The UK vaccine advisory group, the JCVI, recommends that people aged 18 to 29 be offered an alternative vaccine where available. This graphic (UK risks) illustrates why. Note the importance of balancing harms.

What about if your exposure risk isn't low, but MEDIUM? Frontline workers, HCWs... The harms are static, but now COVID causes more harms. Vaccine benefit becomes more pronounced.

Now what if we're in a wave (which we are, in Canada). If all you have available is AZ vaccine, check out these risk/benefit numbers. (Also note that Canada has more than AZ available - our vaccine portfolio is impressive, when compared to other countries.)

Remember: I'm a thrombosis physician (and tweeter), not a public health expert, primary care physician, policy maker, epidemiologist. This isn't "flip flopping" or dithering by regulators: these are complex decisions being made in real time, based on evolving science.

It may feel scary, being caught in this swirl of info - but this means science, vaccine safety & surveillance, & regulation are all working. Let's watch how this info is put into the Canadian context. And remember: Canadian MDs know how to diagnose and treat these rare clots!

One last note before I go back to my real job: the slides above don't capture the risk to young people of getting long Covid after an infection, just ICU admission. And NB recent data: 1 in 3 Dx'd with neuropsych conditions post COVID.