key: cord-0842774-i5fb5s37
authors: Whittaker, Robert; Kristofferson, Anja Bråthen; Seppälä, Elina; Salamanca, Beatriz Valcarcel; Veneti, Lamprini; Storm, Margrethe Larsdatter; Bøås, Håkon; Aasand, Nina; Naseer, Umaer; Bragstad, Karoline; Kvåle, Reidar; Golestani, Karan; Feruglio, Siri; Vold, Line; Nygård, Karin; Buanes, Eirik Alnes
title: Trajectories of hospitalisation for patients infected with SARS-CoV-2 variant B.1.1.7 in Norway, December 2020 – April 2021
date: 2021-07-28
journal: J Infect
DOI: 10.1016/j.jinf.2021.07.025
sha: 7fa5e8219386f4f6c4ea0154f234d2d3ce6b7d7e
doc_id: 842774
cord_uid: i5fb5s37

nan

emergence of variants of concern (VOC) remains an area of substantial concern as we continue to battle the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This includes lineage B.1.1.7 (alpha variant), first detected in south-east England in September 2020 (1) . In Norway (2), as well as other European countries (3, 4) . Evidence on differences in patient trajectories and outcomes among hospitalised patients infected with B.1.1.7 compared to other lineages is thus essential to support ongoing capacity planning in the health system.

In this journal, a study from Garvey and colleagues analysed a cohort of 152 patients from the UK's largest hospital trust infected with the VOC B.1.1.7 (and one B.1.351) compared to other variants (5) .

They reported no statistically significant difference in the mean length of stay (LoS) in hospital or ICU, proportion of patients admitted to ICU, nor proportion of patients who died (5) . In Norway we have conducted a similar study on a representative cohort of 1,103 SARS-CoV-2 positive patients using linked, patient-level data from national registries.

A full description of the data sources and methods is available here (6) . Briefly, the data come from the national emergency preparedness registry, which comprises data from a variety of central health registries, national clinical registries and other national administrative registries. We included notified cases of COVID-19 who were hospitalised not more than two days before and less than 28 days after a positive SARS-CoV-2 test in Norway between 21 December 2020 and 25 April 2021, who had available variant data after whole genome sequencing (WGS) or PCR screening, and who had not been vaccinated with a COVID-19 vaccine before sampling or hospitalisation. We extracted and linked data on 2 June 2021, ensuring a minimum of 36 days follow-up since last date of hospitalisation. Although elective surgeries in some regions were postponed during a surge in hospitalisations among COVID-19 cases in mid-March, hospitals in Norway functioned within capacity during the study period, while there were no major changes in treatment guidelines for SARS-CoV-2 patients in hospital or ICU. Variants were identified based on WGS using Illumina or Nanopore technology, partial sequencing by Sanger sequencing or PCR screening for selected targets. Of 2,354 unvaccinated patients in the study period, 1186 (50%) had known virus variant, and few differences were observed between patients who had known virus variant and those who did not (6) . We used survival analysis (Kaplan Meier curves, adjusting for right censuring) to examine the association between B.1.1.7 and time from symptom onset to hospitalisation, and LoS in hospital and in ICU, compared to non-VOC. We used logistic regression to examine the association between B.1. 

First and foremost, we wish to thank all those who have helped report data to the national emergency preparedness registry at the Norwegian Institute of Public Health (NIPH) throughout the pandemic. We also highly acknowledge the efforts that regional laboratories have put into establishing a routine variant screening procedure or whole genome sequencing at short notice and registration of all analysis in national registries for surveillance. Thanks also to the staff at the Virology and Bacteriology departments at NIPH involved in national variant identification and whole genome analysis of SARS-CoV-2 viruses. We also highly acknowledge the efforts of staff at hospitals around Norway to ensure the reporting of timely and complete data to the Norwegian Intensive Care and Pandemic Registry, as well as colleagues at the register itself. We would also like to thank Anja Elsrud Schou Lindman, project director for the national preparedness registry, and all those who have enabled data transfer to this registry, especially Gutorm Høgåsen at the NIPH, who has been in charge of the establishment and administration of the registry. We would like to acknowledge Jacob Berild and Camilla Mauroy, who coordinate the surveillance of COVID-19 related deaths at the NIPH.

We would like to thank Trude Marie Lyngstad, Anders Skyrud Danielsen, Nora Dotterud and Evy Dvergsdal at the NIPH for their assistance in cleaning the data from different registries. 6 The authors declare that they have no competing interests.

The authors received no specific funding for this work.

Ethical approval for this study was granted by Regional Committees for Medical Research Ethics -South East Norway, reference number 249509.

The datasets analysed during the current study come from the national emergency preparedness registry for COVID-19, housed at the Norwegian Institute of Public Health. The preparedness registry is temporary and comprises data from a variety of central health registries, national clinical registries and other national administrative registries. Further information on the preparedness registry, including access to data from each individual data source, is available at https://www.fhi.no/en/id/infectious-diseases/coronavirus/emergency-preparedness-register-forcovid-19/. VOC: Variant of concern; ICU: Intensive care unit; IQR: Interquartile range; 95%CI: 95% confidence interval.

Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England

Increased Risk of Hospitalisation and Intensive Care Admission Associated With Infection With SARS-CoV-2 Variants B.1.1.7 and B.1.351 in Norway

Risk of hospitalisation associated with infection with SARS-CoV-2 lineage B.1.1.7 in Denmark: an observational cohort study

Characteristics of SARS-CoV-2 variants of concern B.1.1.7, B.1.351 or P.1: data from seven EU/EEA countries, weeks 38/2020 to 10/2021

Observations of SARS-CoV-2 variant of concern B.1.1.7 at the UK's largest hospital Trust

Trajectories of hospitalisation for patients infected with SARS-CoV-2 variant B

Genomic characteristics and clinical effect of the emergent SARS-CoV-2 B.1.1.7 lineage in London, UK: a wholegenome sequencing and hospital-based cohort study

Effect of the new SARS-CoV-2 variant B.1.1.7 on children and young people

Mortality and critical care unit admission associated with the SARS-CoV-2 lineage B.1.1.7 in England: an observational cohort study

Adjusted for age (continuous variable either linearly or with a spline), sex, county of residence, regional health authority, week of admission, country of birth (Norway, overseas and unknown), main cause of hospitalisation (COVID-19, other, unknown) and underlying risk factors. The variables included in the final multivariable model were obtained by forward model selection

^^ age (continuous variable either linearly or with a spline), sex, county of residence, regional health authority, week of admi ssion, country of birth (Norway, overseas and unknown), main cause of hospitalisation (COVID-19, other, unknown), underlying risk factors and admission to ICU. The variables included in the final multivariable model were obtained by forward model selection

Number of patients with known date of symptom onset: non-VOC 93/157 (60%)

Excludes eight B.1.1.7 patients who were still admitted to ICU at the end of the study period, and five non-VOC and 26 B.1.1.7 who passed away in ICU

Death in-hospital or up to 30 days post discharge is limited to patients who had been discharged by

7), in order to ensure at least 30 days of follow-up post discharge for all patients