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Abstract

We included 39,524 COVID-19 Omicron and 51,481 Delta cases reported in Norway from December 2021 to January 2022. We estimated a 73% reduced risk of hospitalisation (adjusted hazard ratio: 0.27; 95% confidence interval: 0.20–0.36) for Omicron compared with Delta. Compared with unvaccinated groups, Omicron cases who had completed primary two-dose vaccination 7–179 days before diagnosis had a lower reduced risk than Delta (66% vs 93%). People vaccinated with three doses had a similar risk reduction (86% vs 88%).

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/content/10.2807/1560-7917.ES.2022.27.4.2200077
2022-01-27
2024-12-21
/content/10.2807/1560-7917.ES.2022.27.4.2200077
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References

  1. Brandal LT, MacDonald E, Veneti L, Ravlo T, Lange H, Naseer U, et al. Outbreak caused by the SARS-CoV-2 Omicron variant in Norway, November to December 2021. Euro Surveill. 2021;26(50):2101147.  https://doi.org/10.2807/1560-7917.ES.2021.26.50.2101147  PMID: 34915975 
  2. Norwegian Institute of Public Health (FHI). Ukerapport uke 2 (10.01 - 16.01.22): Ukerapporter om koronavirus og covid-19. [Weekly report week 2 (10–16 Jan 2022): Weekly reports about coronavirus and COVID-19]. Oslo: FHI; 2022. Norwegian. Available from: https://www.fhi.no/contentassets/8a971e7b0a3c4a06bdbf381ab52e6157/vedlegg/2022/ukerapport-uke-2-10.01---16.01.22.pdf
  3. Norwegian Institute of Public Health (FHI). Ukerapport uke 52 (27.12.21 - 02.01.22): Ukerapporter om koronavirus og covid-19. [Weekly report week 52 (27 Dec 2021–2 Jan 2022): Weekly reports about coronavirus and COVID-19]. Oslo: FHI; 2022. Norwegian. Available from: https://www.fhi.no/contentassets/8a971e7b0a3c4a06bdbf381ab52e6157/vedlegg/2021/ukerapport-uke-52-27.12.21---02.01.22.pdf
  4. Norwegian Institute of Public Health (FHI). Emergency preparedness register for COVID-19 (Beredt C19). Oslo: FHI; 2021. Available from: https://www.fhi.no/en/id/infectious-diseases/coronavirus/emergency-preparedness-register-for-covid-19
  5. Statens Serum Institut (SSI). Status of the SARS-CoV-2 variant Omicron in Denmark. Copenhagen: SSI; 2022. Available from: https://files.ssi.dk/covid19/omikron/statusrapport/rapport-omikronvarianten-03012022-9gj3
  6. UK Health Security Agency. SARS-CoV-2 variants of concern and variants under investigation in England. Technical briefing: Update on hospitalisation and vaccine effectiveness for Omicron VOC-21NOV-01 (B.1.1.529). London: UK Health Security Agency; 2021. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1044481/Technical-Briefing-31-Dec-2021-Omicron_severity_update.pdf
  7. Lewnard JA, Hong VX, Patel MM, Kahn R, Lipsitch M, Tartof SY. Clinical outcomes among patients infected with Omicron (B.1.1.529) SARS-CoV-2 variant in southern California. medRxiv.2022.01.11.22269045. preprint. https://doi.org/ https://doi.org/10.1101/2022.01.11.22269045  https://doi.org/10.1101/2022.01.11.22269045 
  8. Ulloa AC, Buchan SA, Daneman N, Brown KA. Early estimates of SARS-CoV-2 Omicron variant severity based on a matched cohort study, Ontario, Canada. medRxiv.2021.12.24.21268382. preprint. https://doi.org/ https://doi.org/10.1101/2021.12.24.21268382 
  9. Andrews N, Stowe J, Kirsebom F, Toffa S, Rickeard T, Gallagher E, et al. Effectiveness of COVID-19 vaccines against the Omicron (B.1.1.529) variant of concern. medRxiv.2021.12.14.21267615. preprint. https://doi.org/ https://doi.org/10.1101/2021.12.14.21267615  https://doi.org/10.1101/2021.12.14.21267615 
  10. Buchan SA, Chung H, Brown KA, Austin PC, Fell DB, Gubbay JB, et al. Effectiveness of COVID-19 vaccines against Omicron or Delta infection. medRxiv,2021.12.30.21268565. preprint. https://doi.org/ https://doi.org/10.1101/2021.12.30.21268565  https://doi.org/10.1101/2021.12.30.21268565 
  11. Lyngse FP, Hvas Mortensen L, Denwood MJ, Engbo Christiansen L, Holten Møller C, Skov RL, et al. SARS-CoV-2 Omicron VOC transmission in Danish households. medRxiv. 2021.12.27.21268278. preprint. https://doi.org/ https://doi.org/10.1101/2021.12.27.21268278  https://doi.org/10.1101/2021.12.27.21268278 
  12. Hansen CH, Blicher Schelde A, Rask Moustsen-Helm I, Emborg H-D, Grove Krause T, Mølbak K, et al. Vaccine effectiveness against SARS-CoV-2 infection with the Omicron or Delta variants following a two-dose or booster BNT162b2 or mRNA-1273 vaccination series: A Danish cohort study. medRxiv.2021.12.20.21267966. preprint. https://doi.org/ https://doi.org/10.1101/2021.12.20.21267966  https://doi.org/10.1101/2021.12.20.21267966 
  13. Garrett N, Tapley A, Andriesen J, Seocharan I, Fisher LH, Bunts L, et al. High rate of asymptomatic carriage associated with variant strain Omicron. medRxiv.2021.12.20.21268130. preprint. https://doi.org/ https://doi.org/10.1101/2021.12.20.21268130  https://doi.org/10.1101/2021.12.20.21268130 
  14. Folkehelseinstituttet (FHI). Flere med alvorlig nedsatt immunforsvar bør ta 3. dose koronavaksine. [More people with a severely impaired immune system should take a 3rd dose of corona vaccine]. Oslo: FHI; 2021. Norwegian Available from: https://www.fhi.no/nyheter/2021/flere-med-alvorlig-nedsatt-immunforsvar-bor-ta-3.-dose-koronavaksine
  15. Nishiura H, Klinkenberg D, Roberts M, Heesterbeek JA. Early epidemiological assessment of the virulence of emerging infectious diseases: a case study of an influenza pandemic. PLoS One. 2009;4(8):e6852.  https://doi.org/10.1371/journal.pone.0006852  PMID: 19718434 
Reduced risk of hospitalisation among reported COVID-19 cases infected with the SARS-CoV-2 Omicron BA.1 variant compared with the Delta variant, Norway, December 2021 to January 2022
<p class="citation"> <span>Citation style for this article:</span> <span class="meta-value authors"> <a href="/search?value1=Lamprini+Veneti&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Veneti Lamprini</a>, <a href="/search?value1=H%C3%A5kon+B%C3%B8%C3%A5s&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Bøås Håkon</a>, <a href="/search?value1=Anja+Br%C3%A5then+Kristoffersen&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Bråthen Kristoffersen Anja</a>, <a href="/search?value1=Jeanette+St%C3%A5lcrantz&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Stålcrantz Jeanette</a>, <a href="/search?value1=Karoline+Bragstad&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Bragstad Karoline</a>, <a href="/search?value1=Olav+Hungnes&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Hungnes Olav</a>, <a href="/search?value1=Margrethe+Larsdatter+Storm&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Storm Margrethe Larsdatter</a>, <a href="/search?value1=Nina+Aasand&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Aasand Nina</a>, <a href="/search?value1=Gunnar+R%C3%B8&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Rø Gunnar</a>, <a href="/search?value1=Jostein+Starrfelt&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Starrfelt Jostein</a>, <a href="/search?value1=Elina+Sepp%C3%A4l%C3%A4&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Seppälä Elina</a>, <a href="/search?value1=Reidar+Kv%C3%A5le&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Kvåle Reidar</a>, <a href="/search?value1=Line+Vold&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Vold Line</a>, <a href="/search?value1=Karin+Nyg%C3%A5rd&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Nygård Karin</a>, <a href="/search?value1=Eirik+Alnes+Buanes&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Buanes Eirik Alnes</a>, <a href="/search?value1=Robert+Whittaker&option1=author&noRedirect=true" class="nonDisambigAuthorLink">Whittaker Robert</a></span>. Reduced risk of hospitalisation among reported COVID-19 cases infected with the SARS-CoV-2 Omicron BA.1 variant compared with the Delta variant, Norway, December 2021 to January 2022. <a href="/content/ecdc">Euro Surveill.</a> 2022;27(4):pii=2200077. <a href="https://doi.org/10.2807/1560-7917.ES.2022.27.4.2200077" title="doi link" target="_blank">https://doi.org/10.2807/1560-7917.ES.2022.27.4.2200077</a> <span class="ES_Article_citation"> <span class="generated">Received</span>: 21 Jan 2022;&nbsp;&nbsp; <span class="generated">Accepted</span>: 25 Jan 2022 </span> </p>
/content/10.2807/1560-7917.ES.2022.27.4.2200077
/content/10.2807/1560-7917.ES.2022.27.4.2200077
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