SPI-M-O: Consensus statement on COVID-19, 17 September 2020
Consensus statement from the Scientific Pandemic Influenza Group on Modelling, Operational sub-group (SPI-M-O) for the Scientific Advisory Group for Emergencies (SAGE).
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Consensus statement from SPI-M-O on COVID-19. It was considered at SAGE 57 on 17 September 2020.
The paper is the assessment of the evidence at the time of writing. As new evidence or data emerges, SAGE updates its advice accordingly.
This paper should be read alongside the SPI-M-O: Consensus statement on COVID-19 and accompanying paper, ‘Circuit breakers - implementing (partial) lockdown for 2 weeks over half-term’, as released under SAGE 59.
This paper contains estimates of the reproduction number (R) and growth rate for the UK, 4 nations and NHS England (NHSE) regions.
Different modelling groups use different data sources to estimate these values using mathematical models that simulate the spread of infections. Some may even use all these sources of information to adjust their models to better reflect the real-world situation. There is uncertainty in all these data sources, which is why estimates can vary between different models, and why we do not rely on one model; evidence from several models is considered, discussed, combined, and the growth rate and R are then presented as ranges.
See the latest R number and growth rates, and further background.
This paper also includes estimates of the change in pillar 2 test positivity in England. Please note that trends in this data are difficult to interpret due to changes in testing behaviour and testing strategies, particularly in areas of local intervention where testing volumes have increased.
We cannot tell how much this represents a true change in the number of infections, and how much arises from changes in targeting of pillar 2 testing in terms of specific geographic locations or age groups with higher or lower prevalence. Recent developments around NHS T&T capacity and testing delays have increased this uncertainty.
This paper references a reasonable worst-case planning scenario (RWCS). RWCS should not be interpreted as a forecast or prediction of what is most likely to happen. They do not represent the full range of possible outcomes and no likelihood is attached to these scenarios.
This paper also references pilot medium-term projections in development. Please note that these are projections based on current trends assuming no further policy or behavioural changes occur, and should not be interpreted as forecasts or predictions. They do not include the impact of any measures that were not yet reflected in observed data, including any national and local measures introduced in the 2 weeks prior, or any future changes that might be implemented.
These documents are released as pre-print publications that have provided the government with rapid evidence during an emergency. These documents have not been peer-reviewed and there is no restriction on authors submitting and publishing this evidence in peer-reviewed journals.