As the Delta variant continues to cause high case numbers of COVID-19 cases here in the UK concerns have been growing that the current vaccines are not protecting people from infection. With many cases and some deaths occurring in the double vaccinated, the media - both mainstream and social - has ample material for fear inducing headlines and blanket statements.
One day we are being told that there are more vaccinated people dying than non-vaccinated and therefore the vaccines are harming people; the next that the vaccines were working well and the problem is they now are waning. (1)
However, the vaccines still give good protection against severe illness and hospitalisations and the fact remains that the non-vaccinated are at far greater risk from COVID-19 than the vaccinated. (2)
It is true that the Delta variant is infecting fully vaccinated people and at a greater rate than any of the previous variants.
Israel, as discussed here in the blog last week, has seen its cases of COVID-19 surge from virtually zero to nearly 12,000 a day despite having rolled out an early vaccination programme.
The main problem with the Delta variant is that it is spreading more easily than previous variants and a higher number of infections will always result in a higher number of hospitalisations.
A study carried out in Scotland found that the risk of being hospitalised with COVID-19 caused by the Delta variant was double that of the Alpha variant (previously known as the UK variant.) There was however insufficient data to conclude if the Delta variant was more deadly. In other words, more people were being admitted to hospital with the Delta variant than with previous variants but there was no evidence that they were more likely to die. (3)
Vaccination continues to provide good protection against the Delta variant although one dose seems to offer less protection than it did against other variants, including the UK/Alpha variant. Both the Pfizer and AstraZeneca vaccines were only 33% effective against symptomatic disease from the Delta variant after the first dose compared to 50% effective against the Alpha variant after one dose. (4)
However, it is important to note that these figures are for the vaccines' effectiveness against symptomatic disease, not hospitalisation or death. If a COVID-19 vaccine is 60% effective against symptomatic disease that means the risk of becoming ill is 60% lower among vaccinated people than among those who have not been vaccinated. A 60% effectiveness against symptomatic disease does not mean the vaccine had a 40% failure rate. If nobody in the 40% group (who have received the vaccine but still got symptomatic COVID-19) ended up in hospital or died from COVID-19 that is not a failure. The 40% are still being protected from serious illness.
If we look instead at the vaccines’ success in preventing hospital admission from COVID-19 the figures are very encouraging. A preprint study by Public Health England has found that two doses of the Pfizer vaccine are 96% effective at preventing hospitalisation from the Delta variant. Two doses of the AstraZeneca vaccine are 92% effective at preventing hospitalisation from the Delta variant. This is comparable to the other variants. One dose of the Pfizer vaccine was 94% effective in preventing hospitalisation and one dose of the AstraZeneca vaccine was 71% effective. (5)
Whenever a percentage is given for a vaccine’s effectiveness it is crucial to know exactly what the endpoint is that is being measured.
How you can do anything with numbers....
So, if the vaccines are working, why are we seeing hospital admissions and deaths in people who have been double vaccinated? And what about the fact there are official reports showing there have been more deaths in vaccinated than non-vaccinated people?
When PHE (Public Health England) released its latest figures for COVID-19 deaths, those opposed to vaccination were quick to draw attention to the fact that there had been 3,546 cases of COVID-19 in the double vaccinated age 50 and over and only 976 cases in the non-vaccinated over 50s. (The vaccine sceptics were quick to gloss over the fact that in those aged under 50 there had been just 3,689 COVID-19 cases in the double vaccinated and a huge 52,846 cases in the non-vaccinated.)
They took the same approach with the death figures drawing attention to the fact that more double vaccinated people than non-vaccinated people had died in the 50 and over age bracket but again chose not to highlight the fact that all the deaths in the under 50s were in non-vaccinated people. (6)
Vaccine sceptics soon swamped social media with comments such as: “62% of England’s recent COVID-19 deaths are among vaccinated individuals.” (7)
However this took the PHE data completely out of context and this is why.
The risk of death from COVID-19 is much lower after vaccination, but it will never be zero. The take up rate of vaccine has been extremely high in those aged 50 and over and also in the clinically vulnerable, most high risk groups. This means that there are very few high-risk people who are still non-vaccinated. These same groups are the ones most likely to become seriously ill from COVID-19 and, knowing that no vaccine removes all risks, some deaths will still be expected in these groups sadly.
For every seven year increment in age, the risk of dying from COVID-19 doubles. In real terms this means that an non-vaccinated 70 year old is 32 times more likely to die from COVID-19 than an non-vaccinated 30 year old.
A double vaccinated 70 year old will still be at a higher risk of dying from COVID-19 than an non-vaccinated 30 year old BUT the 70 year old’s own, individual risk of dying from COVID-19 will have been substantially reduced from being vaccinated.
Correct analysis of the PHE shows that the vaccines reduce the risk of hospital admission and death by around 96% in the double vaccinated.
However, this huge decrease in the risk of death for our 70 year old double vaccinated person will still not take their risk below that of an non-vaccinated 30 year old.
To put this into real numbers, if 1000 double vaccinated people aged 70 are infected with COVID-19 we would expect four percent of them - 40 people - to still be hospitalised if the vaccines are 96% effective at preventing hospitalisation.
If 1000 non-vaccinated 30 year olds are infected with COVID-19 we would expect just one percent to need hospitalisation - that is 10 people.
Already we can see that just looking at crude figures they appear to say the double vaccinated are four times as likely to be hospitalised than the non-vaccinated, but this statement only applies if you skip over age boundaries and other factors such as underlying medical problems.
Instead, we should be looking at would what have happened to our 1000 70 year olds infected with COVID-19 if none of them were vaccinated. The data tells us that seventeen percent would have been hospitalised, which is 170 people - more than four times the number hospitalised than once they were double vaccinated. (8)
The real headline should be that without vaccines four times as many 70 year olds with COVID-19 would have been hospitalised than the current number.
The PHE figures do not show a positive correlation between being vaccinated and hospitalisation or dying from COVID-19. They show the opposite, that the vaccines are working. Although some vaccinated people will still become seriously ill or die it will be far, far fewer than if there were no vaccines available.
The very figures vaccine sceptics used to claim the vaccines don’t work prove the polar opposite –that they are working. (9)
If we reach a point where the entire population is vaccinated then every COVID-19 death will be in a vaccinated individual.
The media could then run headlines such as: “100% of deaths are in vaccinated people,” and conclude that we shouldn't be vaccinated. That is as meaningless as saying “All deaths occur in people who have been born,” and therefore concluding that in order to avoid death, one simply has to make sure one isn’t born in the first place.
But are the vaccines waning and becoming less effective?
Countries such as the UK and Israel were seeing their COVID-19 cases fall drastically when they first rolled put their vaccine campaigns. They are now seeing surges in case figures because of the Delta variant. Although the vaccines are very effective at keeping the risk of serious illness and death much lower than those seen in previous waves, it is now clear that they are not preventing milder cases of infection or transmission of the virus. In other words, vaccinated people can still become infected and pass the virus on.
Is this only because the Delta variant is much more infectious? Or are the vaccines not working as well? Or is immunity starting to fall away in those who were first vaccinated?
Laboratory studies in the UK, US and Israel all show that the vaccines, whilst not quite as effective against the Delta variant as they were against the Alpha variant, still work very well. The Delta variant still struggles to overcome the vaccines and is not in any way vaccine resistant. (9)
Researchers in the UK have also found that people infected with the Delta variant (as opposed to the Alpha variant) carry a greater viral load in their nose and throat and so are more likely to infect others. It is probable that the Delta variant is more infectious than the variants that went before it.
Real world (as opposed to laboratory) studies in the US found evidence of declining immunity against the Delta variant. However, these studies focused on the very elderly who were first vaccinated in December 2020 and before the Delta variant was dominant there. Immunity is expected to drop off more quickly in the elderly and frail after any vaccination, not just COVID-19, so findings in this age group cannot easily be extrapolated to firm conclusions.
In the UK researchers focused on the time period after the Delta variant became dominant here. They did find that the Delta variant was causing more infection breakthroughs in vaccinated people than previous variants had – but only slightly. (10)
This uptick in infections is being caused by factors other than a less effective vaccine. David Dowdy is an infectious disease epidemiologist at Johns Hopkins University and he noted that in a study in New York study the vaccines seemed to be less effective in younger people, the 18 to 49 year olds, not older people. Given what we know about how vaccines work less well with increasing age this was not expected. However, Dowdy has theorised that it is differences in behaviour between younger and older people that could be the underlying factor.
As lockdown restrictions were lifted younger people were more likely to be back in places such as clubs and restaurants and he made this observation: “People’s behaviour has changed substantially since the last wave with fewer masks and more large gatherings. The potential for more frequent—and more intense—exposure over time plays a role alongside Delta or possible waning vaccine immunity.” (11)
In other words, did the vaccines appear to work better against the Alpha variant simply because people were also still living under lockdown restrictions? In all three countries seeing a surge in the Delta variant - the UK, US and Israel - the surge also corresponded with a virtually complete lifting of restrictions. When we compare infections caused by the Delta variant with previous variants the problem is other variables have also changed, we are not comparing like with like in terms of our day to day living and interactions.
With hospitalisations and deaths remaining stable, despite a surge in Delta COVID-19 infections, the vaccines are still protecting us against severe disease. The uptick of infections in younger people represents three things: a more infectious variant - spreading round a partially vaccinated group - who are no longer living under lockdown restrictions.
In Conclusion
Despite claims to the contrary the vaccines continue to work well. No vaccine is 100% effective, be it for COVID-19 or any other infectious illness, but this does not mean they are failing.
A vaccine that is 96% protective against serious illness and death, despite the presence of a more infectious variant prevalent at the same time as the lifting of lockdowns, is not a failure.
(4) https://www.gov.uk/government/news/vaccines-highly-effective-against-b-1-617-2-variant-after-2-doses
(7) https://www.logically.ai/factchecks/library/57ec269b
