Thread by @kakape

Getting a bit annoyed at everyone using numbers from yesterday’s Oxford pre-print to compare how often CVST occurs after mRNA vaccines and AstraZeneca vaccine.
We cannot directly compare these numbers because they came about in completely different ways.

The authors say so themselves IN the preprint:
"we cannot directly compare the risks of CVT associated with ChAdOx1 nCoV-19 with any of the other vaccines, or with COVID-19, since we are using data collected by the EMA monitoring system, not from the electronic health records..."

And yes, @UniofOxford press release does exactly that anyway:
"Compared to the AZ-Oxford vaccine, the risk of a CVT from COVID-19 is about 8 times greater."

This is one reason (of many) why we need science journalists and not just press releases.

ox.ac.uk/news/2021-04-1…

@UniofOxford So do mRNA vaccines increase risk of CVST compared to the general population?
Let’s hear the authors:
"we cannot conclude that the mRNA vaccines studied here are associated with an increased ris kof CVT; far larger samples are needed to address this question."

@UniofOxford So basically what most people seem to be taking away from this paper (at least in my timeline) and what the press release suggests is directly opposed to what the authors say in the paper.
I do wonder why @SMC_London decided to highlight this particular preprint with a presser.