https://www.medrxiv.org/content/10.1101/2022.01.11.22269045v1
The Omicron (B.1.1.529) variant of SARS-CoV-2 has rapidly achieved global dissemination,
accounting for most infections in the United States by December 2021.
November 30, 2021 to January 1, 2022, Delta v Omicron
Using S gene target failure (SGTF) (99.7%)
Hospital admission
Lengths of hospital stay
Hospital admissions associated with new-onset respiratory symptoms
Intensive care unit (ICU) admission
Mechanical ventilation
Mortality
Group 1, omicron
N = 52,297, cases with Omicron variant infections
Hospital admissions, 235 (0.5%)
Mean follow-up, 5.5 days
88 admitted
ITU, 7
Ventilated, 0
Deaths, 1
Length of hospital stay, 3.4 days (70%) less than delta
Group 2, non – omicron (delta)
N = 16,982, cases with Delta variant infections
Hospital admissions, 222 (1.3%)
Mean follow-up, 15.8 days
189 admitted
ITU, 23
Ventilated, 11
Deaths, 14
Also
Omicron variant infection, reduced risk of hospitalization across age and comorbidity categories
Risk of symptomatic hospitalization was markedly reduced among cases who had tested positive for SARS-CoV-2 infection ≥90 days prior
Intrinsically less severe infection
Less severe in vaccinated and unvaccinated
Evidence for a reduction in severe outcomes among vaccinated cases with both Delta and Omicron variant infections in our study suggests substantial public health benefits from continued COVID-19 vaccination.
Dutch data
https://twitter.com/marionkoopmans/status/1472470129350955012
Common cold protection
https://www.imperial.ac.uk/news/233018/cells-from-common-colds-cross-protect-against/
Cross-reactive memory T cells associate with protection against SARS-CoV-2 infection in COVID-19 contacts
https://www.nature.com/articles/s41467-021-27674-x
52 COVID-19 household contacts
We enumerate the frequency of specific T cells
Spike, nucleocapsid, membrane, envelope and ORF1,
that cross-react with human endemic coronaviruses
Nucleocapsid-specific T cells
Limited protective function of spike-cross-reactive T cells
Our results are thus consistent with,
pre-existing non-spike cross-reactive memory T cells,
protecting SARS-CoV-2-naïve contacts from infection,
thereby supporting the inclusion of non-spike antigens in second-generation vaccines.