#17,662
After early concerns over the large evolutionary leap taken by COVID variant BA.2.86, last week we unexpectedly saw the UKHSA Move COVID/Flu Jabs Forward Due To Concerns Over BA.2.86, after reporting only a couple of UK cases.
Since then, we've seen a number of reports and risk assessments (see here, here, and here) which have tempered initial concerns somewhat, calling into question both BA.2.86' transmissibility, and its degree of immune evasion.
But the reality is that epidemiological data remains frustratingly scarce, and laboratory tests - while useful - don't always translate into real-world results. And of course, BA.2.86 (and its myriad of viral cronies) continue to evolve.
Today the UK has released a new technical briefing; one that provides details on a care home outbreak with at least 28 confirmed cases due to BA.2.86, which they began investigating in late August.
While citing limited data, they state that this `. . . is an early indicator that it (BA.2.86) may be sufficiently transmissible to have impact in close contact settings'.
This early signal was likely the impetus behind the UK's decision to move up COVID jabs by nearly a month. Care home residents were among the earliest, and hardest hit, populations when COVID emerged in 2020.
First stop, a brief summary/update from the UK HSA.
UKHSA publishes latest BA.2.86 analysis in new technical briefing
The UK Health Security Agency (UKHSA) has published SARS-CoV-2 variant surveillance and assessment technical briefing 53. It contains the latest epidemiological and genomic analysis of the emergent BA.2.86 variant.
As of 4 September 2023, 34 confirmed cases of BA.2.86 had been identified in England. Of these, 5 were hospitalised and no deaths due to COVID-19 have been reported amongst these cases.
Multiple unlinked cases in different regions without reported travel history suggests a degree of community transmission within the UK. However, there is currently not enough data to conclude what the extent of this transmission might be. It is also too early to draw conclusions on the impact the variant may have on the UK population due either to its clinical or immune escape properties.
Of the 34 cases in England, 28 cases were from a single outbreak at a care home in Norfolk. Specialists from UKHSA have been working with Norfolk County Council to offer infection control advice and support.
Staff and residents of the care home were asked to undergo polymerase chain reaction (PCR) testing by local health protection officials when an unusually high number of people became unwell. Positive samples were sent for whole genome sequencing at UKHSA laboratories, where BA.2.86 was confirmed in the majority of samples.
Based on the information from this incident, it is too early to draw any conclusions about how BA.2.86 will behave in the wider UK population, but it is an early indicator that it may be sufficiently transmissible to have impact in close contact settings. UKHSA scientists are investigating this and will publish further analysis in future technical briefings. This variant has been detected in a number of countries globally.
Dr Renu Bindra, Incident Director, UKHSA said:
While BA.2.86 has a significant number of mutations to the viral genome compared to other currently circulating COVID-19 variants, the data so far is too limited to draw firm conclusions about the impact this will have on the transmissibility, severity or immune escape properties of the virus.
UKHSA scientists are working with international partners to culture the samples and analyse the evidence as it becomes available. However, it is likely to be some time before we have enough data to make a confident assessment.
Specialists from UKHSA have been working with Norfolk County Council to offer infection control advice and support following a confirmed outbreak of BA.2.86 in a care home.
It is clear that there is some degree of widespread community transmission, both in the UK and globally, and we are working to ascertain the full extent of this. In the meantime, it remains vital that all those eligible come forward to receive their autumn vaccine as soon as it is offered to them.
The Department of Health and Social Care (DHSC) announced last week that the autumn vaccine programme will be brought forward to 11 September as a precautionary measure following the emergence of BA.2.86.
Next, some excerpts from a much longer technical briefing, but you'll want to follow the link to read it in its entirety. I'll have a bit more after the break.
SARS-CoV-2 variant surveillance and assessment: technical briefing 53
Updated 8 September 2023
Applies to England
This report has been published to share the detailed variant surveillance analyses which contribute to the variant risk assessments and designation of new SARS-CoV-2 variants. This specialist technical briefing contains early data and analysis on emerging variants and findings have a high level of uncertainty.
Unless stated otherwise, this technical briefing uses a data cut-off of 4 September 2023 to allow time for analyses.
During periods when technical briefings are being published by the UK Health Security Agency (UKHSA), the routine variant prevalence and growth rate reports will be included in the technical briefing.
Situational assessment BA.2.86 (Variant Technical Group of 5 September 2023)
- There is a continued slow accumulation of cases globally including cases reported from new countries. The rate of detection of new sequenced cases cannot be used as an indicator of growth due to limited and lagging genomic surveillance globally.
- BA.2.86 is now more globally dispersed than other lineages of similar age in 2023. This may have been the result of international seeding from one or more unknown sources through mass travel. However, with apparent established transmission chains now in many countries, these seeding events are now unlikely to be the key driver of spread.
- The data suggest established community transmission of BA.2.86 within the UK. This is based on the detection of multiple unlinked cases in different regions of the UK, without identified travel links, and phylogeny (the relationship between cases as determined by viral genomic data). This finding does not confirm that BA.2.86 has a growth advantage within the UK compared to other circulating variants.
- A single care home outbreak was investigated due to a high attack rate and found to be BA.2.86. This cannot be used to make an assessment of the variant’s fitness but in contrast to recent laboratory data suggesting lower infectivity in vitro, this is an early indicator that the variant may be sufficiently transmissible to have impact in close contact settings.
- Pseudovirus neutralisation data is available from several laboratories. Whilst this data has limitations, antigenic cartography based on mouse sera is mostly consistent with the antigenic distances estimated from the mutational profile. The potential UK population impact after several vaccines and waves cannot be extrapolated from the available data.
- Some early indicators of increasing COVID-19 transthis is mission in the UK were noted and behavioural, immunological and virological factors may all be contributing. We cannot confirm that BA.2.86 is contributing to any increase given available data.
- There is an insufficient number of cases to make an assessment of outcome or severity. In the UK, the current surveillance systems do not support an assessment of comparative severity between variants but trends in severity and outcomes can be monitored over time through hospital data. It is likely that any such signal will take weeks to be visible and confirmed through sequencing.
Data summary
BA.2.86
As of 4 September 2023, there are 34 BA.2.86 sequenced cases in England, with cases located in East of England, London, and North West England. Of 34 total cases in England, 5 were hospitalised (2 have unknown hospitalisation status), and no deaths due to COVID-19 have been reported. These cases include 28 sequenced as part of an investigation of an outbreak in a care home which reported a high attack rate.
Cases in Scotland are reported by Public Health Scotland. There are no cases reported by Wales or Northern Ireland.
The global situation is dynamic with new cases identified daily. As of 5 September 2023, there are 33 sequences from human cases identified as BA.2.86 available in GISAID from 9 countries. The earliest collection date is 24 July 2023, and the most recent collection date is 26 August 2023. Of the 33 sequences, 2 are from the UK. The remaining UK sequence data will be uploaded to GISAID shortly, including those from the outbreak cluster described in this briefing. There are also multiple reports of BA.2.86 detected in wastewater in other countries though limited sequence data is available.
Virus was successfully isolated from the first UK case and passage 1 isolate has been shared with UKHSA; UKHSA and academic partners will undertake assessment using sera from UK studies.
(Continue . . . )
Quite obviously, despite recent reassuring reports, there is still a lot we don't know about the threat from BA.2.86. Its impressive attack rate in a highly vaccinated care home population is of obvious concern, but the lack of deaths is encouraging.
Because surveillance and reporting of COVID cases, hospitalizations, and deaths has become so unreliable, it may be some time before we get a good handle on what we may be facing this fall.
In the meantime we are likely to be subjected to a roller coaster ride of conflicting information. Opinions and assessments may help guide us, but it will be the virus that has the final say.
