Delta variant

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.

India Confounds the Modellers

What happened to India’s summer and autumn waves? After suffering a large surge with the emergent Indian variant (i.e., Delta) in the spring, India has defied modellers’ predictions by remaining very quiet since.

In August, Rajib Dasgupta, Chair of the Centre of Social Medicine and Community Health at Jawaharlal Nehru University, wrote for the Conversation about the “likely” imminent new autumn surge.

With about 40,000 cases and 400 deaths each day as of mid August, a new uptick is likely in the cards. The Indian states experiencing most of these new cases are those with relatively lower sero-prevalence, ranging between 50% and 70%. The 400 million sero-negative pool – that is people who have not been infected or had the vaccine – continues to be a large vulnerable group.

Forecasting by modellers indicates a third wave beginning in August and peaking at 100,000 to 150,000 infections a day by October. An alternative projection expects the peak in cases going until November.

It’s October now and the reality, of course, is a low level of infections since June and no new surge throughout summer and autumn so far. Below is the graph showing the predictions from the modelling of Mathukumalli Vidyasagar and Manindra Agrawal of the Indian Institute of Technology that Rajib Dasgupta cites above. I have added in the line of actual ‘cases’, which shows that they have trended well below the ‘optimistic’ scenario since the moment the prediction was made.

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 Sharp Decline in Infections in Florida and the Southern U.S. Shows Once More That Covid Surges Peak and Decline Naturally Without Interventions

The Delta surge in England has remained muted, even as restrictions have been lifted and schools have returned. In Florida and other Southern U.S. states it has been more severe, but it is now clear that it peaked in mid to late August and is now in many places in steep decline. Florida, Mississippi and Georgia are famous for having lifted restrictions either last autumn or in the spring and not imposing new ones in response to the arrival of Delta. In Florida the Governor actively opposed the imposition of mask mandates by school districts. Yet new daily reported infections in the Sunshine State have been in steep decline for weeks – see the positivity graph above. Declining daily reported infections for the three southern states are shown below.

These states show what an unmitigated surge of the Delta variant can look like. They demonstrate, once again, that the epidemic peaks and declines naturally with no need for interventions.

The big question now is, is Delta the last variant, does it represent a kind of evolutionary endpoint for SARS-CoV-2, or will another variant capable of partial immune evasion and thus causing a surge emerge in the coming months?

The worldwide graph of reported infections (below) clearly shows the three variant-based waves since autumn 2020 – B.1.177 (20A.EU1, the ‘Spanish’ variant) in autumn 2020, Alpha in spring 2021 and Delta in the summer.

The Fatal Flaw in PHE’s New Study Claiming Delta “Doubles Risk of Hospitalisation” Compared to Alpha

A new study from Public Health England (PHE) and Cambridge University was published in the Lancet last week, claiming to find that the Delta variant “doubles a patients’ risk of hospitalisation compared to the Alpha variant”, as the Telegraph reported (as did the BBC).

Reviewing over 40,000 sequenced positive PCR test results from England between March 29th and May 23rd, 2021, the researchers found that 2.2% of Alpha infections (764/34,656) and 2.3% of Delta infections (196/8,682) were hospitalised within 14 days of their first positive test. However, once they adjusted for factors such as age, ethnicity and vaccination status they found the risk of hospitalisation from Delta more than doubled compared with Alpha (a 2.26-fold increase).

The authors took the opportunity to use the results to stress the importance of being vaccinated, noting that only two per cent of those hospitalised were double vaccinated. However, this data is out of date, as more recent data from the main Delta surge suggests that vaccine efficacy against Delta infection may be as low as 15%.

The finding that Delta is more than twice as serious as Alpha is surprising as official data shows that hospitalisations have been much lower with Delta than Alpha. Data in the PHE technical briefings on the variants of concern shows that between February 1st and August 15th, 2.9% of sequenced Alpha infections resulted in an overnight hospital stay, compared with 1.9% of sequenced Delta infections. Technical Briefing 21 (the most recent) acknowledges this but adds that “a more detailed analysis indicates a significantly greater risk of hospitalisation among Delta cases compared to Alpha (see page 50 of Variant Technical Briefing 15)”.

Technical Briefing 15 quotes the findings, then in pre-print form, which are now published in the Lancet study (I criticised an earlier version of the claim here).

March 29th to May 23rd, the study period, is notable for being a period of low prevalence in England, when there were only around 2,000 reported infections a day (compared to a peak of around 50,000). In the over-60s in that period there were only 100-200 reported infections per day.

Delta Surge Peaks and Declines in U.S. States

Some of the U.S. states which have been experiencing a Delta surge appear to have peaked. The chart above shows that Missouri has not seen sustained growth in daily reported infections since August 4th, Arkansas since August 7th, and Louisiana and Florida since August 13th. Since none of these states imposed new restrictions to try to combat the Delta variant, this demonstrates that a surge driven by the Delta variant, like those of previous variants, is self-limiting and, contrary to the predictions of the models, does not continue growing exponentially and infecting everyone not previously infected. Not everyone is equally susceptible. Will the modellers now adjust their assumptions to the realities observed on the ground?

Can Australia Contain Delta?

Until quite recently, Australia was the poster child for lockdown (along with New Zealand). Capitalising on its favourable geography, the country used a combination of strict border controls and early lockdowns to prevent the virus getting a foothold.

As a result, Australia saw fewer than 30,200 total cases up to June of 2021, and enjoyed negative excess mortality last year. Of course, I doubt that most countries (including the U.K.) could have achieved the same outcomes as Australia, which is not only a sparse island with few points of entry, but also had a head start in responding to COVID-19.

Yet with the recent entry of Delta, Australia’s ability to contain the virus could be reaching its limits. Today, the country posted its largest daily total for the number of new infections since the pandemic began. And as the chart below indicates, the curve for daily infections is now pointing almost straight upward:

The recent outbreak is concentrated in New South Wales, which is home to the country’s largest city, Sydney. (Infections have also shot up in the Australian Capital Territory, an enclave within New South Wales; though absolute numbers there are still low.)

Sydney’s most recent lockdown began on June 25th, after two dozen cases of the Delta variant were unearthed. What initially covered just four local government areas has since been expanded to the entire city. And today authorities announced the lockdown would remain in place until the end of September, including a 9pm to 5am curfew in some districts.

It’s now August 20th, which means that parts of Sydney have been under lockdown for almost two full months. Yet the curve of daily infections shows no signs of slowing. Why this time does the virus seem to have broken through?

The obvious explanation is that the Delta variant is more transmissible. And in fact, the more transmissible a virus, the less effective any given lockdown measures tend to be. As noted in a 2019 report by the Johns Hopkins Center for Heath Security, “Quarantine measures will be least effective for pathogens that are highly transmissible.”

Apple Staff Told They Won’t Return to the Office Unil 2022

Apple has scrapped its plans for corporate staff around the world to return to the office later this year, having decided not to welcome them back until January 2022 – at the earliest – instead. As seems to be the case with most recent news stories, this change comes because of fears over the Delta variant. The Guardian has the story.

The iPhone maker, which will still keep its network of retail stores open, had previously told staff there would be a phased return to work from October. The delayed office return applies to its international workforce, including those based in the U.K.

The company told staff in a memo that it would confirm the reopening plans one month before employees were required to return to the office, according to Bloomberg News.

The memo, sent by the Human Resources and Retail Head, Deirdre O’Brien, added that the company did not currently expect to close its offices or retail stores, but she strongly encouraged staff to get vaccinated. …

Apple, which last month reinstated the mask-wearing policy for in-store staff that it had only decided to scrap in June, had previously planned to ask staff to return to its offices on Mondays, Tuesdays and Thursdays by early September, before delaying that to October. Employees would be able to work remotely on Wednesdays and Fridays.

In the U.K., the company employs 7,000 staff and operates 38 retail stores, the most in any country in Europe. …

Apple is the latest major corporation to decide conditions are not yet safe enough to expect staff to return to offices.

Earlier this month, Microsoft said it would push back the reopening of its corporate offices from September until at least October 4th.

Amazon staff will remain working remotely until at least January 3rd, while Google has extended its voluntary work from home period until October 18th, having previously outlined plans for a September return.

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.

Florida’s Delta Surge Slows Towards a Peak

Florida’s Delta surge appears to be peaking. The chart below (from this very useful site) shows that, as of the week ending August 12th, the weekly increase in the percentage of Covid tests coming back positive has slowed almost to zero, meaning it should begin to drop soon. Indeed, the positive rate and new reported cases have already begun to fall in the north east of the state.

Since Florida’s Governor Ron DeSantis has refused to impose any new restrictions at all during this surge, having allowed the state of emergency to end in June, the Sunshine State looks set to confirm once again that coronavirus surges are self-limiting and it is not necessary to impose draconian restrictions on the population to prevent hospitals being overwhelmed or ‘hundreds of thousands’ of deaths.

Having had a very low infection rate throughout the spring despite imposing no restrictions, Florida has seen a large surge in infections during the summer since the arrival of the Delta variant, adding to evidence that surges are primarily driven by new variants which disrupt the previously established herd immunity by partially evading the immune response. The end of the surge after a few weeks of renewed spread therefore corresponds to the restoration of herd immunity. If this is correct, we should see new infections drop quickly across the state in the coming weeks.