#16,408
With the strong caveat that we continue to learn new information about the Omicron variant practically every day, and the numbers of confirmed cases changes by the hour, yesterday the CDC's MMWR published a detailed summary of what we know - or at least think we know - to date.
Due to its length I've only included the link, summary, introduction, and discussion from the report. Follow the link to read it in its entirety.SARS-CoV-2 B.1.1.529 (Omicron) Variant — United States, December 1–8, 2021
Early Release / December 10, 2021 / 70
CDC COVID-19 Response Team (View author affiliations)
Summary
What is already known about this topic?
SARS-CoV-2 variant B.1.1.529 (Omicron), first reported to WHO on November 24, 2021, has been designated a variant of concern. Mutations in Omicron might increase transmissibility, confer resistance to therapeutics, or partially escape infection- or vaccine-induced immunity.
What is added by this report?
During December 1–8, 2021, 22 U.S. states reported at least one COVID-19 case attributed to the Omicron variant. Among 43 cases with initial follow-up, one hospitalization and no deaths were reported.
What are the implications for public health practice?
Implementation of concurrent prevention strategies, including vaccination, masking, improving ventilation, testing, quarantine, and isolation are recommended to slow transmission of SARS-CoV-2, including variants such as Omicron, to protect against severe illness and death from COVID-19.
A new variant of SARS-CoV-2 (the virus that causes COVID-19), B.1.1.529 (Omicron) (1), was first reported to the World Health Organization (WHO) by South Africa on November 24, 2021. Omicron has numerous mutations with potential to increase transmissibility, confer resistance to therapeutics, or partially escape infection- or vaccine-induced immunity (2). On November 26, WHO designated B.1.1.529 as a variant of concern (3), as did the U.S. SARS-CoV-2 Interagency Group (SIG)* on November 30. On December 1, the first case of COVID-19 attributed to the Omicron variant was reported in the United States.
As of December 8, a total of 22 states had identified at least one Omicron variant case, including some that indicate community transmission. Among 43 cases with initial follow-up, one hospitalization and no deaths were reported. This report summarizes U.S. surveillance for SARS-CoV-2 variants, characteristics of the initial persons investigated with COVID-19 attributed to the Omicron variant and public health measures implemented to slow the spread of Omicron in the United States. Implementation of concurrent prevention strategies, including vaccination, masking, increasing ventilation, testing, quarantine, and isolation, are recommended to slow transmission of SARS-CoV-2, including variants such as Omicron, and to protect against severe illness and death from COVID-19.
(SNIP)
Discussion
The first U.S. case of COVID-19 attributed to the Omicron variant was detected on December 1, 2021. Among the cases described in this report, the earliest report of symptom onset was November 15. For the week ending December 4, the Delta variant accounted for >99.9% of circulating SARS-CoV-2 variants. Given the 2–3 weeks from the time of specimen collection to availability of sequence data for analysis, it is likely that additional infections with Omicron from late November will be detected during the coming days. Scientists around the world are working to rapidly learn more about the Omicron variant to better understand how easily it might be transmitted and the effectiveness of current diagnostic tests, vaccines, and therapeutics against this variant.
Many of the first reported cases of Omicron variant infection appear to be mild (7), although as with all variants, a lag exists between infection and more severe outcomes, and symptoms would be expected to be milder in vaccinated persons and those with previous SARS-CoV-2 infection than in unvaccinated persons. Characteristics of the cases described in this report might also not be generalizable because case findings might be associated with individual characteristics (e.g., persons with recent international travel might be more likely to be younger and vaccinated). Even if most infections are mild, a highly transmissible variant could result in enough cases to overwhelm health systems.
The clinical severity of infection with the Omicron variant will become better understood as additional cases are identified and investigated. Scientists in South Africa and elsewhere have established systems that allow study of the laboratory, clinical, and epidemiologic characteristics; CDC is collaborating with health officials around the world to learn more about the characteristics of patients with Omicron variant infections.
The rapid emergence and worldwide detection of the SARS-CoV-2 Omicron variant underscores the importance of robust genomic surveillance systems and prompt information-sharing among global public health partners. During the past several years, CDC has intensified efforts to significantly expand genomic sequencing capacity at the federal and state levels. Through these investments, an average of 50,000–60,000 positive specimens are sequenced weekly as part of national SARS-CoV-2 genomic surveillance, which assisted with identifying initial cases of COVID-19 attributed to the Omicron variant in the United States.
A number of measures have been implemented throughout the COVID-19 pandemic to reduce the introduction and spread of SARS-CoV-2 in the United States through travel. For example, masks are required in indoor areas on public transportation conveyances traveling into, within, or out of the United States, and on the indoor premises of U.S. transportation hubs.¶¶¶ Current travel requirements and recommendations,**** surveillance programs, and efforts to educate travelers are intended to reduce COVID-19 transmission and support safer global travel. CDC is also supporting efforts to prevent, detect, and respond to COVID-19 internationally, including through support for laboratory and sequencing capacity and strengthening global vaccine programs.
Implementation of concurrent prevention strategies, including vaccination, masking, improving ventilation, testing, quarantine, and isolation, are recommended to slow transmission of SARS-CoV-2 and to protect against severe illness, hospitalization, and death from COVID-19. All persons aged ≥5 years should be vaccinated against COVID-19. Persons aged ≥18 years who completed a primary mRNA COVID-19 vaccination series ≥6 months previously or who received an initial Janssen (Johnson & Johnson) vaccine dose ≥2 months previously should receive a booster dose; persons aged 16–17 years are eligible to receive a Pfizer-BioNTech COVID-19 booster dose >6 months after completion of the primary series. Booster doses are especially urgent for those at higher risk of severe disease, such as persons residing in nursing homes and long-term care facilities. In addition, CDC recommends that everyone aged ≥2 years wear masks in public indoor places in areas of substantial or high transmission.
Acknowledgments
Public health departments and laboratories in Arizona, California (including Alameda County, Los Angeles, and San Francisco), Colorado, Connecticut, Florida, Georgia, Hawaii, Illinois, Louisiana, Maryland, Massachusetts, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, New York, (including New York City), Pennsylvania, Texas, Utah, Washington, and Wisconsin.
