Saturday, September 23, 2023

UK HSA: COVID Technical Briefing & Updated Risk Assessment on BA.2.86


Despite an abundance of strong opinions on social media about what COVID variant BA.2.86 either will - or won't  do, thus far the number of confirmed cases around the world remains low, and reliable evidence remains limited. 

Much of this data `gap' can be attributed to the collective political decision to dismantle our COVID global surveillance and reporting system in order to `move on' from the pandemic.

It may have been good for the world's economies, and politically expedient, but it has left us at a distinct disadvantage when it comes to collecting and analyzing data on new and emerging COVID variants.   

Sadly, this `Don't test, don't tell' policy is also being used by many countries to obscure information on avian flu, MERS-CoV, and other emerging threats (see Flying Blind In The Viral Storm).

Which is at least one of the reasons why, more than a month after the UKHSA Initial Risk Assessment on BA.2.86 (Aug 18th), their newest assessment still uses terms like `likely' and `appears', and rates their findings as having either `low' or `moderate' confidence. 

All we can say with certainty is this new variant has a large number of mutations in its spike protein, representing the biggest antigenic change since Omicron burst onto the scene 2 years ago. 

First a link, and some brief excerpts from a much longer technical report, followed by some excerpts from a UKHSA press release. Follow the links to read both in their entirety.  I'll have a brief postscript  after the break. 

Research and analysis
SARS-CoV-2 variant surveillance and assessment: technical briefing 55
Updated 22 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 18 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.

Variant risk assessment BA.2.86 (Variant Technical Group of 19 September 2023)

  • Based on pseudovirus and live virus data from multiple UK and international centres, BA.2.86 is distant antigenically from previous Omicron viruses and is likely to have similar antibody escape to XBB.1.5 in the UK population context (moderate confidence)
  • Based on data from 2 laboratories, BA.2.86 appears to have slightly higher human ACE2 binding affinity than those XBB variants tested (low confidence). ACE2 binding affinity may be a factor in transmissibility.
  • Based on preliminary in vitro data and a small amount of animal data, there are no signals of concern regarding change in phenotype compared to other Omicron lineages (low confidence). However, no epidemiological assessment of clinical severity in patients is possible and the correlation between these laboratory studies and clinical severity is only partially understood.
  • BA.2.86 continues to transmit in the UK as evidenced by continued sporadic cases with no travel history in almost all regions (moderate confidence). It is circulating within a mix of variants which are antigenically distinct but which have similar or slightly greater level of escape from population immunity. Given this mixture and the characteristics of BA.2.86, it is plausible that the incidence of this variant may increase, but using the current low number of sequenced cases we cannot predict whether it will outcompete other circulating variants.
Real-world vaccine effectiveness studies on BA.2.86 and circulating variants will be published when sufficient data is available. Routine weekly updates on this emergent variant will now pause and reporting will return to standard variant prevalence updates.

        (Continue . . . .)

From: UK Health Security Agency Published September 2023  

UKHSA releases latest data on variant BA.2.86

The UK Health Security Agency (UKHSA) has published its latest variant technical briefing containing updated analysis of the emergent variant BA.2.86.

BA.2.86 continues to transmit within the UK, with sporadic cases identified in most regions.

The briefing contains early laboratory data from a number of scientific organisations around the UK, including UKHSA’s own Vaccine Development and Evaluation Centre (VDEC), the University of Oxford, the Glasgow Centre of Virus Research and the Pirbright Institute.

This early data indicates that BA.2.86 is no more likely to evade existing antibodies than XBB.1.5, another variant that has been circulating widely in the UK.

While the available data remains limited, there is currently no evidence to suggest that BA.2.86 infection is more likely to make people seriously ill than currently-circulating variants, while vaccination is likely to provide continued protection.

UKHSA will continue to monitor vaccine effectiveness in the population throughout the winter and will publish updated analysis in due course.

Professor Susan Hopkins, Chief Medical Advisor, UKHSA said:
While this is still very early data and more research is needed before we can be certain, it is encouraging to see an initial indication that BA.2.86 demonstrates similar levels of antibody escape compared to other variants circulating in the UK. The available data is too limited to draw conclusions about the severity of the illness it causes, but there is so far no evidence to suggest that it is more likely to make people seriously ill than other Omicron variants in circulation.

The autumn vaccination programme started this month, and this new data shows once again how important it is that the most vulnerable among us are fully vaccinated in order to receive the greatest possible protection. I urge everyone eligible to come forward for their next dose as soon as they are called.
The UKHSA technical briefing also includes initial findings of tests performed in the UKHSA laboratory at Porton Down to examine the effectiveness of lateral flow devices (LFDs) in detecting BA.2.86, which found no reduction in sensitivity compared to previous variants.

(Continue . . . )

It is still too early to know whether BA.2.86 is a flash in the pan, or the next `big thing'.  It has a lot of very `fit' competition (EG.5, XBB, etc.) to overcome, but it continues to evolve, and it (or one of its descendants) could gain momentum over time.

But most of all, it is a reminder that nearly 4 years after SARS-Cov-2 emerged on the global stage, it remains unpredictable, nimble, and capable of reinventing itself in a big way.

Traits and abilities you really don't want to underestimate in such a well-adapted, humanized, virus.