Let's fact check the latest nonsense being pushed by anti-vax Covid-deniers. Their crap gets more absurd all the time.
Anti-vaxxers say three doses of a COVID-19 vaccine results in higher infection rates. Here's why that's incorrect
https://www.abc.net.au/news/2022-03-25/coronacheck-ukhsa-report-negative-efficacy-false/100936440
CoronaCheck is a weekly newsletter from RMIT FactLab which recaps the latest in the world of fact checking and misinformation, drawing on the work of FactLab and its sister organisation, RMIT ABC Fact Check.
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CoronaCheck #105
This week, we explain how official UK data is being used to incorrectly suggest that being vaccinated against COVID-19 leads to a greater risk of catching the disease.
We also debunk a claim from a fringe Senate candidate who suggested that public health decisions in Australia were not being made locally, and detail how the Doherty Institute got dragged into a global biolab conspiracy theory.
No, the official UK data does not mean jabs put you at greater risk of COVID-19
Popular social media posts are pushing the argument that COVID-19 jabs have "negative efficacy", suggesting they increase — rather than decrease — the risks associated with the disease.
In one such video shared via Telegram, high-profile anti-vax campaigner Dr Ryan Cole tells the health committee of the general assembly of US state Tennessee:
"We've seen the data out of Denmark, out of Israel, out of the UK, where the shots actually turn into what we call negative efficacy, where your chances are higher from the shots of getting disease instead of being protective."
On March 13, a British journalist tweeted that the official data showed UK infection rates were "now higher in the triple vaccinated than the unvaccinated across all age groups … corresponding to negative vaccine effectiveness across the board".
But such claims are bogus, as fact checkers with FullFact and The Ferret have shown
time and again.
The UK data comes from weekly
surveillance reports published by England's UK Health and Security Agency (Table 13), which, on the face of it, appear to show that infection rates per 100,000 people really are higher among the vaccinated than the unvaccinated.
There are, however, well-documented problems with how infection rates are calculated for the unvaccinated group.
Put simply: no-one knows how many unvaccinated people there are.
To get around this, the health agency has relied on estimates drawn from a database called NIMS. And these estimates are very likely wrong.
Professor David Speigelhalter, a leading expert in risk communication with the University of Cambridge, told RMIT FactLab that the agency had used "inappropriate population estimates based on registrations with family doctors which are known to be overestimates due to multiple registrations and people leaving the country.
"This can make the unvaccinated group [the denominator] look too large, and hence the case rates misleadingly low."
FullFact has also
explained in detail the problems with using this denominator, and the UK national statistics regulator
has illustrated how using alternative population estimates would drastically affect the results.
Different population estimates can create different results.(UK OSR, via ONS, NIMS and UKHSA)
Those alternative estimates, produced by the Office for National Statistics, are much smaller so result in higher infection rates among the unvaccinated group.
Denominators aside, the health agency report
makes clear that infection rates should not be used to estimate vaccine effectiveness (which is calculated separately).
It explains in a
blog post: "This is because there are key differences in the characteristics and behaviour of individuals who are vaccinated compared to those who are unvaccinated", including their chances of taking a COVID-19 test.
"The rates therefore reflect this population's behaviour and exposure to COVID-19, not how well the vaccines work."
Notably, Public Health Scotland
stopped publishing infection rates by vaccination status after they were repeatedly misused, while the UK agency's reporting of them has been
publicly criticised by the national statistics regulator which, in November 2021, warned that the data potentially "misleads people into thinking it says something about vaccine effectiveness".
More recently, fact checkers with
Reuters and
Science Feedback have debunked claims that a Danish study found COVID-19 jabs to be negatively effective, explaining that comparisons were again likely biased due to different behaviours and exposure patterns in each group.
"Such biases are quite common in [vaccine effectiveness] estimation from observational studies based on population data (unlike a phase 3 randomised trial which is the gold standard)," one of the study's authors told Reuters.
In an email to FactLab, the Doherty Institute's Professor Terry Nolan said that, to his knowledge, there was "no evidence of negative efficacy for any COVID vaccine in either clinical trials or from post-marketing RWE [real world evidence]".
(More at above url)
