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. 2022 Feb;22(2):69-71.
doi: 10.1038/s41577-022-00678-4.

Milder disease with Omicron: is it the virus or the pre-existing immunity?

Alex Sigal  1   2   3
Affiliations

Milder disease with Omicron: is it the virus or the pre-existing immunity?

Alex Sigal. Nat Rev Immunol. 2022 Feb.

Abstract

At the population level we are seeing milder disease during the Omicron wave of the SARS-CoV-2 pandemic. Is this due to the virus or pre-existing immunity, and what should we expect next?

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Conflict of interest statement

The author declares no competing interests.

Figures

Fig. 1
Fig. 1. Delta and Omicron waves in South Africa.
The top graphs indicate the number of infections with SARS-CoV-2 and the numbers of patients with COVID-19 who were admitted to intensive care units (ICUs) or placed on ventilation during the course of the pandemic in South Africa (part a). The lower graphs propose how the relative levels of population immunity and viral pathogenicity may have changed. Data collated from the National Institute for Communicable Diseases in South Africa. Parts b and c illustrate how either reduced Omicron pathogenicity (case 1) or increased levels of pre-existing immunity in a population (case 2) can lead to lower levels of severe disease (indicated by dark blue figures).
See this image and copyright information in PMC

References

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Supplementary concepts