Adam Clark Profile picture
Assistant Professor at Uni Graz. Used as a work account for discussing my research & related topics. For my personal views, see https://t.co/oEoHCvpASi….
7 Apr
I was disappointed by the news conference today from the EMA regarding #AstraZeneca. The upshot is that AZ has been tied to rare cerebral thrombosis, but EMA still believes that benefits outweigh the costs (on average). 1/n ema.europa.eu/en/news/astraz…
But, I am worried that we are going to have to eventually pay back the balance on three issues that have been largely pushed under the rug, but risk undermining public trust and slowing down vaccination campaigns in the the EU and worldwide: efficacy, risk, and side effects. 2/n
Regarding efficacy: among vaccines approved in the EU, AZ is the least effective at preventing mild to moderate COVID, especially with respect to variants (though there is reason to believe that efficacy against severe cases/death is still high). 3/n
Read 11 tweets
22 Feb
I don't was to get too far from my tree, but there's a growing issue at the stats/policy boundary regarding #AstraZeneka and #B1351 that I wish was getting more series coverage. The EU needs lots of people (20-30%?) to agree to be vaccinated with AZ, but many don't want to. 1/n
Reasons include lots of things that aren't well supported by data (e.g. "higher side-effects", "slower efficacy"), but also some that are, especially regarding very low efficacy against mild to moderate cases of the B.1.351 "South African" variant. 2/n
Nevertheless, people who know a lot more about immune responses than I do seem to be relatively sure that the AZ vaccine will protect against severe COVID cases, hospitalisation, and death, even for the B.1.351 variant. 3/n
Read 18 tweets
13 Feb
There's been a lot of media buzz around the efficacy of the AstraZeneca vaccine against the B.1.351 COVID-19 Variant first identified in South Africa. In particular, a recent study by @ShabirMadh et al. suggests it could be very low, at least for mild to moderate cases. 1/25
I've seen lots of people suggest that the sample sizes in the study are "too low" to say anything definitive - but, this is actually a pretty good opportunity for a power analysis. Since I haven't seen much discussion of the study's power, I thought I would post one here. 2/25
First, a few caveats. The study is available here: medrxiv.org/content/10.110…. This is a pre-print, and so results are not yet peer-reviewed, could potentially be subject to change. 3/25
Read 26 tweets