SAGE 88 minutes: Coronavirus (COVID-19) response, 5 May 2021

Eighty-eighth SAGE meeting on COVID-19, 05 May 2021
Held via Video Teleconference
Summary

  1. There has been a significant recent increase in prevalence of the B.1.617.2 variant,
    including some community transmission. PHE is currently prioritising case finding
    and containment for this variant. Early indications, including from international
    experience, are that this variant may be more transmissible than the B.1.1.7 variant
    (low confidence).
  2. SARS-CoV-2 is continuing to evolve antigenically (high confidence). There is a need
    for medium and long-term strategies for vaccination in response to this. Effective
    vaccine updates will require coordinated virus and immunity surveillance, linked to
    serology, immunology, structural biology, and viral phenotyping. The UK should build
    on what it has developed during the pandemic to create a sustainable hub for this.
  3. Modelling shows that taking step 3 of the roadmap is alone highly unlikely to put
    unsustainable pressure on the NHS. It is, however, likely to lead to R being greater
    than 1 in England, and therefore an increase in infections. The full impact of step 3
    on hospitalisations and deaths will not be seen until mid-June at the earliest.
  4. It remains highly likely that there will be a further resurgence in hospitalisations and
    deaths at some point, however, the scale, shape, and timing remain highly uncertain.
  5. The resurgence will be smaller if baseline measures and sustained changes in
    behaviour which reduce transmission are maintained beyond the end of the roadmap
    (high confidence). The speed of vaccine rollout is also a key factor in the size of the
    resurgence (high confidence). The two biggest risks (absent new variants) are that
    either high contact patterns emerge early, or there is low vaccine rollout amongst
    younger adults. The combination of these two would lead to a larger resurgence.
  6. A variant which either substantially escapes immunity or is highly transmissible (more
    so than B.1.1.7) could lead to a very significant wave of infections, potentially larger
    than that seen in January 2021 if there were no interventions. Given the uncertainty
    around the properties of any such variant the modelling is based on some illustrative
    scenarios only. Maintaining control of transmission of any such variants will be more
    difficult when there are fewer measures in place. Reducing the number of variant
    infections should be a priority for policy.
  7. There remain several sources of uncertainty in the modelling, including around
    behavioural responses to changes in policy (after both step 3 and step 4), the impact
    of any seasonal variation in transmission, the extent of waning immunity, vaccine
    rollout speed, and the impact of vaccination on transmission (including from
    asymptomatic infected people).
    Situation Update
  8. SPI-M estimates that there are between 1,000 and 5,000 new infections per day in
    England.
  9. R is estimated to be between 0.8 and 1.0 in England, between 0.7 and 1.0 for both
    Scotland and Wales, and between 0.8 and 1.1 for Northern Ireland. Current
    estimates do not yet fully reflect recent changes, such as the return of schools after
    Easter holidays, but will reflect behavioural changes since the easing of restrictions in
    England on 12th April.
  10. At a local level, estimates of R for most areas from one analysis have increased over
    the last fortnight, but in most cases remain below 1 (though there are local areas in
    all nations where the epidemic is increasing). If there is a small overall increase in
    transmission nationally (e.g., due to relaxation of restrictions), R would go above 1 in
    many more areas. In these cases, local outbreaks could coalesce and lead to
    regional transmission. As SAGE has advised previously, dealing with outbreaks
    quickly will be important.
  11. Comparing CoMix timeseries data with infections and hospitalisations shows that in
    the past increases in contacts have been followed by increases in R, infections, and
    hospitalisations. In 2020 the number of contacts remained low until the start of
    August, despite there being many policy changes over that period. There has been a
    recent increase in the number of adult contacts, but this remains lower than that seen
    last August and is increasing more slowly. Contact survey data and mobility data will
    continue to be useful lead indicators.
  12. There has been a significant recent increase in prevalence of the B.1.617.2 variant,
    including some community transmission. PHE is currently prioritising case finding
    and containment for this variant. Early indications, including from international
    experience, are that this variant may be more transmissible than the B.1.1.7 variant
    (low confidence). One hypothesis is that this is linked to the P681R mutation.
  13. Sequencing all cases from hospital patients remains important for surveillance and
    understanding of the impact of variants.
  14. Confirming positive lateral flow test results with PCR tests is important, in part
    because it allows samples to be obtained for sequencing.
    ACTION: COG-UK, NHSE and NHSTT to consider potential options to increase proportion
    of samples from hospitals which are sequenced.
    ACTION: PHE to continue to prioritise control of variants and policymakers to factor risk into
    policy choices.
    Vaccine updates and efficacy against new variants
  15. SARS-CoV-2 is evolving antigenically (high confidence). Some variants are less well
    neutralized by antibodies raised to current vaccines, and the vaccine efficacy against
    these variants is lower than for the existing predominant virus. There is therefore a
    need for medium and long-term strategies for vaccination.
  16. Administration of further doses of current vaccines, which are based on the spike
    protein from the Wuhan-like virus that emerged in 2019, might maintain and/or boost
    protection into winter 2021/22, but potentially less so for individuals with a less robust
    immune response, and less so if substantially antigenically variant viruses circulate
    widely.
  17. Eventually it is likely that the virus will display substantial antigenic variation and
    current vaccines may fail to protect against transmission, infection, or even against
    disease caused by newer variants. Updating the vaccine to keep pace with viral
    evolution or searching for more broadly protective vaccines are potential solutions to
    this.
  18. There are some things which can be learnt from the approach to updating influenza
    vaccines, including the potential to account for prior immunity in optimising vaccine
    choice. However, there will be differences between SARS-CoV-2 and influenza, and
    so not all of the findings from the latter will necessarily be applicable.
  19. Effective vaccine updates will require coordinated virus and immunity surveillance,
    which has been a strength of the UK so far, but this will also need to be linked to
    serology, immunology, structural biology, and viral phenotyping. The UK should build
    on what it has developed during the pandemic to create a sustainable hub for this.
    ACTION: UKHSA to work with Wendy Barclay, Derek Smith and other relevant groups to
    outline the requirements for academic input into the system for surveillance and vaccine
    update. A sustainable structure is required.
    Roadmap Modelling
  20. Modelling shows that taking step 3 of the roadmap is alone highly unlikely to put
    unsustainable pressure on the NHS. It is however likely to lead to R being greater
    than 1 in England and therefore an increase in infections. The full impact on
    hospitalisations and deaths will not be seen until mid-June at the earliest.
  21. Modelling of both step 3 and step 4 (based on the earliest possible date for each)
    shows that it remains highly likely that there will be a further resurgence in
    hospitalisations and deaths, however, the scale, shape, and timing remain highly
    uncertain.
  22. In most scenarios modelled, any peak in numbers of hospitalisations and deaths is
    smaller than any previous wave seen in England. The peaks are also smaller than
    modelled ahead of step 2 because new evidence suggests that vaccination may
    have a greater impact on transmission than previously assumed, including by
    reducing the extent to which vaccinated people who become infected then infect
    others. There has also been continued high uptake of vaccination which has
    contributed to the improved situation.
  23. The resurgence will be smaller if baseline measures and sustained changes in
    behaviour which reduce transmission are maintained beyond the end of the roadmap
    (high confidence). The speed of vaccine rollout is also a key factor in the size of the
    resurgence (high confidence). The two biggest risks (absent new variants) are that
    either high contact patterns emerge early, or there is low vaccine rollout amongst
    younger adults. The combination of these two would lead to a larger resurgence.
  24. If baseline policies to reduce transmission are kept in place at the end of the
    roadmap, behaviour does not return to pre-pandemic levels, and vaccine rollout is
    not substantially slowed, there is an opportunity to keep the resurgence small.
    Modelling of a gradual easing after step 4 shows a smaller resurgence than a faster
    one, as it allows more people to have been vaccinated before R increases. If there
    were to be a return to pre-pandemic behaviours, delaying this until as many people
    as possible had been vaccinated would be highly beneficial.
  25. SAGE has previously provided advice on baseline measures (SAGE 87). In
    particular, immediate isolation on symptom onset or a positive test is a particularly
    effective measure if adherence is high, and there is scope to increase the
    effectiveness of this.
  26. A variant which either substantially escapes immunity or is highly transmissible (more
    so than B.1.1.7) could lead to a very significant wave of infection, potentially larger
    than that seen in January 2021 if there were no interventions. Given the uncertainty
    around the properties of any such variant this modelling is based on some illustrative
    scenarios only. The central scenarios modelled do not include any impact from new
    variants. Reducing the number of variant infections should be a priority for policy.
  27. Maintaining control of transmission of any such variants will be more difficult when
    there are fewer measures in place. The extinction probability of a cluster depends
    heavily on the size of the cluster when it is identified, and the number of clusters will
    increase with the rate of importation. It would therefore be worthwhile to target
    resources at early detection of clusters of variants, particularly as potential
    importations increase. The principles of responding quickly, taking strong measures,
    and doing so over a wider geography than where the issue has been identified
    should apply.
  28. There remain several sources of uncertainty in the modelling, including around the
    behavioural response to changes in policy (after both step 3 and step 4), the impact
    of any seasonal variation in transmission, the extent of waning immunity, vaccine
    rollout speed, and the impact of vaccination on transmission (including from
    asymptomatic infected people). Analysis from one model indicates that the outcomes
    would be expected to be worse if immunity does wane.
  29. Seasonal variation in activities including education terms and international travel
    patterns will affect transmission and may affect the potential for introductions of new
    variants. Particular consideration may be needed around the start of university terms
    in the Autumn including with respect to international travel to universities.
    ACTION: ONS to consider using infection survey to estimate impact of vaccination on
    transmission from both symptomatic and asymptomatic infected people.
    ACTION: SAGE participants to advise ONS of any questions which it would be useful to
    add to regular surveys.
    List of actions
    COG-UK, NHSE and NHSTT to consider potential options to increase proportion of samples
    from hospitals which are sequenced.
    PHE to continue to prioritise control of variants and policymakers to factor risk into policy
    choices.
    UKHSA to work with Wendy Barclay, Derek Smith and other relevant groups to outline the
    requirements for academic input into the system for surveillance and vaccine update. A
    sustainable structure is required.
    ONS to consider using infection survey to estimate impact of vaccination on transmission
    from both symptomatic and asymptomatic infected people.
    SAGE participants to advise ONS of any questions which it would be useful to add to
    regular surveys.
    Attendees
    Scientific experts (38): Patrick Vallance (GCSA), Chris Whitty (CMO), Angela McLean
    (MoD, CSA), Catherine Noakes (Leeds), Calum Semple (Liverpool), Charlotte Deane
    (UKRI), Charlotte Watts (FCDO, CSA), Derek Smith (Cambridge), Fliss Bennee (Welsh
    Government), Graham Medley (LSHTM), Harry Rutter (Bath), Ian Boyd (St. Andrewes), Ian
    Diamond (ONS), Ian Hall (SCGW), Ian Young (Northern Ireland, Health CSA), James
    Rubin (KCL), Jeanelle de Gruchy (ADPH), Jennet Woolford (ONS), Jenny Harries (UKHSA),
    Jeremy Farrar (Wellcome), John Edmunds (LSHTM), Jonathan Van Tam (dCMO), Kamlesh
    Khunti (Leicester), Linda Partridge (Royal Society), Lucy Yardley (Bristol/Southampton),
    Maria Zambon (PHE) Mark Walport (UKRI), Mark Wilcox (Leeds), Michael Parker (Oxford),
    Meera Chand (PHE), Nicola Steedman (Scottish Government, dCMO), Peter Horby
    (Oxford), Rob Orford (Welsh Government, Health CSA), Sharon Peacock (PHE), Steve
    Powis (NHS England), Susan Hopkins (PHE/NHST&T), Wei Shen Lim (Nottingham), and
    Wendy Barclay (Imperial).
    Observers and government officials (22): Alan Penn (MHCLG, CSA), Andrew Curran
    (HSE, CSA), , Ben Warner (No.10), Christopher Williams (PHW), Daniel
    Kleinberg (Scottish Government), David Lamberti (DHSC), Fergus Cumming (DHSC/JBC),
    Giri Shankar (PHW), James Benford (HMT), Jennifer Rubin (HO, CSA), Jim McMenamin
    (Health Protection Scotland), Julian Fletcher (CO), , Liz Lalley
    (Welsh Government), , Osama Rahman (DfE, CSA),
    , Paul Monks (BEIS, CSA), Phil Blythe (DfT, CSA), Rob Harrison (CO) and
    .
    Secretariat (all GO-Science) (16): , , ,
    , , , , ,
    , , , , Simon Whitfield, Stuart Wainwright,
    and Zoe Bond.

MINUTES HERE

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