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Karlin Lillington: Why were groundless doubts on vaccine retweeted by believers in fact?

Confusion arose over claim in German media the AstraZeneca vaccine had very low efficacy in people over 65

Confusion this week over a claim in German media that the AstraZeneca vaccine had very low (8 per cent) efficacy in people over 65 – a claim quickly disputed by the company and various authorities – provides insights into how easily misinformation and disinformation spreads online.

I say this as someone who had a finger hovering over the “retweet”  button on this story.

But I paused. I went to look at the original stories, which I could not read myself as alas, my high school German has not held up through the decades. But I could verify that yes, the stories existed, one appearing on the website of the tabloid Bild and one on the broadsheet Handelsblatt.

Handelsblatt, as many were pointing out across social media, is a paper of some gravitas. I also found a thread from one of the Handelsblatt journalists explaining the background to the story and defending its publication.


So many elements in this story shouted for caution. The unnamed internal government sources. No confirmation from trusted medical sources

But still – the claim was unexpected and dramatic, with implications for hundreds of millions worldwide, and the consequences of spreading a story that might prove false, potentially devastating in the middle of a pandemic. I checked other international media sites to see if the story had been picked up. I couldn’t find anything. I searched through a Twitter list I follow that is focused on people with Covid expertise, full of researchers and medical experts. Mostly silence and a few circumspect discussions.

In the end, I didn’t retweet. But the claim was widely retweeted, generally with little additional context except some version of “wow”.

Twisting to deceive

It was retweeted by lots of people who are smart about the internet and care about information integrity. People who know a lot about the serious, daunting problems posed by internet disinformation campaigns.

That’s what brought me up short. So many of us who see ourselves as informed internet and social media users, as people ready to spot disinformation campaigns or the deliberate twisting of plausible misinformation to deceive, were very fast to tweet this story, or seriously consider doing so (me).

In doing so, we were participating in and nurturing a problem we generally prefer to think isn’t about Us, but about Them, those Others who deliberately disinform. But in a click, we chose to become part of a potential misinformation chain that’s always much harder to correct later, long after others have also glanced, clicked and shared.

So many elements in this story shouted for caution. The unnamed internal government sources. No confirmation from trusted medical sources. The statistical unlikelihood that a vaccine with 70-ish per cent efficacy overall, in peer-reviewed evidence, could plunge to just 8 per cent in over 65s. And, based on evidence, the vaccine had been approved by the UK regulator and was expected to be approved this week in the EU.

It seems the German stories were misinformation, based on a mangled understanding of trial figures

If the story was later shown to be wrong, then tweeting about it, especially without context, could bolster doubt about vaccines and provide fodder for vaccination deniers, at a moment when public health is precarious. The story would also worry people over 70 who have received this vaccine already in the UK. The fallout could dent confidence in national programmes, such as Ireland’s, which like many worldwide lean heavily on this vaccine.

Figures confused

In less than a day, the assertions about over-65s were rejected by the German health ministry, which suggested in a statement that the publications had confused figures: “Around 8 per cent of participants in the AstraZeneca efficacy trials were aged between 56 and 69 years old, only 3 to 4 per cent were over 70. This does not result in an efficacy of only 8 per cent among seniors.”

Researchers know that one reason effective disinformation spreads quickly is the inclusion of some plausible elements, enough to lend credence. The same for misinformation.

In this case, it seems the German stories were misinformation, based on a mangled understanding of trial figures.

But the concerns were now widely dispersed on social media. On Tuesday, they were being discussed on Irish news programmes.

A further development is likely to create even more confusion. On Tuesday, Emer Cooke, director of EU vaccine approval body the European Medicines Agency (EMA), indicated that some (unnamed) vaccines might not be approved for use in all age groups – which is nothing new and has long been seen as a possibility.

Her comments prompted speculation that the AstraZeneca vaccine might not be approved for older people. If that’s the case, the decision would indeed fit concerns some experts have over the limited data obtained so far for older age groups. But that is separate to the German claims, and not an indication that the vaccine does not work in the majority of older people.

Now though, any EMA decision along these lines is likely to be confused with the 8 per cent story, adding plausibility while feeding misinformation. It’s now a spreading, confusing mess.

With a click, every one of us can all too easily amplify misinformation or disinformation. It isn’t just Them. We need to pay more attention: sometimes, it’s Us.