Projected epidemiological consequences of the Omicron SARS-CoV-2 variant in England, December 2021 to April 2022

  1. Rosanna C. Barnard
  2. Nicholas G. Davies
  3. Carl A. B. Pearson
  4. Mark Jit
  5. W. John Edmunds

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Abstract

The Omicron B.1.1.529 SARS-CoV-2 variant was first detected in late November 2021 and has since spread to multiple countries worldwide. We model the potential consequences of the Omicron variant on SARS-CoV-2 transmission and health outcomes in England between December 2021 and April 2022, using a deterministic compartmental model fitted to epidemiological data from March 2020 onwards. Because of uncertainty around the characteristics of Omicron, we explore scenarios varying the extent of Omicron’s immune escape and the effectiveness of COVID-19 booster vaccinations against Omicron, assuming the level of Omicron’s transmissibility relative to Delta to match the growth in observed S gene target failure data in England. We consider strategies for the re-introduction of control measures in response to projected surges in transmission, as well as scenarios varying the uptake and speed of COVID-19 booster vaccinations and the rate of Omicron’s introduction into the population. These results suggest that Omicron has the potential to cause substantial surges in cases, hospital admissions and deaths in populations with high levels of immunity, including England. The reintroduction of additional non-pharmaceutical interventions may be required to prevent hospital admissions exceeding the levels seen in England during the previous peak in winter 2020–2021.

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    SciScore for 10.1101/2021.12.15.21267858: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    We assume that individuals in the recovered disease state who have previously been infected with SARS-CoV-2 have the same level of protection against Omicron as individuals who have received two doses of Pfizer/Moderna.
    SARS-CoV-2
    suggested: (BioLegend Cat# 946101, RRID:AB_2892515)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Our work is subject to limitations. We do not account for the differing rate of Omicron introduction to each NHS England region, and we do not consider the impact of localised interventions. We do not capture the potential impact of newly available antiviral therapies, or the future availability of targeted vaccines for Omicron, but nor do we consider that some existing therapies (such as monoclonal antibodies) may become less effective given the escape properties of Omicron. We assume that the baseline infection fatality rate (IFR) remains constant over the projection period (except as altered by, e.g., primary and/or booster vaccination uptake), though our model fit suggests the IFR may increase during periods of high strain on hospital services (Fig. S1). We only report burdens during the period 1st December 2021 to 30 April 2022, because of uncertainty over what additional measures may be available to mitigate Omicron by mid-2022—for example, reformulated vaccines. However, our scenarios with more stringent control measures enacted between December 2021 to April 2022 result in larger exit waves after control measures are lifted. Finally, the control measures we consider are limited and are based on the known impacts of previously implemented control strategies for SARS-CoV-2 in England. Implementing strategies such as enhanced mass testing may help to reduce the required stringency of non-pharmaceutical interventions aimed at reducing interpersonal contact rates. Accordin...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a protocol registration statement.

    Results from scite Reference Check: We found no unreliable references.

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  2. Version published to 10.1101/2021.12.15.21267858v1 on medRxiv