ABSTRACT
ObjectivesTo estimate the risk of hospitalisation among reported cases of the Delta-variant of SARS-CoV-2 compared to the Alpha variant in Norway. We also estimated the risk of hospitalisation by vaccination status. MethodsWe conducted a cohort study on laboratory-confirmed cases of SARS-CoV-2 in Norway, diagnosed between 3 May and 15 August 2021. We calculated adjusted risk ratios (aRR) with 95% confidence intervals (CIs) using multivariable binomial regression, accounting for variant, vaccination status, demographic characteristics, week of sampling and underlying comorbidities. ResultsWe included 7,977 cases of Delta and 12,078 cases of Alpha. Overall, 347 (1.7%) cases were hospitalised. The aRR of hospitalisation for Delta compared to Alpha was 0.97 (95%CI 0.76-1.23). Partially vaccinated cases had a 72% reduced risk of hospitalisation (95%CI 59%-82%), and fully vaccinated cases had a 76% reduced risk (95%CI 61%-85%), compared to unvaccinated cases. ConclusionsWe found no difference in the risk of hospitalisation for Delta cases compared to Alpha cases in Norway. Further research from a wide variety of settings is needed to better understand the association between the Delta variant and severe disease. Our results support the notion that partially and fully vaccinated persons are highly protected against hospitalisation with COVID-19. HighlightsO_LIThe SARS-CoV-2 Delta variant has dominated in Norway since July 2021 C_LIO_LIThere was no difference in the risk of hospitalisation for Delta cases compared to Alpha C_LIO_LIPartially and fully vaccinated cases had >70% decreased risk of hospitalisation C_LI
ABSTRACT
BackgroundThe 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. MethodsUsing 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 an intensive care unit 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. ResultsWe 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. ConclusionsB.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.
ABSTRACT
AimTo study whether employees in occupations that typically imply close contact with other people are tested more and at higher risk of confirmed SARS-CoV-2 infection (COVID-19) and related hospitalization, in the 1st and 2nd wave of infection in Norway. MethodsIn all 3 559 694 residents of Norway on January 1st 2020 aged 20-70 (with mean [SD] age 44.1 [14.3] years and 51% men), we studied COVID-19 testing patterns sorted by occupation (using Standard Classification of Occupations [ISCO-08]). We also studied whether selected occupations had a higher risk of 1) confirmed COVID-19 and 2) hospitalization with COVID-19, compared to everyone else aged 20-70 years using logistic regression adjusted for age, sex, testing behavior, and own and maternal country of birth. ResultsOccupations with high frequency of testing (e.g. health personnel and teachers) had a low frequency of positive tests. Nurses, physicians, dentists, physiotherapists, bus/tram and taxi drivers had 1.1-4 times the odds of COVID-19 during the 1st wave, whereas bartenders, waiters, transport conductors and travel stewards had 1.1-3 times the odds of COVID-19 during the 2nd wave (when compared to everyone else). Teachers had moderately increased odds of COVID-19. Occupation may be of limited relevance for hospitalization with the disease. ConclusionStudying the entire Norwegian population using international standardized codes of occupations, our findings may be of relevance to national and regional authorities in handling the pandemic. Also, our findings provide a knowledge foundation for the more targeted future studies of lockdown, testing strategies and disease control measures.
