Early Warning Surveillance for SARS-CoV-2 Omicron Variants, United Kingdom, November 2021–September 2022

Abstract

the SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) Study has detected and investigated SARS-CoV-2 reinfections in the United Kingdom; after vaccine rollout, SIREN was adapted to monitor vaccine effectiveness (1-5). As the United Kingdom, like other countries, adapts to the postacute phase of the pandemic and reduced testing availability (6,7), SIREN has an ongoing function in national surveillance. SIREN informs the UK pandemic response by real-time monitoring of emerging variants and determining national rates of primary infection and reinfection. We describe SIREN's surveillance strategy and characterize emergence of Omicron subvariants during successive waves within the study.The Study SIREN is a large, multicenter, prospective cohort study of >44,000 UK healthcare workers from 135 secondary care health organizations. SIREN is led by the UK Health Security Agency in collaboration with Public Health Wales, Public Health Scotland, and the Public Health Agency Northern Ireland (1). Participants were initially followed for 12 months and had an option to extend to 24 months. Participants completed an initial enrollment survey regarding demographic and occupational data, then completed follow-up surveys every other week regarding symptoms, vaccination status, and occupational, household, and community SARS-CoV-2 exposures. Participants underwent PCR testing every 2 weeks and serologic testing monthly for the first

Effectiveness of BNT162b2 mRNA vaccine third doses and previous infection in protecting against SARS-CoV-2 infections during the Delta and Omicron variant waves; the UK SIREN cohort study September 2021 to February 2022

“…7 This continued in this current analysis, however the impact was markedly reduced in the Omicron period, and showed evidence of waning just nine months after infection. Given the distinct SARS-CoV-2 variant waves experienced by our cohort, 23 participants in the Omicron analysis who had been infected less than nine months previously were most likely infected by Delta-variant, those infected 9-12 months ago had Alpha-variant infections, and those infected over 15 months ago had Wild-type infections. Possible explanations for this lower protection afforded by a primary infection sustained over 9 months ago could be greater antigenic distance between successive variants, with a less effective neutralisation response to Omicron from a wildtype infection than a Delta infection, or antibody waning over time.…”

SARS-CoV-2 sequencing with cloud-based analysis illustrates expedient co-ordinated surveillance of viral genomic epidemiology across six continents

“…Better designed representative sampling would be immensely empowering and is likely possible through well-designed and suitably powered sampling frames. Ideally, this would be addressed through pandemic preparedness planning, enabling sequencing to be focussed at selected sentinel sites globally cognisant of national jurisdictions and the benefit of longitudinal data, as exemplified by a cohort design in the UK [25].…”

“…Ideally, this would be addressed through pandemic preparedness planning, enabling sequencing to be focussed at selected sentinel sites globally cognisant of national jurisdictions and the benefit of longitudinal data, as exemplified by a cohort design in the UK. [25]…”

“…Ideally, this would be addressed through pandemic preparedness planning, enabling sequencing to be focussed at selected sentinel sites globally cognisant of national jurisdictions and the benefit of longitudinal data, as exemplified by a cohort design in the UK. [25] Pathogen sequencing played a highly valuable role in the COVID-19 pandemic and remains a critical global and national capability. This is highlighted by studies of viral transmission that have yielded important insights into the modes of pathogen spread.…”

A weapon to fight against pervasive Omicron: systematic actions transiting to pre-COVID normal

“…The UK has also established an early warning tool, trying to extend the monitoring of medical staff to the society ( 43 ). In view of past successful experiences, some researchers suggested that hospitals formulate phased measures to ensure normal operation of public medical care ( 44 ). This type of alert system can provide dynamic practical guidance to respond to the evolving COVID-19 situation ( 45 ).…”