SARS-CoV-2 and risk of psychiatric hospital admission and use of psychopharmaceuticals: A nationwide registry study of 4,585,083 adult Danish citizens.

BACKGROUND: Current evidence on the risk of admission- or medication-requiring psychiatric sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is limited to selected populations, short durations, and loss to follow-up. This study examined if SARS-CoV-2 infection was associated with increased long-term risk of psychiatric admissions and de novo prescription of psychoactive medication in the general population of Denmark. METHODS: Adults (≥18 years) were assigned to either the control or SARS-CoV-2 group based on polymerase chain reaction (PCR) tests between 1 January 2020 and 27 November 2021. Infected subjects were matched 1:5 to control subjects by propensity score. Incidence rate ratios (IRRs) were calculated. Adjusted Cox regression was applied to the unmatched population with SARS-CoV-2 infection as a time-dependent covariate. Follow-up time was 12 months or until the end of the study. RESULTS: A total of 4,585,083 adults were included in the study. Approximately 342,084 had a PCR-confirmed SARS-CoV-2 infection and were matched 1:5 with 1,697,680 controls. The IRR for psychiatric admission was 0.79 in the matched population (95% confidence interval [CI]: 0.73-0.85, p < 0.001). In the unmatched population, the adjusted hazard ratios (aHR) for psychiatric admission were either below 1.00 or with a 95% CI lower limit of 1.01. SARS-CoV-2 infection was associated with an increased risk of de novo prescription of psychoactive medication in both the matched (IRR 1.06, 95% CI: 1.02-1.11, p < 0.01) and unmatched population (HR 1.31, 95% CI: 1.28-1.34, p < 0.001). CONCLUSIONS: We found a signal of increased use of psychoactive medication, specifically benzodiazepines, among SARS-CoV-2-positive persons, but the risk of psychiatric admissions did not increase.

Factors influencing the immune response over 15 months after SARS-CoV-2 infection: A longitudinal population-wide study in the Faroe Islands.

BACKGROUND: The durability of SARS-CoV-2 antibody response and the resulting immunity to COVID-19 is unclear. OBJECTIVES: To investigate long-term humoral immunity to SARS-CoV-2. METHODS: In this nationwide, longitudinal study, we determined antibody response in 411 patients aged 0-93 years from two waves of infections (March to December 2020) contributing 1063 blood samples. Each individual had blood drawn on 4-5 occasions 1-15 months after disease onset. We measured total anti-SARS-CoV-2 receptor-binding domain (RBD) antibody using a qualitative RBD sandwich ELISA, IgM, IgG and IgA levels using an quantitative in-house ELISA-based assay  and neutralizing antibodies (NAbs) using an in-house ELISA-based pseudoneutralizing assay. IgG subclasses were analyzed in a subset of samples by ELISA-based assay. We used nonlinear models to study the durability of SARS-CoV-2 antibody responses and its influence over time. RESULTS: After 15 months, 94% still had detectable circulating antibodies, mainly the IgG isotype, and 92% had detectable NAbs. The distribution of IgG antibodies varied significantly over time, characterized by a biphasic pattern with an initial decline followed by a plateau after approximately 7 months. However, the NAbs remained relatively stable throughout the period. The strength of the antibody response was influenced by smoking and hospitalization, with lower IgG levels in smokers and higher levels in hospitalized individuals. Antibody stability over time was mainly associated with male sex and older age with higher initial levels but more marked decrease. CONCLUSIONS: The humoral immune response to SARS-CoV-2 infection varies depending on behavioral factors and disease severity, and antibody stability over 15 months was associated with sex and age.

Effects of the COVID-19-induced lockdown period on general well-being, perceived stress and activity levels in the Faroe Islands.

AIMS: Detrimental effects on health and well-being were reported during the COVID-19-induced lockdown periods in several countries, but these associations have not been studied in small-scale island societies. This study aimed to examine the lockdown period's impact on general well-being, perceived stress and activity levels in the Faroe Islands. METHODS: We used cross-sectional data from two extensive population-based surveys of the general health conducted in November 2019 (the pre-COVID survey; n=2906), and four to six weeks into the first national lockdown (the lockdown survey; n=1204). RESULTS: A larger proportion of participants in the lockdown survey versus pre-COVID survey displayed excellent/very good self-rated health (68.1% vs. 62.0%; p<0.001), and the same pattern was observed for reporting good quality of life (85.7% vs. 82.7%; p<0.05). These associations remained statistically significant in a logistic regression model after adjusting for characteristics for which varying impact of the pandemic has been shown. Indicators of health behaviour showed that larger proportions of participants kept active during the lockdown survey versus pre-COVID survey, and these differences were statistically significant for physical, mental and spiritual activities (p<0.001). On the other hand, similar stress levels in the pre-COVID/lockdown periods were observed, but stratified analysis showed that participants with a high-stress level displayed better self-rated health in the lockdown period compared to the pre-COVID period (p=0.001). CONCLUSIONS: Findings indicate that self-reported health and quality of life improved during the early phase of the COVID lockdown, and individuals reported higher activity levels associated with good mental health during the COVID-19-induced lockdown period.

Findings in Danish long-term care facilities in the first year of the SARS-CoV-2 pandemic.

PURPOSE: To describe the occurrence of SARS-CoV-2 infections, deaths and outbreaks among residents in Danish long-term care facilities (LTCFs) from February 2020 to February 2021. METHODS: Danish COVID-19 national register data from a newly implemented automated surveillance system was used to describe incidence rate and deaths (per 1000 residents' years), number of tests, SARS-CoV-2 infections and outbreaks among LTCF residents. A case was defined as a LTCF resident with a positive SARS-CoV-2 PCR test. An outbreak was defined as two or more cases in one LTCF within a 14-day period, and considered closed if no new cases had occurred within 28 days. Death was defined as occurring within 30-days of a positive test. RESULTS: A total of 55,359 residents living in 948 LTCFs were included. The median age of the residents was 85 years and 63% were female. There was a total of 3712 cases found among residents across 43% of all LTCFs. Nearly all (94%) cases were linked to outbreaks. Higher numbers of cases and outbreaks were seen in Denmark's Capital Region compared to other regions. Overall, 22 SARS-CoV-2 deaths and 359 deaths (non-SARS-CoV-2) per 1000 resident years were identified in the study period. CONCLUSION: Less than half of LTCFs identified any cases. The majority of cases were linked to outbreaks, emphasizing the importance of preventing introductions of SARS-CoV-2 into the facilities. Furthermore, it highlights the need to invest efforts into infrastructures, routine procedures and monitoring of SARS-CoV-2 in LTCFs to limit the introduction and the spread of SARS-CoV-2.

Experience with sotrovimab treatment of SARS-CoV-2-infected patients in Denmark.

AIMS: To evaluate the experience with use of sotrovimab following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in high-risk groups. METHODS: In a nationwide, population-based cohort study, we identified all individuals treated with sotrovimab (N = 2933) and stratified them by 4 high-risk groups: (A) malignant haematological disease, (B) solid organ transplantation, (C) anti-CD20 therapy ≤1 year and (D) other risks. Cox regression analysis was used to calculate hazard ratios for hospitalization, death and associated prognostic factors. RESULTS: Of 2933 sotrovimab-treated individuals, 83% belonged to high-risk groups (37.6% haematological malignancy, 27.4% solid organ transplantation and 17.5% treatment with anti-CD20 ≤1 year). Only 17.8% had other risks (11.8% were pregnant, 10.7% primary immunodeficiency, 21.2% other malignancy, 4.3% received anti-CD20 >1 year and 52.0% other/unknown causes). Within 90 days of infusion, 30.2% were hospitalized and 5.3% died. The main prognostic factors were the predefined high-risk groups, mainly malignant haematological disease and age ≥65 years. Number of COVID-19 vaccines (≥3) was associated with a decreased risk of hospitalization. The Delta but not the Omicron BA.2 variant was associated with a higher risk of death compared to the BA.1 variant. CONCLUSION: More than 90% of the patients treated with sotrovimab belonged to the very high-risk groups as described in the Danish guidelines. Sotrovimab-treated individuals remained at a high risk of hospitalization and death which was strongly associated with the underlying immunocompromised state and age. Having received >3 COVID-19 vaccines was association with decreased risk of death and hospitalization.

Prayer and meditation practices in the early COVID-19 pandemic: A nationwide survey among Danish pregnant women. The COVIDPregDK study.

BACKGROUND: The emergence of the COVID-19 pandemic and the derived changes in maternity care have created stress and anxiety among pregnant women in different parts of the world. In times of stress and crisis, spirituality, including spiritual and religious practices, may increase. OBJECTIVE: To describe if the COVID-19 pandemic influenced pregnant women's considerations and practises of existential meaning-making and to investigate such considerations and practices during the early pandemic in a large nationwide sample. METHODS: We used survey data from a nationwide cross-sectional study sent to all registered pregnant women in Denmark during April and May 2020. We used questions from four core items on prayer and meditation practices. RESULTS: A total of 30,995 women were invited, of whom 16,380 participated (53%). Among respondents, we found that 44% considered themselves believers, 29% confirmed a specific form of prayer, and 18% confirmed a specific form of meditation. In addition, most respondents (88%) reported that the COVID-19 pandemic had not influenced their responses. CONCLUSION: In a nationwide Danish cohort of pregnant women, existential meaning-making considerations and practices were not changed due to the COVID-19 pandemic. Nearly one in two study participants described themselves as believers, and many practised prayer and/or meditation.

Are changes in physical activity during COVID-19 associated with mental health among Danish university students?

Aims: The benefits associated with being physical active on mental health is well-established, but little is known on how rapid changes in physical activity are associated with mental health. This study investigated the association between changes in physical activity and mental health among Danish university students during the first COVID-19 lockdown. Methods: Online survey data were collected among 2,280 university students at the University of Southern Denmark and University of Copenhagen in May-June 2020 as part the "COVID-19 International Student Well-being Study." Multiple linear regressions were used to analyze associations between changes in physical activity and mental health (depression and stress scores) adjusted for potential socio-economic confounders. Results: During the first COVID-19 lockdown, 40% decreased their moderate and 44% their vigorous physical activity, while 16% increased their moderate and 13% their vigorous physical activity. Overall, students with a stable physical activity level had the lowest mean depressive and stress scores. Adjusted analyses showed that a decrease in vigorous and moderate physical activity level was significantly associated with a higher depression score (mean difference (vigorous): 1.36, p < 0.001 and mean difference (moderate): 1.55, p < 0.001). A decrease in vigorous physical activity and an increase in moderate physical activity was associated with a 1-point increase in the PSS-4 stress score (p < 0.001). Conclusion: A substantial proportion of students changed their physical activity level during lockdown. Our findings emphasize the importance of staying physically active during COVID-19 lockdown. This knowledge might be important for relevant health authorities to bridle post-pandemic mental health challenges.

Nationwide Utilization of Danish Government Electronic letter system for increasing inFLUenza vaccine uptake (NUDGE-FLU): Study protocol for a nationwide randomized implementation trial.

BACKGROUND: Annual influenza vaccination is widely recommended in older adults and other high-risk groups including patients with cardiovascular disease. The real-world effectiveness of influenza vaccination is limited by suboptimal uptake and effective strategies for increasing vaccination rates are therefore needed. The purpose of this trial is to investigate whether behavioral nudges digitally delivered via the Danish nationwide mandatory governmental electronic letter system can increase influenza vaccination uptake among older adults. METHODS: The NUDGE-FLU trial is a randomized implementation trial randomizing all Danish citizens aged 65 years and above without an exemption from the Danish mandatory governmental electronic letter system to receive no digitally delivered behavioral nudge (usual care arm) or to receive one of 9 electronic letters (intervention arms) each leveraging different behavioral science strategies. The trial has randomized 964,870 participants with randomization clustered at the household level (n = 691,820 households). Intervention letters were delivered on September 16, 2022, and follow-up is currently ongoing. All trial data are captured using the nationwide Danish administrative health registries. The primary end point is the receipt of an influenza vaccine on or before January 1, 2023. The secondary end point is time to vaccination. Exploratory end points include clinical events such as hospitalization for influenza or pneumonia, cardiovascular events, all-cause hospitalization, and all-cause mortality. DISCUSSION: The nationwide randomized NUDGE-FLU trial is one of the largest implementation trials ever conducted and will provide important insights into effective communication strategies to maximize vaccination uptake among high-risk groups. TRIAL REGISTRATION: Clinicaltrials.gov: NCT05542004, registered September 15, 2022, https://clinicaltrials.gov/ct2/show/NCT05542004.

Risk of Type 1 Diabetes in Children Is Not Increased After SARS-CoV-2 Infection: A Nationwide Prospective Study in Denmark.

OBJECTIVE: It has been hypothesized that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children can increase risk of developing type 1 diabetes. RESEARCH DESIGN AND METHODS: We undertook a prospective, register-based analysis of children in Denmark by investigating the association between SARS-CoV-2 infection and subsequent risk of type 1 diabetes. During the pandemic, Denmark had one of the highest test rates per capita in the world, and 90% of all Danish children were tested. RESULTS: Compared with children with a history of only negative SARS-CoV-2 tests, we did not observe a higher risk of first-time diagnosis of type 1 diabetes in children 30 days or more after a positive SARS-CoV-2 test (hazard ratio 0.85; 95% CI 0.70-1.04). CONCLUSIONS: Our data do not support that SARS-CoV-2 infection is associated with type 1 diabetes or that type 1 diabetes should be a special focus after a SARS-CoV-2 infection in children.

The COVID-19 pandemic and the timing of government response: A comparison of four Nordic countries March-June 2020.

OBJECTIVES: The aim is to compare Sweden, Denmark, Finland and Norway regarding government response to the COVID-19 pandemic in mid-March-June 2020 using the Oxford Government Response Tracker. STUDY DESIGN: Descriptive longitudinal ecological study. METHODS: Descriptive analysis of time series data. RESULTS: Sweden displayed a far lower response index in March. By late April indexes were similar. In May-June, response indexes were lower in Finland and Norway than in Sweden. The average response index in mid-March-June was similar in Sweden, Finland and Norway. CONCLUSIONS: The government response in the four countries indicates that timing of response was essential. Sweden's slow and weak initial government response in March-April was followed by less loosening of government response in May-June compared with, especially, Finland and Norway, which resulted in similar average government response in mid-March-June for the three countries. As a comparison, COVID-19 mortality per capita was 10 times higher in Sweden than in Finland and Norway, and five times higher than in Denmark during the same period.

First molecular documented case of a rarely reported parasite: Plasmodium knowlesi infection in Denmark in a traveller returning from Malaysian Borneo.

Plasmodium knowlesi has been reported as an emerging infection throughout the Southeast Asian region, especially in the Malaysian state of Sabah, where it accounts for the majority of the malaria cases reported. This is in contrast to Europe, where imported P. knowlesi is a rarely reported infection. We present a case of P. knowlesi infection in a Danish woman returning from a short trip to Malaysian Borneo. Microscopy of blood smears revealed 0.8% infected erythrocytes, but due to the atypical morphological presentation, a conclusive species identification was made by molecular methods. Plasmodium knowlesi is a potentially fatal infection and taking the increasing travel activity into consideration after the coronavirus disease 2019 (COVID-19) pandemic, P. knowlesi should be a differential diagnosis in patients with travel-associated illness returning from highly endemic Southeast Asian areas.

The impact of the COVID-19 lockdown on birthweight among singleton term birth in Denmark.

In Denmark, a nationwide COVID-19 lockdown was implemented on March 12, 2020 and eased on April 14, 2020. The COVID-19 lockdown featured reduced prevalence of extremely preterm or extremely low birthweight births. This study aims to explore the impact of this COVID-19 lockdown on term birthweights in Denmark. We conducted a nationwide register-based cohort study on 27,870 live singleton infants, born at term (weeks 37-41), between March 12 and April 14, 2015-2020, using data from the Danish Neonatal Screening Biobank. Primary outcomes, corrected for confounders, were birthweight, small-for-gestational-age (SGA), and large-for-gestational-age (LGA), comparing the COVID-19 lockdown to the previous five years. Data were analysed using linear regression to assess associations with birthweight. Multinomial logistic regression was used to assess associations with relative-size-for-gestational-age (xGA) categories. Adjusted mean birthweight was significantly increased by 16.9 g (95% CI = 4.1-31.3) during the lockdown period. A dip in mean birthweight was found in gestational weeks 37 and 38 balanced by an increase in weeks 40 and 41. The 2020 lockdown period was associated with an increased LGA prevalence (aOR 1.13, 95% CI = 1.05-1.21). No significant changes in proportions of xGA groups were found between 2015 and 2019. The nationwide COVID-19 lockdown resulted in a small but significant increase in birthweight and proportion of LGA infants, driven by an increase in birthweight in gestational weeks 40 and 41.

The COVID-19 pandemic has not affected the mortality for patients admitted with pneumonia in Denmark.

During the COVID-19 pandemic, several hospital systems observed a reduction in patients with respiratory complaints. Using the Danish national registers, we conducted an observational study on disease severity and 30-day all-cause mortality for acutely admitted pneumonia patients before (3/19-3/20) and during (3/20-2/21) the pandemic. We calculated mortality rate ratios and Cox regression analyses. We identified 54,405 patients and during the pandemic, patients were older, more likely to be male, had more co-morbidity and a lower albumin on admission. Crude mortality was higher during the pandemic (8.4 vs. 6.9%). Adjusted hazard ratio for 30-day all-cause mortality was 1.07 (95%CI 1.01-1.14). We showed a small but significant, increase in mortality risk for patients admitted to hospital during the COVID-19 pandemic in Denmark.

Association Between Diabetes and Mortality Among Adult Patients Hospitalized With COVID-19: A Cohort Study of Hospitalized Adults in Ontario, Canada, and Copenhagen, Denmark.

OBJECTIVES: Diabetes has been reported to be associated with an increased risk of death among patients with COVID-19. However, the available studies lack detail on COVID-19 illness severity and measurement of relevant comorbidities. METHODS: We conducted a multicentre, retrospective cohort study of patients 18 years of age and older who were hospitalized with COVID-19 between January 1, 2020, and November 30, 2020, in Ontario, Canada, and Copenhagen, Denmark. Chart abstraction emphasizing comorbidities and disease severity was performed by trained research personnel. The association between diabetes and death was measured using Poisson regression. The main outcome measure was in-hospital 30-day risk of death. RESULTS: Our study included 1,133 hospitalized patients with COVID-19 in Ontario and 305 in Denmark, of whom 405 and 75 patients, respectively, had pre-existing diabetes. In both Ontario and Denmark, patients with diabetes were more likely to be older; have chronic kidney disease, cardiovascular disease, and higher troponin levels; and be receiving antibiotics, when compared with adults without diabetes. In Ontario, 24% (n=96) of adults with diabetes died compared with 15% (n=109) of adults without diabetes. In Denmark, 16% (n=12) of adults with diabetes died in hospital compared with 13% (n=29) of those without diabetes. In Ontario, the crude mortality ratio among patients with diabetes was 1.60 (95% confidence interval [CI], 1.24 to 2.07) and in the adjusted regression model it was 1.19 (95% CI, 0.86 to 1.66). In Denmark, the crude mortality ratio among patients with diabetes was 1.27 (95% CI, 0.68 to 2.36) and in the adjusted model it was 0.87 (95% CI, 0.49 to 1.54). Meta-analysis of the 2 rate ratios from each region resulted in a crude mortality ratio of 1.55 (95% CI, 1.22 to 1.96) and an adjusted mortality ratio of 1.11 (95% CI, 0.84 to 1.47). CONCLUSION: The presence of diabetes was not strongly associated with in-hospital COVID-19 mortality independent of illness severity and other comorbidities.

COVID-19 vaccine willingness amongst patients with mental illness compared with the general population.

Patients with mental illness are at an increased risk of COVID-19 infection, morbidity, and mortality, and prioritisation of this group for COVID-19 vaccination programmes has therefore been suggested. Vaccine uptake may, however, be compromised by vaccine hesitancy amongst patients with mental illness, posing a critical public health issue. We conducted two surveys to provide weighted estimates of vaccine willingness amongst patients with mental illness and the general population of Denmark. Vaccine willingness was high in both groups, but slightly lower amongst patients with mental illness (84.8%), compared with the general population (89.5%) (p < .001). Based on these findings, vaccine hesitancy does not appear to be a major barrier for vaccine uptake amongst patients with mental illness in Denmark, but may be so in other countries with lower general vaccine willingness. Replication of the present study in other countries is strongly warranted.

Sociodemographic differences in Covid-19 vaccine uptake in Denmark: a nationwide register-based cohort study.

BACKGROUND: Covid-19 vaccination is the main strategy to reduce SARS-CoV-2 transmission, mortality and morbidity. This study aimed to examine sociodemographic differences in Covid-19 vaccine uptake among all individuals invited for Covid-19 vaccination in Denmark. METHODS: This study was designed as a nationwide register-based cohort study. The study population included all Danish residents aged 12 years or above in Denmark between December 27, 2020 and October 20, 2021. Individuals who died during the study period before receiving an invitation for Covid-19 vaccination were excluded. Associations between sociodemographic factors and Covid-19 vaccination uptake were analyzed using logistic regression models adjusting for age, sex, immigration status, educational level, disposable income and history of SARS-CoV-2 infection. RESULTS: The study population included 5,164,558 individuals. The overall vaccination coverage was 87.1% by October 20, 2021. In the full adjusted logistic regression models, the highest ORs for non-vaccination were observed among individuals aged 12-24 years (OR: 8.99 (95% CI: 8.76-9.23)), descendants of non-western immigrants (OR: 5.26 (95% CI: 5.18-5.33)), individuals who never had a PCR-test performed (OR: 2.93 (95% CI: 2.90-2.96)), individuals with primary school as highest completed educational level (OR: 2.87 (95% CI: 2.83-2.91)) and individuals with disposable income < 33,605 EUR (OR: 3.72 (95% CI: 3.52-3.93)). CONCLUSION: Overall, the Covid-19 vaccine uptake was high in Denmark. However, large sociodemographic differences in the vaccine uptake exist. The youngest age groups had the lowest vaccination coverage. Furthermore, the impact of the sociodemographic factors was more pronounced in the youngest age groups. The identified determinants may be used to design policies to help maximize the vaccination coverage.

Why trust? A mixed-method investigation of the origins and meaning of trust during the COVID-19 lockdown in Denmark.

Trust is highlighted as central to effective disease management. During the COVID-19 pandemic, Denmark seemed to embody this understanding. Characterizing the Danish response were high levels of public compliance with government regulations and restrictions coupled with high trust in the government and other members of society. In this article, we first revisit prior claims about the importance of trust in securing compliant citizen behaviour based on a weekly time-use survey that we conducted during the first weeks of the COVID-19 pandemic (2 April-18 May 2020). Analysis of activity episodes, rather than merely self-reported compliance, both reconfirms the importance of institutional trust and nuances prior suggestions of detrimental effects of trust in other citizens. These survey-based results are further augmented through thematic analysis of 21 in-depth interviews with respondents sampled from the survey participants. The qualitative analysis reveals two themes, the first focusing on trust in others in Danish society and the second on the history of trust in Denmark. Both themes are based on narratives layered in cultural, institutional and inter-personal levels and further underline that institutional and social trust are complementary and not countervailing. We conclude by discussing how our analysis suggests pathways towards an increased social contract between governments, institutions and individuals that might be of use during future global emergencies and to the overall functioning of democracies.

Severe COVID-19 during pregnancy in Sweden, Norway, and Denmark.

INTRODUCTION: Pregnancy is a risk factor for severe coronavirus disease 2019 (COVID-19) and adverse pregnancy outcomes. We aimed to explore maternal characteristics, pregnancy outcomes, vaccination status, and virus variants among pregnant women admitted to intensive care units (ICU) with severe COVID-19. MATERIAL AND METHODS: We identified pregnant women admitted to ICU in Sweden (n = 96), Norway (n = 31), and Denmark (n = 16) because of severe COVID-19, from national registers and clinical databases between March 2020 and February 2022 (Denmark), August 2022 (Sweden), or December 2022 (Norway). Their background characteristics, pregnancy outcome, and vaccination status were compared with all birthing women and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test-positive pregnant women during the same time period. We calculated the number admitted to ICU per 10 000 birthing and per 1000 SARS-CoV-2 test-positive women during the Index, Alpha, Delta, and Omicron periods. RESULTS: Women admitted to ICU had a higher mean body mass index, were more often of non-Scandinavian origin, had on average lower education and income levels, had a higher proportion of chronic and pregnancy-related conditions, delivered preterm, had neonates with low Apgar scores, and had more infants admitted to neonatal care, compared with all birthing and test-positive pregnant women. Of those admitted to ICU, only 7% had been vaccinated before admission. Overall, the highest proportion of women admitted to ICU per birthing was during the Delta period (4.1 per 10 000 birthing women). In Norway, the highest proportion admitted to ICU per test-positive pregnant women was during the Delta period (17.8 per 1000 test-positive), whereas the highest proportion of admitted per test-positive in Sweden and Denmark was seen during the Index period (15.4 and 8.9 per 1000 test-positive, respectively). CONCLUSIONS: Admission to ICU because of COVID-19 in pregnancy was a rare event in the Scandinavian countries, but women who were unvaccinated, of non-Scandinavian origin, and with lower socio-economic status were at higher risk of admission to ICU. In addition, women admitted to ICU for COVID-19 had higher risk of adverse pregnancy outcomes.