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HEALTH

The Claim

The SARS-CoV-2 Omicron XBB subvariant is lethal and is not easy to detect.

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The Short Version

The claim overstates both the danger and the diagnostic difficulty of XBB. Authoritative human data show XBB was not unusually deadly compared with other Omicron lineages, even though severe illness and death could still occur in high-risk people. Standard COVID-19 tests continued to detect XBB; only some specific assay targets or variant-tracking markers were affected.

Caveats

  • “Not especially lethal” does not mean harmless: XBB could still cause hospitalization and death, particularly in older or immunocompromised people.
  • Some mutations can reduce performance of specific test targets or complicate variant identification, but that is not the same as standard PCR or antigen tests failing to detect infection.
  • The claim uses broad, unqualified language; without specifying relative severity, population risk, or which test method is meant, it misleads about both danger and detectability.

The Receipts

  1. XBB.1.5 Updated Risk Assessment, 24 February 2023

    World Health Organization

  2. Spike Gene Target Amplification in a Diagnostic Assay as a Marker for Omicron Sublineages

    CDC

  3. Mortality Risk Among Patients Hospitalized Primarily for COVID-19 During the Omicron Variant Predominance Compared with the Delta Variant Predominance — National Hospital Care Survey, United States, July 2021–June 2022

    Centers for Disease Control and Prevention

  4. Early Estimates of Updated 2023–2024 (Monovalent XBB.1.5) COVID-19 Vaccine Effectiveness in Preventing Symptomatic SARS-CoV-2 Infection

    Centers for Disease Control and Prevention (CDC)

  5. Effectiveness of Updated 2023–2024 (Monovalent XBB.1.5) COVID-19 Vaccination Against SARS-CoV-2 Omicron XBB and BA.2.86/JN.1 Lineage Hospitalization and a Comparison of Clinical Severity—IVY Network, 26 Hospitals, October 18, 2023–March 9, 2024

    National Library of Medicine (PMC)

  6. Overview of Testing for SARS-CoV-2 (COVID-19)

    Centers for Disease Control and Prevention

  7. Does the COVID-19 XBB Omicron subvariant signal the beginning of endemicity?

    Singapore Medical Journal (via PubMed Central)

  8. S-Gene Target Failure as an Effective Tool for Tracking the Emergence of Dominant SARS-CoV-2 Variants in Switzerland and Liechtenstein

    National Institutes of Health (PMC)

  9. S-Gene Target Failure as an Effective Tool for Tracking the Emergence of Dominant SARS-CoV-2 Variants in Switzerland and Liechtenstein

    PubMed

  10. SARS-CoV-2 Viral Mutations: Impact on COVID-19 Tests

    U.S. Food and Drug Administration

+ 22 more sources — see the full list on Lenz

Filed Under

COVID-19 virusOmicronXBB

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