Vaccine efficacy

Alarming Data from PHE Shows the Fatality Rate in the Vaccinated Under-50s is 57% Greater Than in the Unvaccinated

Yesterday I wrote about the new data from Public Health England that allows us to make a (rough) calculation of vaccine efficacy during the Delta surge. Using data from technical briefings 17 and 20 I calculated that vaccine efficacy against infection with the Delta variant in the over-50s was a disappointing 17%. Vaccine efficacy against mortality was a better (if lower than expected) 77%.

The Daily Expose also published a piece looking at the new PHE data and argued that it showed vaccination was actually increasing the risk of hospitalisation and death. Their analysis did not break the results down by age, however, and so did not take into account that most of the infections are in the young, who are less vaccinated, and most of the deaths are in the old, who are much more vaccinated. That’s why my analysis focused on the over-50s, and when you do that you find the vaccines reduced mortality during the Delta surge in that age group by around 77%.

The Daily Expose article helpfully drew attention to the fact that in a recently published document, the Government advisers on SAGE themselves appear to admit that the vaccines do not prevent infection and transmission. In paragraph eight, they write:

While we feel that current vaccines are excellent for reducing the risk of hospital admission and disease, we propose that research be focused on vaccines that also induce high and durable levels of mucosal immunity in order to reduce infection of and transmission from vaccinated individuals. This could also reduce the possibility of variant selection in vaccinated individuals.

This being the case, why is SAGE not advising the Government to cease all aspects of the vaccination programme based on the idea of reducing transmission and protecting others (vaccine passports, the coercion of young people, vaccination of children and so on) as its members clearly don’t believe that these things are backed up by sound scientific evidence?

Alarming Data from PHE Shows the Fatality Rate in the Vaccinated Under-50s is 57% Greater Than in the UnvaccinatedRead More

By Will Jones  /  8 August 2021 • 02.00
     
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Devastating New Data From PHE Shows Vaccine Effectiveness Down to 17% and No Reduction in Infectiousness – But Mortality Cut by 77%

Public Health England yesterday released their latest technical briefing on the variants of concern, number 20, and it has some illuminating data.

It provides us with the infection, hospitalisation and death rates for the Delta variant, broken down by vaccination status and age. This allows us to do a calculation of the real-world vaccine effectiveness in the over-50s during the Delta surge, albeit a rough one without any adjustments.

The latest report has data up to August 2nd. If we substract from these values the data in Briefing 17 (up to June 21st) then we get the data covering the period June 22nd to August 2nd, which broadly corresponds to the bulk of the Delta surge in the U.K. The vaccine rollout to the over-50s was basically complete by this point, having stabilised according to PHE at around 88% double vaccinated and 10% unvaccinated (the other two per cent remaining single vaccinated, perhaps due to a bad reaction to the first dose).

In this period the PHE data tells us there were 2,464 Delta cases in the unvaccinated over-50s and 17,926 in the fully vaccinated over-50s. From this we can estimate the vaccine effectiveness against infection in the over-50s during the Delta surge as 17% (1-[(17,926/88%)/(2,464/10%)]). This confirms using additional data the estimate I made last week.

We can make a similarly rough calculation of the vaccine effectiveness against death. Between June 22nd and August 2nd, PHE reports that among the over-50s there were 339 deaths with the Delta variant in the double vaccinated and 167 in the unvaccinated. Using the same proportions vaccinated and unvaccinated as above, this gives a vaccine effectiveness against death in the over-50s during the Delta surge of 77% (1-[(339/88%)/(167/10%)]). Interestingly, this is very similar to the latest estimate of vaccine effectiveness against serious disease from Israel, which is around 80%. This is a decent level of protection and helps explain why the Delta surge had proportionally fewer hospitalisations and deaths, but it is well below the levels suggested by earlier studies and quoted by PHE, which are north of 95%.

Devastating New Data From PHE Shows Vaccine Effectiveness Down to 17% and No Reduction in Infectiousness – But Mortality Cut by 77%Read More

By Will Jones  /  6 August 2021 • 23.51
         
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Public Health Scotland Adds 85 Unvaccinated Deaths in a Week as it “Updates” its Reporting

Last week I reported on the latest data from Public Health Scotland (PHS), which showed that 87% of the deaths added in the most recent week (July 9th-15th) were in the vaccinated (one or two doses) and 74% were in the double vaccinated. I estimated from this that the vaccine effectiveness against death was a surprisingly low 46%, though acknowledged that this was a very crude estimate based only on one week’s data.

This week’s update is now out from PHS, and the data is surprising to say the least. Whereas in the week July 9th-15th, 38 deaths were added, only five of which were in the unvaccinated, just one of those aged over 70, in the week July 16th-22nd, 141 deaths were added, 85 of them in the unvaccinated, 78 of those aged over 70. This kind of change from one week to the next is obviously anomalous and presumably reflects some kind of reporting artefact.

Indeed, it turns out that PHS announced an update to their COVID-19 reporting on July 28th, which they said would be reflected in this week’s report and would include a “one off increase in reported deaths”.

This means we can discount the weekly change implied by this week’s report and resume our effort to deduce the vaccine effectiveness against death from next week.

By Will Jones  /  5 August 2021 • 22.46
       
19 comments

Latest Imperial REACT Report Finds Vaccine Effectiveness Could Be As Low as 22% – and Under-64s Are at Greater Risk of Hospitalisation Than Before the Vaccines

The report from round 13 of Imperial College’s REACT-1 Covid infection survey was published yesterday, covering the period from June 24th to July 12th, broadly corresponding to the Delta surge.

The press release led with the claim that “double vaccinated people were three times less likely than unvaccinated people to test positive for the coronavirus” (0.4% vs 1.2%). This is clearly misleading as an indication of vaccine effectiveness, however, as younger people were both less likely to be vaccinated and more likely to test positive. As the report itself admits: “These estimates conflate the effect of vaccination with other correlated variables such as age, which is strongly associated with the likelihood of having been vaccinated and also acts as a proxy for differences in behaviour across the age groups.”

Presumably, the headline was chosen by a politically savvy communications officer who did not want to draw attention to the fact that the study found a lower vaccine effectiveness than other studies such as those of Public Health England.

It found a vaccine effectiveness (vaccine type unspecified) among 18-64 year-olds of 49%. However, the 95% confidence interval ran from 22% to 67%, meaning the authors didn’t have enough positive test results to be very sure of their estimate (despite testing nearly 100,000 people, only 527 results or 0.54% came back positive). They couldn’t even be very confident it wasn’t as low as 22%.

Latest Imperial REACT Report Finds Vaccine Effectiveness Could Be As Low as 22% – and Under-64s Are at Greater Risk of Hospitalisation Than Before the VaccinesRead More

By Will Jones  /  5 August 2021 • 00.50
         
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Does This Data From Public Health Scotland Show that Vaccine Effectiveness Against Death is Just 46%?

How well do the vaccines protect from death? The two most recent weekly reports from Public Health Scotland give us death data by vaccination status, and by subtracting one from the other we can work out how many Covid patients died in the week July 9th-15th. The results are shown below.

We see that 38 people died with Covid that week, 37 of whom were over 50. Twenty-eight (74%) were fully vaccinated (18 of whom were over 80 and 24 were over 70). Thirty-three (87%) had had at least one dose. Just five (13%) were unvaccinated.

To fully interpret these we need to know how many people were vaccinated in each age group. The problem with obtaining this information is that the official Scottish statistics appear to use the same method as the NHS for estimating vaccine coverage, which gives figures which exceed the likely more accurate estimates of Public Health England by around 5%.

Does This Data From Public Health Scotland Show that Vaccine Effectiveness Against Death is Just 46%?Read More

By Will Jones  /  2 August 2021 • 00.55
       
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PHE Data Shows Vaccine Effectiveness Reduced to Just 17% In Over-50s

The data from the two most recent technical briefings (No. 18, published July 9th, and No. 19, published July 23rd) from Public Health England shows that vaccine effectiveness against infection in the over-50s has plummeted to just 17% in the month between June 21st and July 19th, which corresponds to the main Delta surge.

The data is derived by subtracting the figures in table 5 in briefing 18 (up to June 21st) from those in briefing 19 (up to July 19th) to give just the data for the intervening period.

Briefing 18 gives 9,885 ‘cases’ of the Delta variant in those over 50 who have received at least one vaccine dose and 1,267 ‘cases’ in the unvaccinated over 50 up to June 21st. Briefing 19 gives 18,873 ‘cases’ in the vaccinated and 2,337 in the unvaccinated for the period up to July 19th. Subtracting the earlier from the later gives 8,988 ‘cases’ in the vaccinated and 1,070 in the unvaccinated for the month from June 21st to July 19th.

To calculate the vaccine effectiveness we need to know the infection rate in the vaccinated and unvaccinated groups. According to the PHE week 29 surveillance report, as of July 18th, 20,331,977 people over 50 in England were vaccinated and 2,016,818 were unvaccinated. This gives an infection rate in the vaccinated of 0.044% and an infection rate in the unvaccinated of 0.053%.

Vaccine effectiveness can be calculated by dividing the infection rate in the vaccinated by the infection rate in the unvaccinated and taking away from 100%. Thus 0.044/0.053 gives a vaccine effectiveness of 16.7%, which rounds to 17%.

PHE has recently published a study in the NEJM claiming vaccine effectiveness against the Delta variant of 67% for AstraZeneca and 88% for Pfizer. However, that was using data from April and May when prevalence was very low. This data is from the recent surge in the Delta variant, which is when vaccine effectiveness is really tested. Like recent data from the surge in Israel, it shows that vaccine effectiveness against infection is not holding up.

As noted yesterday, vaccine effectiveness against serious disease and death appears to be holding up much better. This means that those who see vaccines as the necessary pre-condition to removing restrictions don’t need to change course. However, it does indicate that vaccines do little to prevent infection or transmission and so there is no justification for vaccinating young people and children to protect others, or for any coercive measures like vaccine passports. Each person can be free to weigh up the risks and benefits of being vaccinated for themselves.

This article has been updated.

By Will Jones  /  25 July 2021 • 15.51
       
65 comments

New Data Casts Doubt on the Effectiveness of Covid Vaccines Against Infection

A snapshot of data from the beginning of the month in Israel suggests that the Pfizer vaccine is not protecting against infection now the Delta variant is in town, with infections in the vaccinated across all age groups being no less than you’d expect if the vaccine did nothing.

Could there be another explanation here? Possibly. It’s only a snapshot. What if infections in the unvaccinated peaked earlier than in the vaccinated, as ZOE data at one point showed happening in the U.K.?

Talking of ZOE data, in the middle of last week the study updated its methods (described here) which had the result of completely removing the peak in the unvaccinated infections and replacing it with the opposite, a further climb (see below, the old method put the peak around July 1st).

New Data Casts Doubt on the Effectiveness of Covid Vaccines Against InfectionRead More

By Will Jones  /  24 July 2021 • 17.51
         
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Infections Surge Among the Vaccinated While Those in the Unvaccinated Plateau, Data Shows

One of the few places that publishes daily information on the infection rate in vaccinated and unvaccinated people is the ZOE Covid Symptom study. Above is today’s estimate for the U.K., based on the data submitted by users through the ZOE app, and it shows something very striking. While the infection rate in vaccinated people has been trending well below that in the unvaccinated for months, in the last two weeks the rate in the vaccinated has surged while that in the unvaccinated has plateaued.

We don’t know what is causing this. The vaccinated group is older than the unvaccinated group, which will skew its infection rate lower as older age groups have a lower infection rate anyway (see below). The currently slowing growth in the younger age groups and the increasing growth in the older, more vaccinated age groups is likely to be a reflection of the same underlying infection patterns as those in the vaccinated and unvaccinated groups.

Infections Surge Among the Vaccinated While Those in the Unvaccinated Plateau, Data ShowsRead More

By Will Jones  /  7 July 2021 • 18.45
     
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Pfizer Vaccine Effectiveness Drops to 64% in Israel

As infections have surged in Israel in the last few weeks, the Israeli Government reports that the effectiveness of the Pfizer vaccine against infection has dropped to 64% from 94% the previous month. However, its effectiveness against serious disease is holding up. The Telegraph has more.

The vaccine had a 64% efficacy rate from early June until early July, the latest figures show, down from 94% a month earlier. The decrease coincides with a period in which the government reversed coronavirus restrictions and the delta variant spread through the country.

But the vaccine is still conferring strong protection against severe symptoms of the virus, with hospitalisation rates remaining low. The ministry’s data shows the vaccine’s efficacy in preventing hospitalisation was 93% from June 6th to July 3rd, compared to a 98% rate in the previous period.

On Monday, Israel reported the highest rate of new infections since the start of its most recent outbreaks, with the ministry recording 343 new cases over the past 24 hours.

Over half (55%) of the new infections are in fully vaccinated people, according to recent data. Since the country has fully vaccinated about 60% of the population, this suggests the vaccine is not protecting from infection very much at all (less even than the new stated efficacy figure of 64%). This is particularly so given that most of the infections are likely to be in socially and economically active younger people (like they are in the U.K.) who have lower vaccination rates, so that the vaccinated may even be suffering disproportionately more infections than the unvaccinated (the data is currently unavailable to confirm this).

The pattern of outbreaks in highly vaccinated countries such as Bahrain, Seychelles, Maldives and Chile and the fact that the vaccines don’t produce mucosal IgA antibodies has suggested for a while that their effectiveness against infection may have been exaggerated in studies. The idea that the IgG antibodies they produce in the blood should protect against progression to serious illness makes more sense and it is reassuring to see this data holding up.

The Israeli Government is now discussing the need for a third booster shot, and Pfizer CEO Albert Bourla has said people will “likely” need a third dose within 12 months of getting “fully vaccinated”. The Government may also consider limiting gathering sizes and reintroducing the controversial “Green Pass” vaccine apartheid system.

However, if a highly vaccinated country like Israel cannot return to normal without constant threat of new restrictions you have to wonder if anyone can. At some point leaders will need to accept that they have done all they can to guard the vulnerable against serious illness and death and remember that there is more to life than avoiding COVID-19.

Stop Press: The Centers for Disease Control and Prevention (CDC) is now investigating the death of a 13 year-old American boy who died a few days after receiving his second dose of the Pfizer Covid vaccine.

By Will Jones  /  5 July 2021 • 13.34
     
110 comments

PHE’s Latest Vaccine Study Suggests Hospitalisation Risk INCREASES After the Second Dose

It’s not two weeks since Lockdown Sceptics was casting doubt on Public Health England’s alarming claim that the Delta (Indian) variant had more than double the risk of hospitalisation of the Alpha (British) variant. How long will they take to backtrack after the panic has done its damage, we asked?

Well, it turns out that even before Boris took to the podium on Monday PHE had already released a new study claiming that vaccines after all are more effective at preventing hospitalisation against the Delta variant than the Alpha variant. Here’s the story in the Telegraph:

Vaccines are more effective at preventing hospitalisation against the Indian/delta variant than they were against previous types, once people are double-jabbed, new data shows.

Real world data shows the Pfizer/BioNTech vaccine is 94% effective against hospital admission from the variant after one dose, rising to 96% after two jabs.

The Oxford/AstraZeneca vaccine was found to be 71% effective against hospital admission after one dose, rising to 92% after two jabs.

In both cases, two doses had a greater impact preventing hospitalisations than was the case with the Kent variant. 

The new study and the earlier study aren’t quite showing the same thing. The earlier study showed the risk of hospitalisation with the Delta versus Alpha variant for all those testing positive, not just the vaccinated, though subsequently adjusted the results for “vaccination status”. The new study specifically looks at the hospitalisation risk in those vaccinated with respect to the Alpha and Delta variants and compares them. However, the two studies should come to broadly the same conclusion, as they are both looking at how much more serious disease is with the Delta variant. At any rate, given that a large proportion of the vulnerable population is now fully vaccinated, we certainly shouldn’t see a doubling in the hospitalisation rate with the Delta variant if, as is claimed in the new study, the vaccines are better at preventing serious disease from that variant.

Ross Clark suggests the problem with the earlier data was that the sample size was small and biased. As he notes, PHE’s modelling misses the most obvious data point, that the rate of hospitalisations per case has not increased as the Indian variant has become dominant (see graph below). How then can the Indian variant have twice the risk of hospitalisation?

Spectator

Is the new study any more reliable than the earlier one? As usual with a PHE observational study, it’s hard to tell, as much of the method is hidden behind opaque statistical techniques with working that is not set out. All the reader knows is that raw data is taken and transformed by some statistical process into hazard ratios and vaccine effectiveness estimates that are all but impossibly to verify. What we can do, though, is look at the results of this largely concealed data-processing and see if it makes sense.

Below is the table from the study (there’s only one, it’s a very short paper), and it shows something very curious.

PHE’s Latest Vaccine Study Suggests Hospitalisation Risk INCREASES After the Second DoseRead More

By Will Jones  /  16 June 2021 • 01.41
       
43 comments