1887
Rapid communication Open Access
Like 0

Abstract

In late November 2021, an outbreak of Omicron SARS-CoV-2 following a Christmas party with 117 attendees was detected in Oslo, Norway. We observed an attack rate of 74% and most cases developed symptoms. As at 13 December, none have been hospitalised. Most participants were 30–50 years old. Ninety-six percent of them were fully vaccinated. These findings corroborate reports that the Omicron variant may be more transmissible, and that vaccination may be less effective in preventing infection compared with Delta.

Loading

Article metrics loading...

/content/10.2807/1560-7917.ES.2021.26.50.2101147
2021-12-16
2024-12-11
http://instance.metastore.ingenta.com/content/10.2807/1560-7917.ES.2021.26.50.2101147
Loading
Loading full text...

Full text loading...

/deliver/fulltext/eurosurveillance/26/50/eurosurv-26-50-2.html?itemId=/content/10.2807/1560-7917.ES.2021.26.50.2101147&mimeType=html&fmt=ahah

References

  1. World Health Organization (WHO). Classification of Omicron (B.1.1.529): SARS-CoV-2 Variant of Concern. Geneva: WHO. [Accessed: 6 Dec 2021]. Available from: https://www.who.int/news/item/26-11-2021-classification-of-omicron-(b.1.1.529)-sars-cov-2-variant-of-concern
  2. European Centre for Disease Prevention and Control (ECDC). Threat Assessment Brief: Implications of the further emergence and spread of the SARS CoV 2 B.1.1.529 variant of concern (Omicron) for the EU/EEA first update. Stockholm: ECDC. [Accessed: 6 Dec 2021]. Available from: https://www.ecdc.europa.eu/en/publications-data/covid-19-threat-assessment-spread-omicron-first-update
  3. Norwegian Institute of Public Health (NIPH). Spesifikke TISK-tiltak for omikronvarianten. [Specific testing, isolation, contact tracing and quarantine (TISK) measures for the Omicron variant]. Oslo: FHI. [Accessed: 8 Dec 2021]. Norwegian. Available from: https://www.fhi.no/nettpub/coronavirus/testing/tisk/?term=&h=1#spesifikke-tisktiltak-for-omikronvarianten
  4. United Kingdom Health Security Agency. Risk assessment for SARS-CoV_2 variant: Omicron VOC-21NOV-01 (B.1.1.529). London: UK Health Security Agency. [Accessed: 8 Dec 2021]. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1038442/3_December-2021-risk-assessment-for-SARS_Omicron_VOC-21NOV-01_B.1.1.529.pdf
  5. Brown CM, Vostok J, Johnson H, Burns M, Gharpure R, Sami S, et al. Outbreak of SARS-CoV-2 Infections, Including COVID-19 Vaccine Breakthrough Infections, Associated with Large Public Gatherings - Barnstable County, Massachusetts, July 2021. MMWR Morb Mortal Wkly Rep. 2021;70(31):1059-62.  https://doi.org/10.15585/mmwr.mm7031e2  PMID: 34351882 
  6. Lakdawala SS, Menachery VD. Catch Me if You Can: Superspreading of COVID-19. Trends Microbiol. 2021;29(10):919-29.  https://doi.org/10.1016/j.tim.2021.05.002  PMID: 34059436 
  7. Lemieux JE, Siddle KJ, Shaw BM, Loreth C, Schaffner SF, Gladden-Young A, et al. Phylogenetic analysis of SARS-CoV-2 in Boston highlights the impact of superspreading events. Science. 2021;371(6529):eabe3261.  https://doi.org/10.1126/science.abe3261  PMID: 33303686 
  8. Sekizuka T, Itokawa K, Kageyama T, Saito S, Takayama I, Asanuma H, et al. Haplotype networks of SARS-CoV-2 infections in the Diamond Princess cruise ship outbreak. Proc Natl Acad Sci USA. 2020;117(33):20198-201.  https://doi.org/10.1073/pnas.2006824117  PMID: 32723824 
  9. Norwegian Institute of Public Health (NIPH). Kartlegging av smittesteder for covid-19 i Oslo. [Mapping of community exposures for COVID-19 in Oslo – results of a case-control investigation]. Oslo: FHI. Jun 2021. Norwegian. Available from: https://www.fhi.no/globalassets/dokumenterfiler/rapporter/2021/rapport_kartlegging-av-antatte-smittesteder-i-oslo.pdf
  10. Pulliam JRC, van Schalkwyk C, Govender N, von Gottberg A, Cohen C, Groome MJ, et al. Increased risk of SARS-CoV-2 reinfection associated with emergence of the Omicron variant in South Africa. medRxiv. 2 Dec 2021.  https://doi.org/10.1101/2021.11.11.21266068 
  11. Dyer O. Covid-19: South Africa’s surge in cases deepens alarm over omicron variant. BMJ. 2021;375(3013):n3013.  https://doi.org/10.1136/bmj.n3013  PMID: 34862184 
  12. Centers for Disease Control and Prevention (CDC) COVID-19 Response Team. SARS-CoV-2 B.1.1.529 (Omicron) Variant – United States, December 1-8, 2021. MMWR Morb Mortal Wkly Rep. Atlanta: CDC; 10 Dec 2021. Available from: https://www.cdc.gov/mmwr/volumes/70/wr/mm7050e1.htm
  13. Sundhedspolitisk Tidsskrift. Omicron-smitte efter julefrokost breder sig med lynets hast. [Omicron infection after the Christmas breakfast is spreading fast]. Charlottenlund: Sundhedspolitisk Tidsskrift. 7 Dec 2021. Danish. Available from: https://sundhedspolitisktidsskrift.dk/nyheder/5625-omicron-smitte-efter-julefrokost-breder-sig-med-lynets-hast.html
  14. Grant R, Charmet T, Schaeffer L, Galmiche S, Madec Y, Von Platen C, et al. Impact of SARS-CoV-2 Delta variant on incubation, transmission settings and vaccine effectiveness: Results from a nationwide case-control study in France. The Lancet Regional Health – Europe 2021.  https://doi.org/10.1016/j.lanepe.2021.100278 .
  15. Government of Norway. Strengere nasjonale tiltak for å begrense smitten. [Stricter national control measures in order to reduce the spread]. Press release. 13 Dec 2021. Norwegian. Available from: https://www.regjeringen.no/no/aktuelt/strengere-nasjonale-tiltak-for-a-begrense-smitten/id2892042/
/content/10.2807/1560-7917.ES.2021.26.50.2101147
Loading

Data & Media loading...

Submit comment
Close
Comment moderation successfully completed
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error