OMICRON VARIANT

Dec. 29, 2021

Please see the attached E-book for:

 

“Investigation of a SARS-CoV-2 B.1.1.529 (Omicron) Variant Cluster — Nebraska, November–December 2021”

Link when live: https://www.cdc.gov/mmwr/volumes/70/wr/mm705152e3.htm?s_cid=mm705152e3_w

Dec. 27, 2021


CDC Updates and Shortens Recommended Isolation and Quarantine Period for General Population

Given what we currently know about COVID-19 and the Omicron variant, CDC is shortening the recommended time for isolation from 10 days for people with COVID-19 to 5 days, if asymptomatic, followed by 5 days of wearing a mask when around others. The change is motivated by science demonstrating that the majority of SARS-CoV-2 transmission occurs early in the course of illness, generally in the 1-2 days prior to onset of symptoms and the 2-3 days after. Therefore, people who test positive should isolate for 5 days and, if asymptomatic at that time, they may leave isolation if they can continue to mask for 5 days to minimize the risk of infecting others.



Additionally, CDC is updating the recommended quarantine period for those exposed to COVID-19. For people who are unvaccinated or are more than six months out from their second mRNA dose (or more than 2 months after the J&J vaccine) and not yet boosted, CDC now recommends quarantine for 5 days followed by strict mask use for an additional 5 days. Alternatively, if a 5-day quarantine is not feasible, it is imperative that an exposed person wear a well-fitting mask at all times when around others for 10 days after exposure. Individuals who have received their booster shot do not need to quarantine following an exposure, but should wear a mask for 10 days after the exposure. For all those exposed, best practice would also include a test for SARS-CoV-2 at day 5 after exposure. If symptoms occur, individuals should immediately quarantine until a negative test confirms symptoms are not attributable to COVID-19.



Isolation relates to behavior after a confirmed infection. Isolation for 5 days followed by wearing a well-fitting mask will minimize the risk of spreading the virus to others. Quarantine refers to the time following exposure to the virus or close contact with someone known to have COVID-19. Both updates come as the Omicron variant continues to spread throughout the U.S. and reflects the current science on when and for how long a person is maximally infectious.



Data from South Africa and the United Kingdom demonstrate that vaccine effectiveness against infection for two doses of an mRNA vaccine is approximately 35%. A COVID-19 vaccine booster dose restores vaccine effectiveness against infection to 75%. COVID-19 vaccination decreases the risk of severe disease, hospitalization, and death from COVID-19. CDC strongly encourages COVID-19 vaccination for everyone 5 and older and boosters for everyone 16 and older. Vaccination is the best way to protect yourself and reduce the impact of COVID-19 on our communities.



The following is attributable to CDC Director, Dr. Rochelle Walensky:


“The Omicron variant is spreading quickly and has the potential to impact all facets of our society. CDC’s updated recommendations for isolation and quarantine balance what we know about the spread of the virus and the protection provided by vaccination and booster doses. These updates ensure people can safely continue their daily lives. Prevention is our best option: get vaccinated, get boosted, wear a mask in public indoor settings in areas of substantial and high community transmission, and take a test before you gather.”

Dec. 18, 2021

Enhancing Readiness for Omicron (B.1.1.529): Technical Brief and Priority Actions for Member States

Enhancing Readiness for Omicron (B.1.1.529): Technical Brief and Priority Actions for Member States (who.int)

Overview

  • On 26 November 2021, WHO designated the variant B.1.1.529 a variant of concern (VOC), on the basis of advice from WHO’s Technical Advisory Group on Virus Evolution. The variant has been given the name Omicron. Omicron variant is a highly divergent variant with a high number of mutations, including 26-32 in the spike protein, some of which are concerning and may be associated with humoral immune escape potential and higher transmissibility.
  • As of 16 December 2021, the Omicron variant has been identified in 89 countries across all six WHO regions. Current understanding of the Omicron variant will continue to evolve as more data becomes available.
  • The overall threat posed by Omicron largely depends on four key questions, including: (1) how transmissible the variant is; (2) how well vaccines and prior infection protect against infection, transmission, clinical disease and death; (3) how virulent the variant is compared to other variants; and (4) how populations understand these dynamics, perceive risk and follow control measures, including public health and social measures. Public health advice is based on current information and will be tailored as more evidence emerges around those key questions.
  • There is consistent evidence that Omicron has a substantial growth advantage over Delta. It is spreading significantly faster than the Delta variant in countries with documented community transmission, with a doubling time between 1.5–3 days. Omicron is spreading rapidly in countries with high levels of population immunity and it remains uncertain to what extent the observed rapid growth rate can be attributed to immune evasion, intrinsic increased transmissibility or a combination of both. However, given current available data, it is likely that Omicron will outpace Delta where community transmission occurs.
  • There are still limited data on the clinical severity of Omicron. More data are needed to understand the severity profile and how severity is impacted by vaccination and pre-existing immunity. Hospitalizations in the UK and South Africa continue to rise, and given rapidly increasing case counts, it is possible that many healthcare systems may become quickly overwhelmed.
  • Preliminary data suggest that there is a reduction in neutralizing titres against Omicron in those who have received a primary vaccination series or in those who have had prior SARS-CoV-2 infection , which may suggest a level of humoral immune evasion.
  • There are still limited available data, and no peer-reviewed evidence, on vaccine efficacy or effectiveness to date for Omicron. Preliminary findings of vaccine effectiveness studies (test-negative design) were obtained from South Africa and England, the United Kingdom. Available preliminary data to be interpreted with caution as the designs may be subject to selection bias and the results are based on relatively small numbers. Results from England indicate a significant reduction in vaccine effectiveness against symptomatic disease for Omicron compared to Delta after two vaccine doses of either Pfizer BioNTech-Comirnaty or AstraZeneca-Vaxzevria vaccines. There was, however,  higher effectiveness two weeks after a Pfizer BioNTech-Comirnaty booster, which was slightly lower or comparable to that against Delta. A non peer-reviewed study by South Africa researchers using private health insurance data reported reductions in vaccine effectiveness of the Pfizer BioNTech-Comirnaty vaccine against infection, and to a lesser degree against hospitalization.  Details about the methods or results were not available at the time of writing.
  • The diagnostic accuracy of routinely used PCR and antigen-based rapid diagnostic test (Ag-RDT) assays does not appear to be impacted by Omicron. Most Omicron variant sequences reported include a deletion in the S gene, which can cause an S gene target failure (SGTF) in some PCR assays. Though a minority of publicly-shared sequences lack this deletion, SGTF can be used as a proxy marker to screen for Omicron. However, confirmation should be obtained by sequencing, as this deletion can also be found in other VOCs (e.g. Alpha and subsets of Gamma and Delta) circulating at low frequencies globally.
  • Therapeutic interventions for the management of patients with severe or critical COVID-19 associated with the Omicron variant that target host responses (such as corticosteroids, and interleukin 6 receptor blockers) are expected to remain effective.  However, preliminary data from preprint publications suggest that some of the monoclonal antibodies developed against SARS-CoV-2 may have decreased neutralization against Omicron. Monoclonal antibodies will need to be tested individually for their antigen binding and virus neutralization, and these studies should be prioritized

To read the full document, click here: 

Enhancing Readiness for Omicron (B.1.1.529): Technical Brief and Priority Actions for Member States (who.int)

To view previous versions of this technical brief, please see the links below. The current version of all WHO information products and publications is authoritative.

28 November 2021 (updated 29 November with minor editorial corrections)

10 December 2021 (updated from the last version published on 28 November 2021)

 

Dec. 3, 2021

 

 

 

CDC is working with the Minnesota Department of Health and the New York City Department of Health and Mental Hygiene to investigate a confirmed case of COVID-19 caused by the Omicron variant. The individual, a resident of Minnesota, developed mild symptoms on November 22 and sought COVID-19 testing on November 24. The person has since recovered. The individual traveled to New York City and attended the Anime NYC 2021 convention at the Javits Center from November 19-21, 2021.

 

CDC recommends people follow COVID-19 prevention strategiesEveryone 5 years and older should get vaccinated and get a booster shot, if recommended. Get tested if you have symptoms and stay home if you are sick.

 

The following is attributable to CDC Director, Dr. Rochelle Walensky

“CDC has been actively monitoring and preparing for this variant. We have been working closely with Minnesota’s Department of Health and will continue to work diligently with other U.S. and global public health and industry partners as we learn more. CDC has expanded its capacity for genomic sequencing over the past nine months and we have more tools to fight the variant than we had at this time last year from vaccines to boosters to the prevention strategies that we know work including masking in indoor public settings, washing your hands frequently and physical distancing. These methods work to prevent the spread of COVID-19, no matter the genetic sequence.”

 

Dec. 1, 2021

First confirmed case of Omicron variant detected in the United States

 

The California and San Francisco Departments of Public Health have confirmed that a recent case of COVID-19 among an individual in California was caused by the Omicron variant (B.1.1.529). The individual was a traveler who returned from South Africa on November 22, 2021. The individual, who was fully vaccinated and had mild symptoms that are improving, is self-quarantining and has been since testing positive. All close contacts have been contacted and have tested negative.

 

Genomic sequencing was conducted at the University of California, San Francisco and the sequence was confirmed at CDC as being consistent with the Omicron variant. This will be the first confirmed case of COVID-19 caused by the Omicron variant detected in the United States. 

 

On November 26, 2021, the World Health Organization (WHO) classified a new variant, B.1.1.529, as a Variant of Concern and named it Omicron and on November 30, 2021, the United States also classified it as a Variant of Concern. CDC has been actively monitoring and preparing for this variant, and we will continue to work diligently with other U.S. and global public health and industry partners to learn more. Despite the detection of Omicron, Delta remains the predominant strain in the United States.

 

The recent emergence of the Omicron variant (B.1.1.529) further emphasizes the importance of vaccination, boosters, and general prevention strategies needed to protect against COVID-19. Everyone 5 and older should get vaccinated boosters are recommended for everyone 18 years and older.  

 

For more information on the Omicron variant visit https://www.cdc.gov/coronavirus/2019-ncov/variants/index.html.