Thread by @ShamezLadhani

1/ Our team has just published the first #COVID19 vaccine effectiveness estimates against the Omicron vs Delta variant after 2 Pfizer or 2 AZ vaccine doses, and after a Pfizer booster 6 months later.

Here is a quick summary …🧵

More details here 👉 assets.publishing.service.gov.uk/government/upl…

2/ Effectiveness against #covid19 consistently lower for Omicron vs Delta at all timepoints. For Omicron: from 15 weeks after dose 2, little/no effect with AZ & <40% with Pfizer. A Pfizer booster 6 months after 2 AZ or 2 Pfizer doses significantly ⬆️ VE from 2 weeks post-booster

3/ The report also contains early household transmission risk assessment for Omicron vs Delta: 19% of Omicron index cases gave rise to a secondary household case vs 8.3% of Delta index cases 👉household transmission odds were 3.2-fold higher for Omicron than Delta @kallmemeg

4/ Important to note that these are very early analyses with very small numbers of Omicron cases in England. Better quality data with more robust estimates will emerge with time. But these early data are consistent with everything we know about the Omicron variant so far

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