Some thoughts on the AstraZeneca vaccine, risk communication, and buyers remorse:

There are some threads on the go saying some pretty scary things about AZ. Credible people saying it shouldn’t be used. Many who got the shot based on “take the first you can get” feeling duped

This hit a fever pitch recently when Dr. Quiach from NACI made the statement that I still believe was not responsible sci comm. https://twitter.com/letsfishsmarter/status/1389337158264131585

Scientists have made all sorts of risk-reward tables to guess from a probability perspective whether it’s better to take AZ or not. To the million+ Canadians who have received this shot, it’s a moot point. This thing is in our bodies now.

People are scared and many feel duped. Many feel they can’t trust public health to be honest and open if adverse reactions are occurring. And to be frank, the behaviour of many top officials makes this understandable.

So what now? I’d suggest we re-think things a bit

The major problem with AZ is even if the rate of death or harm is very low, this is a vax that millions will receive. Low rate still translates into a lot of absolute harm.

But when we talk about collective harm, we also have to talk about collective benefit

Every single person who chose - at their own risk - to take an AZ shot has become one more point of friction in the transmission and growth of this pandemic.

Frontline workers have rolled the dice every day that they go to work without proper PPE, etc

For those of us who have been able to shelter ourselves during the storm, our relative safety has been made possible by people putting their bodies on the line every day.

The AZ shot shifts that risk from them, to us.

“But Pfizer is coming fast we could have just waited!” Right but part of the reason it IS going fast is because there are now a million+ people who are no longer in the Pfizer as first dose list. By taking AZ we have freed up those doses for others.

With your vax choice there is the axis of personal risk/reward, and collective risk/reward. If we emphasize only personal risk and collective risk, without also emphasizing collective benefit, THAT will exacerbate the feeling of being tricked.

If you got AZ:
- You are contributing to the collective project of all humans being protected from this virus
- You have chosen to protect others.
- Your absolute risk is still low, whether it’s 1/100000 or 1/25000
- you can mitigate that risk by acting fast if symptoms occur

And because everyone acted the risk calculus is shifting. As cases start to drop the collective risk will drop and then AZ will make less sense, particularly with abundant Pfizer.

But that doesn’t suggest that it was wrong for you to get that shot. Speed matters

And just as Dr Quiach reminded you of how bad you’d feel if your sister died from AZ, I’ll remind you how proud you should feel that your choice to get this vax may have saved someone’s sister. Maybe even your own.

To supplement my thread here’s one that explains the risk.

Again, if you have received AZ be vigilant but also remind yourself you contributed to an important community project of solidarity, and you made the best decision available to you given the info at the time. https://twitter.com/aspphysician/status/1391506010603462661