Title: Effectiveness of COVID-19 vaccines against the Omicron (B.1.1.529) variant of concern (2021-12-14)
BioNTech (Pfizer) vs Omicron:
BioNTech (Pfizer) vs Delta:
https://www.medrxiv.org/content/10.1101/2021.12.14.21267615v1
Title: Vaccine effectiveness and duration of protection of Comirnaty, Vaxzevria and Spikevax against mild and severe COVID-19 in the UK (2021-10-06)
BioNTech (Pfizer) vs Delta
https://www.medrxiv.org/content/10.1101/2021.09.15.21263583v2
Title: Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant (2021-08-12)
BioNTech/Pfizer/BNT162b2 after 2 doses:
Oxford/AstraZeneca/ChAdOx1 after 2 doses:
"Only modest differences in vaccine effectiveness were noted with the delta variant as compared with the alpha variant after the receipt of two vaccine doses."
https://www.nejm.org/doi/full/10.1056/NEJMoa2108891