serves to top up and broaden the scope of our population immunity to also protect against the new variant.
  • This empirical and data-driven understanding of the pandemic allows us to make predictions. Such predictions don’t look good for some of the U.K.’s new Green List countries. But in these and all other places the ongoing arms-race between viral mutations and growing human immunity will always eventually be won by the human immune system. The virus then becomes a low-level endemic pathogen in equilibrium with its human host species. If this were not the case all humans would have been wiped out by viruses eons ago!

Worth reading in full.

Assembling Covid Jigsaw Pieces Into a Complete Pandemic Picture

by Anthony Brookes

Abstract

  • A series of SARS-CoV-2 variants have arisen, many of which possessed a transient selective advantage that led to a wave of infection that peaked some three-to-four months later. Several such variants have spread globally, though different successful variants have arisen simultaneously in a number of countries. The result is a three-to-four month wave pattern per country, which is also apparent globally.
  • Seasonality affects variant transmissibility. Colder seasons accelerate the growth and increase the size of waves, but the continually changing environment may also differentially affect the relative transmissibility of competing variants (i.e., negatively as well as positively), thereby helping to terminate previously dominant variants and promote the growth of new ones. 
  • Overall there is a minimal positive impact from quarantine policy, isolation requirements, Test and Trace regimes, social distancing, masking or other non-pharmaceutical interventions. Initially, these were the only tools in the tool-box of interventionist politicians and scientists. At best they slightly delayed the inevitable, but they also caused considerable collateral harms.  
  • Immunity created by SARS-CoV-2 infection, layered on top of pre-existing immunity due to cross-immunity to other coronaviruses, provides good protection against infection, severe disease/death, and being infectious. Immunity created by vaccination also helps protect against serious disease and death, but does little or nothing to provide protection against infection or being infectious (which completely negates the case for vaccine ID cards). 
  • Population immunity stems mainly from natural infections, with vaccines adding only slightly to this (and only in recent months). Population immunity is created by societal waves of infection and is somewhat variant-specific. An emerging new variant is able to infect (or re-infect) some fraction of individuals and this serves to top up and broaden the scope of our population immunity to also protect against the new variant. 
  • This empirical and data-driven understanding of the pandemic allows us to make predictions. Such predictions don’t look good for some of the U.K.’s new Green List countries. But in these and all other places the ongoing arms-race between viral mutations and growing human immunity will always eventually be won by the human immune system. The virus then becomes a low-level endemic pathogen in equilibrium with its human host species. If this were not the case all humans would have been wiped out by viruses eons ago!

For the past one and a half years, experts and amateurs alike have been trying to understand the Covid pandemic, hoping to be able to defend against it and predict how it will develop and end. A multitude of uncertainties has led to an environment of fear, and regrettably, that fear has been exaggerated and employed to justify policies that may or may not have been effective but were uncomfortably authoritarian. Perhaps it had to be this way, given that no one had a working crystal ball (not least the computer modellers) and yet people at all levels needed to feel they had some degree of control over the situation. The sad truth, however, is that our leaders, scientists and the public have basically been stumbling through the Covid quagmire, challenged by complexities of subjective data interpretation, imperfect modelling, political machinations, hidden agendas and unhelpful human egos.

Here, I attempt to pull together an empirical and rational summary of the underlying driving forces behind the whole pandemic. This is aided by the fact that modern genetic technologies have enabled extensive virus testing and variant detection, while vaccines and lockdowns have been applied to very different degrees in different countries thereby giving us many alternatives scenarios and empirical observations for direct comparison. From this, it becomes increasingly clear which factors did and did not truly drive the dynamics of the pandemic.

A central conclusion has to be that despite all our efforts, this SARS-Cov-2 virus has done what it was always determined to do. It spread across populations via waves of infection, and like ripples of water from a dropped stone these waves have been remarkably evenly spaced (by three-to-four months). This repeating pattern of rises and falls in virus prevalence has remained sufficiently synchronised across the planet to be apparent in the global death chart.

To make sense of this picture we need to consider the box of jigsaw pieces from which it can be constructed – that is, the range of factors that are driving (alone or in combination) the ability of the virus to spread well for a while before then losing that ability (operationally even if not innately), with uncanny regularity.

First up has to be the ‘virus variant’ piece of the puzzle. Time and time again we have seen new variants emerge which progressively displaced the previously dominant variant(s). As soon the ‘Wuhan’ variant began spreading around the globe, the forces of mutation and natural selection created an array of more transmissible strains that quickly supplanted the original strain. Many countries saw numerous variants competing with each other to achieve dominance, and several of these variants spread between countries. But within less than six months this initial ‘battle of the variants’ settled down to a far smaller number of the most transmissible variants which started to spread and dominate worldwide. Obvious examples include the Spanish variant (20A.EU1) of last summer/autumn, followed and displaced in many places by the U.K. variant (Alpha) just three-to-four months later over the autumn/winter/spring. And now three-to-four months after that, the Indian variant (Delta) has been establishing itself as the major variant almost everywhere. It is thus apparent that waves are being driven by variants that have some selective advantage(s), but critically we need to understand what the mechanism is that creates this advantage.

One big clue comes from the fact that each variant wave, regardless of location, continues to respect the noted three-to-four-month time period. Theoretically, replacement sweeps could entail variants that possess no or very little transmissibility advantage over other/previous variants. However, given the way some variants have been seen to spread between countries and then replace whatever previously dominant variant(s) existed in those other places, we can conclude that increased variant transmissibility is a large puzzle piece in the overall Covid picture. But saying that some variants have a significant transmission advantage at certain time periods and settings does not mean that this advantage is an inherent or a permanent property of that variant. This is because transmissibility depends on many other pieces of the puzzle.

One such additional puzzle piece is seasonality. Seasons change significantly over the timeframe of a few months, which is compatible with the rate of change for Covid waves. This makes seasonality a good candidate as a second large section of the Covid picture. Seasonality is widely accepted to have helped truncate the first U.K. wave in spring 2020, as the weather warmed up from mid-March. It is also notable that variants that arrive in a country during winter lead to new wave peaks in a far shorter time frame than they do in summer. But variant-driven waves occur in all the seasons, including in warmer periods (e.g. the Delta variant arose in India and spread to many other summer localities). So the seasonality puzzle piece might partly work by differentially changing the effective transmissibility of each variant. Specifically, as the seasons change, an initially dominant variant might find itself no longer especially compatible with the altered environmental conditions (and/or the associated changes in human behaviours). Conversely, one of the myriad background variants being repeatedly re-created by random mutation (or recently imported) might instead now be most suited to the new seasonal conditions. This new variant would then inevitably embark on a rapid replacement sweep. This rather obvious model of how evolutionary selection must work in a changing environment also fits perfectly with the observation that the secondary attack rate (SAR) of a new variant is initially higher (~15% according to PHE) but then reduces over a few months (<10%), even though the genome sequence of that variant is constant.

Several additional factors could contribute to making a dominant, highly transmissible variant less transmissible and less prevalent. Lockdown supporters would undoubtedly rummage through the box of Covid jigsaw pieces for anything having the appearance of a quarantine policy, an isolation requirement, a Test and Trace regime, a masked face, or some social distancing behaviour. Objective evidence indicates that such Non-Pharmaceutical Intervention (NPI) measures may together have had a marginal net effect on the rate of viral transmission, but overall they completely failed to halt the progress of the pandemic (see here, here and here). Instead, by slightly reducing the ease with which infections occur, they simply slowed the average rate at which people became infected (e.g. even a 50% reduced exposure would mean it simply takes four instead of two visits to a crowded environment to become infected). We know they did something because the incidence of all other respiratory viruses has reduced dramatically over the course of the pandemic wherever such measures were applied (even in Australia, where Covid is all but absent). Most respiratory viruses have Ro values of less than two, and so suppression measures need only be mildly potent to push these Rt values below one. In contrast, SARS-CoV-2 has a far greater Ro (typically estimated as three-to-four, or even more) and so those same suppression measures will not so easily push the covid virus Rt below one. Furthermore, people instinctively act more defensively when they know the virus is spreading rapidly, and so there may be very little added benefit of lockdown-related measures over just letting people respond naturally. This would then explain why there is no obvious impact of lockdowns in any curves of virus prevalence over time, why studies are yet to convincingly demonstrate any significant beneficial effect of lockdowns or masking, why virus prevalence began falling in the U.K. before the November 2020 and before the January 2021 lockdowns, and why we witnessed nothing whatsoever of the pessimistically-predicted massive ‘Exit Wave’ after the U.K.’s ‘Freedom Day’ on July 19th, 2021. So perhaps we allow NPI jigsaw pieces to have a token role as supporting edge pieces in the jigsaw, so long as we never overlook the enormous collateral damage they also impose (past, present and future).

That leaves just one final type of jigsaw piece – population immunity. Building on pre-existing cross-immunity to other coronaviruses, immunity due to SARS-CoV-2 infection is superior to immunity generated by vaccination in that it defends against a broader range of variants and engenders good protection against infection, illness and infectiousness. By contrast, vaccines do little to stop a vaccinated individual from becoming infected or being infectious (see here and here) and whatever small benefit they may provide in terms of reducing transmissibility will merely delay the occurrence of infections, as explained above for NPIs. Vaccines are, thankfully, very good at reducing serious illness, hospitalisation and death, and so on that basis they are only well merited for use in old and vulnerable individuals. It is critical that the very significant limitations of vaccines regarding infection and transmission control are now widely advertised and understood, as this makes the idea of vaccine ID cards completely nonsensical in scientific terms – as well as highly discriminatory and illiberal. Vaccine safety profiles are an additional consideration.

Nevertheless, to some degree, the combined effect of vaccines and natural infection generates our overall level of population immunity, and this must be playing some role in terminating each variant wave every three-to-four months. Substantial population immunity in the U.K. was achieved by the initial Covid waves of spring 2020, as evidenced by its impact on the development of second waves later that year. The peaking of each Covid wave in all places has little or nothing to do with lockdown measures (as explained above). It also cannot have much to do with immunity generated purely by vaccination, given that the vaccinated individuals still catch and pass on the virus, and that many waves ended in 2020 before vaccination campaigns got underway. This leaves only population immunity as an explanation, working in concert with the seasonality effects described above. 

To fully understand the role of herd immunity in wave termination, one must recognise that while the level of population immunity achieved at any stage may be sufficient to suppress the spread of a dominant variant (whose SAR may also be falling due to seasonality effects), it may not be sufficient to restrain the next emerging variant (whose SAR would be temporarily high owing to partial immune evasion or seasonal advantage). The new variant may also arise and spread in somewhat different sub-sections of society (age, ethnicity, geography, etc.) than did the previously dominant variant. Thus, herd immunity would be expected to have to be topped up and broadened by a wave of further infections and re-infections in society, in order to bring each subsequent wave to an end. This seems to be what is happening, with each sequential wave being generally smaller and ending naturally despite fewer suppression measures being enforced as populations tire of having their lives and freedoms excessively restricted. This also fits with the fact that over 95% of U.K. adults and 80% of 16-24 year-olds now have detectable Covid antibodies, much of which comes from natural infection. Others will be immune without detectable levels of antibodies, and from prior infections and cross-coronavirus immunity. 

So overall we can be pretty sure that population immunity is now contributing to (and possibly directly causing) the ending of each wave of Covid infections. It certainly has lowered the Infection Fatality Rate (IFR) down to or below that of influenza for society as a whole, meaning that the vaccination of the young cannot now be medically or ethically justified (especially given the substantial known and unknown risks imposed by these novel genetic technology vaccines). A scientific consensus on herd immunity will presumably begin to emerge, as the data and jigsaw pieces all continue to fall into place. Indeed, even lockdown champion Professor Neil Ferguson recently confirmed that because we have now released all lockdown measures in the U.K., this latest wave “will peak because herd immunity has been reached”. And it has indeed now peaked!

Finally, with an essentially complete Covid jigsaw picture now assembled using an empirical data-driven approach, we can offer up some testable predictions. The first is that current Delta waves unfolding in different countries will reach natural peaks around three-to-four months after this variant arrived in each location. For example, considering countries recently added to the U.K.’s Green List, we would expect: Slovenia, Slovakia and Romania (where Delta arrived little more than one month ago) will see their nascent summer waves grow further and peak in about two months’ time; Latvia (where Delta has only just arrived) will face a multi-month wave starting very soon; and Austria, Germany and Norway (where Delta has already been present for several months) will likely see their summer waves peak around the end of August. NPIs will do little to change this, and neither will vaccines (see Israel for evidence of this).

The really big question, however, is whether or not Delta is the last major variant we will all have to deal with. SARS-CoV-2 and the human immune system are basically in an arms race. Population immunity increases and targets the latest variant, causing new variants with different immunological profiles and transmission advantages to rise in abundance, which in turn further strengthens and broadens our population immunity. Vaccines merely help accelerate this arms race. But the end of the war is always the same – the virus runs out of strategies a long time before the highly adaptable immune system runs out of defences. The virus then gives up and resigns itself to becoming a low-level endemic pathogen in equilibrium with its human host species. If this were not the case all humans would have been wiped out by viruses eons ago! What we do not know is whether Delta is that last throw of the dice for Covid, or whether one or a few more guises of troublesome variants will yet come along. If they do, from what we now know we should probably place more trust in our immune system than we have in previous waves. And in either case, we can be very sure we are far closer to a permanent and natural end of this pandemic than we are to its beginning.

Anthony Brookes is a Professor of Genomics and Health Data Science at the University of Leicester.

The Figures Don’t Match Up To the Fear, a Doctor Writes

There follows a guest post from our in-house doctor, formerly a senior medic in the NHS, who says the widely trailed tsunami of hospitalisations has not only failed to arrive after ‘Freedom Day’, but we seem to be on the downslope of the ‘third wave’.

The philosopher Soren Kierkegaard once remarked: “Life can only be understood backwards, but must be lived forwards.” I have been reflecting on that comment, now we are three weeks since the inappropriately named July 19th ‘Freedom Day’. Readers will remember the cacophony of shrieking from assorted ‘health experts’ prophesying certain doom and a tidal wave of acute Covid admissions that would overwhelm our beleaguered NHS within a fortnight. Representatives from the World Health Organisation described the approach as “epidemiologically stupid”. A letter signed by 1,200 self-defined experts was published in the Lancet predicting imminent catastrophe.

Accordingly, this week I thought I should take a look at how the apocalypse is developing and then make some general observations on the centrality of trust and honesty in medical matters.

Let’s start with daily admissions to hospitals from the community in Graph One. Daily totals on the blue bars, seven-day rolling average on the orange line. Surprisingly the numbers are lower than on July 19th. How can that be?

Perhaps there are more patients stacking up in hospitals – sicker patients tend to stay longer and are hard to discharge, so the overall numbers can build up rather quickly. So, Graph Two shows Covid inpatients up to August 5th. Readers should note that Graph Two includes patients suffering from acute Covid (about 75% of the total) plus patients in hospital for non-Covid related illness, but testing positive for Covid (the remaining 25%). How strange – numbers seem to be falling, not rising. This does not fit with the hypothesis – what might explain this anomalous finding?

Maybe the numbers of patients in ICU might be on the increase – after all, both the Beta variant and the Delta variant were said to be both more transmissible and more deadly than the Alpha variant. Graph Three shows patients in ICU in English Hospitals up to August 5th. It shows a similar pattern to Graph Two – a small fall in overall patient numbers in the last two weeks. I looked into the Intensive Care National Audit and Research Centre ICU audit report up to July 30th. This confirms the overall impression from the top line figures. Older patients do not seem to be getting ill with Covid. Over half the admissions to ICU with Covid have body mass indices over 30. Severe illness is heavily skewed to patients with co-morbidities and the unvaccinated. Generally speaking, the patients have slightly less severe illness, shorter stays and lower mortality so far.

Finally, we look at Covid related deaths since January 1st, 2021, in Graph Four. A barely discernable increase since the beginning of April.

So, whatever is going on with respect to the progress of the pandemic, the widely trailed tsunami of hospitalisations has not arrived yet – in fact, we seem to be on the downslope of the ‘third wave’.