This week, individuals who reported symptoms and tested in Pillar 2 (community testing) between 27 November 2021 and 6 January 2022 were included in the analysis. This corresponded to 236,023 Delta cases and 760,647 Omicron cases.
2/8
For Omicron, vaccine effectiveness against symptomatic disease for people who received two doses of AZ (ChAdOx1-2) following by either a Pfizer (BNT162b2) or Moderna (mRNA-1273) booster was ~45-50% and ~62%, respectively, after 10+ weeks.
3/8
Vaccine effectiveness against symptomatic disease for people who received two doses of Pfizer (BNT162b2) following by either a Pfizer (BNT162b2) or Moderna (mRNA-1273) booster was ~55% and ~65%, respectively, after 10+ weeks.
4/8
For people who received two doses of Moderna (mRNA-1273) followed by either a Pfizer (BNT162b2) or Moderna (mRNA-1273) booster, vaccine effectiveness against symptomatic disease with the Omicron variant was ~65% after 2-4 weeks.
5/8
This week, we had longer follow-up time to look at the effectiveness of the boosters against severe disease resulting in hospitalisation for the Omicron variant. VE against hospitalisation was 92% after 2-4 weeks, this waned slightly but remained high at 83% after 10+ weeks.
6/8
Together, these data continue to show that although vaccine effectiveness wanes faster for symptomatic disease caused by the Omicron variant than it does for the Delta variant, protection against severe disease appears well maintained.
7/8
Further data is needed to estimate the duration of protection against hospitalisation, and we will continue to investigate this as more data become available!
8/8
• • •
Missing some Tweet in this thread? You can try to
force a refresh
Today we publish our latest analysis where we stratify by age to investigate vaccine effectiveness (VE) against Omicron in adults aged 65 years and older in England.
This week's analysis is restricted to adults aged 65+ who reported symptoms and tested in Pillar 2 (community testing) between 27th November and 31st December 2021. Cases were defined as the Omicron or Delta variant based on whole genome sequencing, genotyping, or SGTF.
2/14
As before, a test negative case control design was used to estimate VE against symptomatic COVID-19 with the Omicron variant compared to the Delta variant.
This week, we were able to estimate vaccine effectiveness (VE) against hospitalisation for the first time. In short, good news. VE after a booster is close to 90%. The full update from our team is published in this week's technical briefing update:
As before, we first used a test-negative case control study design to estimate VE against symptomatic disease. This analysis included tests between 27th November and 24th December, and included 169,888 Delta cases and 204,036 Omicron cases.
2/10
Amongst those who received two doses of AZ (ChAdOx1-3), VE against symptomatic disease dropped to ~40% 10 weeks after a Pfizer (BNT162b2) booster and ~60% 5-9 weeks after a Moderna (mRNA-1273) booster.
An update from our team on the latest vaccine effectiveness (VE) estimates against symptomatic infection with the Omicron variant has now been published in the UKHSA Variant Technical Briefing 33 (page 24).
With more data available, we now have better estimates of VE following a booster (Pfizer or Moderna) after either an AZ or Pfizer primary course. We still did not have enough data to estimate VE against hospitalisation but we will be looking at this as as soon as possible.
2/9
As last time, we used a test-negative case control study design to estimate VE against symptomatic COVID-19 disease. This analysis included Pillar 2 testing data from 27th November to 17th December. Here, we had data from 68,489 Omicron cases and 147,597 Delta cases.
3/9
Our first initial estimates of vaccine effectiveness (VE) against symptomatic disease with the Omicron variant are now out. In short, VE remains high following a Pfizer booster after AZ or Pfizer, but is reduced after two doses.
More below 👇
1/11
We used a test negative case control design to estimate VE against symptomatic COVID-19 with the Omicron variant compared to Delta. The odds of vaccination in PCR positive cases was compared to the odds of vaccination in those who test negative.
2/11
Pillar 2 tests were classified as either Delta or Omicron from the period 27/11 – 6/12 based on sequencing and SGFT where sequencing wasn’t available. From 27/11, at least 80% of PCR tests which included the S-gene as a target and which had SGTF were the Omicron variant.