Summary
1. SPI-M-O's best estimate for R in England is between 0.8 and 1.1. R is estimated to be between 0.8 and 1.0 for Scotland, 0.7 and 1.0 for Wales, and 0.8 and 1.1 for Northern Ireland. These estimates are based on the data available up to 10th May, including hospitalisations and deaths as well as symptomatic testing and prevalence studies.
2. Overall, the epidemic in England could be either flat, shrinking slowly, or growing slightly. There are local areas in all nations where the epidemic is increasing and some localities, such as parts of the North West and Bedford, have fast growth of S-gene positive variants that is concerning. This includes the B.1.617.2 variant.
3. Clusters of such new variants mean it is becoming more difficult to interpret R estimates as they are averages over populations, viral variants and areas. Situations could change quickly, especially as restrictions are relaxed further from 17th May.
4. SPI-M-O estimates that there are between 1,000 and 7,000 new infections per day in England.
5. The number and proportion of cases that are S-gene positive continues to increase and this is highly heterogeneous across regions and ethnicities. SPI-M-O is confident that B.1.617.2 is more transmissible than B.1.1.7, and it is a realistic possibility that this new variant of concern could be 50% more transmissible. If B.1.617.2 does have such a large transmission advantage, it is a realistic possibility that progressing with all Roadmap steps would lead to a substantial resurgence of hospitalisations.
6. SPI-M-O has also considered the merits of surge vaccination. While the impact of such a programme is uncertain, from a non-operational epidemiological perspective alone, it has a large potential upside and relatively small potential drawbacks with regard to transmission.