Mary Wilson
Well-known member
Public Health England
9 July 2021
Technical briefing 18
This briefing provides an update on previous briefings up to 25 June 2021
Summary
There are 4 current variants of concern and 9 variants under investigation (Table 1).
This report has been published to continue sharing detailed surveillance of Delta (VOC- 21APR-02, B.1.617.2). A separate report is published covering our routine data on all other variants of concern and variants under investigation. The specialist technical briefings contain early data and analysis on emerging variants and findings have a high level of uncertainty.
Principal changes and findings this week are:
9 July 2021
Technical briefing 18
This briefing provides an update on previous briefings up to 25 June 2021
Summary
There are 4 current variants of concern and 9 variants under investigation (Table 1).
This report has been published to continue sharing detailed surveillance of Delta (VOC- 21APR-02, B.1.617.2). A separate report is published covering our routine data on all other variants of concern and variants under investigation. The specialist technical briefings contain early data and analysis on emerging variants and findings have a high level of uncertainty.
Principal changes and findings this week are:
- Delta variant accounted for approximately 99% of sequenced and 97% genotyped cases from 27 June to 3 July 2021
- the number of genome sequence results available is maintained but the coverage has fallen with the increasing case numbers
- secondary attack rates have fallen but remain higher for Delta than for Alpha. New data is included on the prevalence of mutations of predicted antigenic significance in the global dataset – there is an increase in mutations of predicted antigenic significance over time, even outside the designated variants of concern and variants under investigation
- additional spike mutations are occurring on Delta but are present at relatively low frequencies both in the UK and global datasets
- there is an increase in PCR positivity in the SIREN (national healthcare worker) cohort and a small but increasing number of possible reinfections
- two new variants in monitoring have been designated (B.1.619 and B.1.629, Table 1)