Trajectories of hospitalisation for patients infected with SARS-CoV-2 variant B.1.1.7 in Norway, December 2020 - April 2021

Whittaker, R.; Brathen Kristofferson, A.; Seppala, E.; Valcarcel Salamanca, B.; Veneti, L.; Larsdatter Storm, M.; Boas, H.; Aasand, N.; Naseer, U.; Bragstad, K.; Hungnes, O.; Kvale, R.; Golestani, K.; Feruglio, S.; Vold, L.; Nygard, K.; Alnes Buanes, E.

Background The SARS-CoV-2 variant of concern (VOC) B.1.1.7 has spread worldwide and has been associated with increased risk of severe disease. Studies on patient trajectories and outcomes among hospitalised patients infected with B.1.1.7 are essential for hospital capacity planning. Methods Using linked individual-level data from national registries, we conducted a cohort study on cases of SARS-CoV-2 in Norway hospitalised between 21 December 2020 and 25 April 2021. We calculated adjusted hazard ratios using survival analysis to examine the association between B.1.1.7 and time from symptom onset to hospitalisation, and length of stay (LoS) in hospital and ICU compared to non-VOC. We calculated adjusted odds ratios using logistic regression to examine the association between B.1.1.7 and mortality (up to 30 days post discharge) compared to non-VOC. Results We included 946 B.1.1.7 patients and 157 non-VOC. The crude median time from symptom onset to hospitalisation was 8 days (IQR: 5-10) for B.1.1.7 and 8 days (IQR: 4-11) for non-VOC. The crude median LoS in hospital was 5.0 days (IQR: 2.6-10.0) for B.1.1.7 patients and 5.1 days (IQR: 2.5-9.9) for non-VOC. Fifty-four (6%) B.1.1.7 patients died, compared to 14 (9%) non-VOC. There was no difference in the unadjusted or adjusted estimates of our outcome measures for B.1.1.7 and non-VOC patients. Conclusions B.1.1.7 does not appear to influence hospitalised patient trajectories, compared to non-VOC. These findings, along with the success of ongoing vaccination programmes, are encouraging for ongoing capacity planning in the hospital sector.