Rachel Schraer

A viral tweet is claiming to give bombshell news (🚨) that Pfizer is "admitting" they never tested whether the vaccine prevented transmission and therefore the concept of "get vaccinated for others" was a lie - this is wrong on basically every count. So, some facts.

1. The vaccines were tested for whether they reduced people's chances of catching Covid - they seemed to, giving less chance of the virus being passed on. But they didn't look specifically at whether they stopped already infected people passing the virus on (transmission)

By the way, neither Pfizer nor health agencies claimed they had. This Nature article gives a good flavour of the discussions around the time https://www.nature.com/articles/d41586-021-00450-z So...

2. When the vaccines first became available, public health messaging was clear - we don't know whether they stop transmission, & people should continue keeping preventative measures. Here's the FDA - https://www.fda.gov/news-events/press-announcements/fda-takes-key-action-fight-against-covid-19-issuing-emergency-use-authorization-first-covid-19 here's the UK's DHSC - https://www.nhsbsa.nhs.uk/sites/default/files/2021-06/3%20CLINICAL%20SOP%20LFD%20PHARMACY%20COLLECT%20_%20Final%20%281%29.docx https://t.co/RwRpyTxLmE

3. Over time, stronger evidence *did* emerge they reduced transmission - of the variant at the time (this was before Delta). I wrote in March 2021 about how authorities were in fact being very cautious about confirming this https://www.bbc.co.uk/news/health-56514470

4. Then, new variants began to change the equation. The vaccines were less good at preventing transmission of Delta and even less good at preventing Omicron. This saw spikes in infections around the world

side-note: That *doesn't* mean they don't reduce transmission from Omicron at all - this is really tricky to disentangle from waning immunity and rising contacts. Some more info here https://ukhsa.blog.gov.uk/2022/02/10/how-well-do-vaccines-protect-against-omicron-what-the-data-shows/

5. In the UK at least, soon after it became clear vaccinated people could now pass on the virus at similar rates to unvaccinated people, vaccine passports were quickly all but dropped. That's not to say there aren't valid discussions about...

... whether they were the right policy in the first place (I wrote about some of the concerns here https://www.bbc.co.uk/news/health-56125142 ) - but let's get the basic facts straight. Was the idea your vaccine protects others based on a lie? No.

Wed Oct 12 15:58:17 +0000 2022