Objectives With most of the Norwegian population vaccinated against COVID-19, an increasing number and proportion of COVID-19 related hospitalisations are occurring among vaccinated patients. To support patient management and capacity planning in hospitals, we estimated the length of stay (LoS) in hospital and odds of intensive care (ICU) admission and in-hospital mortality among COVID-19 patients ≥18 years who had been vaccinated with an mRNA vaccine, compared to unvaccinated patients. Methods Using national registry data, we conducted a cohort study on SARS-CoV-2 positive patients hospitalised in Norway between 1 February and 30 September 2021, with COVID-19 as the main cause of hospitalisation. We used a Cox proportional hazards model to examine the association between vaccination status and LoS. We used logistic regression to examine the association between vaccination status and ICU admission and in-hospital mortality. Results We included 2,361 patients, including 70 (3%) partially vaccinated and 183 (8%) fully vaccinated. Fully vaccinated patients 18-79 years had a shorter LoS in hospital overall (adjusted hazard ratio for discharge: 1.35, 95%CI: 1.07-1.72), and lower odds of ICU admission (adjusted odds ratio: 0.57, 95%CI: 0.33-0.96). Similar estimates were observed when collectively analysing partially and fully vaccinated patients. We observed no difference in the LoS for patients not admitted to ICU, nor odds of in-hospital death between vaccinated and unvaccinated patients. Conclusions Vaccinated patients hospitalised with COVID-19 in Norway have a shorter LoS and lower odds of ICU admission than unvaccinated patients. These findings can support patient management and ongoing capacity planning in hospitals.
Competing Interest Statement
The authors have declared no competing interest.
The authors received no specific funding for this work.
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Ethical approval for this study was granted by Regional Committees for Medical Research Ethics – South East Norway, reference number 249509. The need for informed consent was waived by the ethics committee.
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Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv