NIESR Weekly Covid-19 Tracker: Reproduction Number (R) and Forecasts of New Cases: Admissions and Deaths to Reduce Rapidly

Publication date: 4 Mar 2021 | Publication type: NIESR Covid-19 Tracker | NIESR Author(s): Thamotheram, C Issue 3

Reproduction Number (R) and Forecasts of New Cases: Admissions and Deaths to Reduce Rapidly

Main points

  • The NIESR estimates use a new time series model to project new cases of Covid-19 and produce timely estimates of the R number.  In addition, we also produce forecasts of hospital admissions and deaths due to Covid-19. The forecasts reported here were made using publicly available data on 2nd March 2021.
  • Figure 1 shows that the Reproduction number, R, which is the average number of secondary infections currently generated by an infected individual, returned to 0.75 – 0.85 by the end of February from a range of 0.9 – 1.0 where it had been the week before.
  • Should these pandemic variables in the UK continue to fall at the current rate, by 8th March when schools reopen, trend daily cases are forecast to be around 4,300, hospital admissions around 600 and number of deaths close to 200 (Figures 2-4).
  • Looking further ahead to when non-essential retail is scheduled to reopen on the 12th April, we expect trend daily cases to be around 700, admissions around 200 and deaths below 50 (Figures 2-4). To the extent that the re-opening increases transmission these numbers are likely to increase. On the other hand, these numbers could decrease to the extent that the vaccination programme reduces transmission. It will be interesting to see which of these effects dominate in the subsequent data.
  • Figure 5 shows that all regional R number estimates are again below one, which was not the case last week. Currently, the South West has the lowest R number while Northern Ireland and Yorkshire and the Humber again have the highest.

“According to the latest data on new cases, our work shows an R number for the UK in the range 0.75 – 0.85, taking it back to the range that it has been in since mid-January. Interestingly, our model forecasts for admissions and deaths were revised downwards through to early February, settling later than those for new cases. This may be due to the reduction in cases from reduced mobility during lockdown translating into subsequent reductions in admissions and deaths with a lag. Our forecasts of pandemic variables sit well with recent evidence on the efficacy of the first dose of the vaccine in protecting against symptomatic Covid-19 for the over 70s, consequently reducing admissions and deaths as vaccines have been rapidly rolled-out since early 2021.”