Lone Graff Stensballe

Background: Respiratory syncytial virus (RSV) is a major cause of hospitalisation among young infants worldwide. Denmark implemented a national maternal RSV vaccination programme in October 2025. In this nationwide register-based cohort study we estimate the vaccine effectiveness against RSV hospitalisation among infants aged 0-6 months following the first maternal RSV vaccination programme and evaluate the population-level impact.Methods; We included all live births between November 1, 2025 to March 31, 2026 and compared rates of RSV-related hospitalisation occurring before May 1, 2026 among infants to vaccinated and unvaccinated mothers using Cox regression with calendar time as the underlying timescale adjusted for potential confounders. Population-level impact was estimated using Danish RSV surveillance data.Findings: Of the 22,593 infants included, 16,416 (72.7%) were born to vaccinated mothers. During the study, 66 and 104 infants were hospitalised for RSV in the vaccinated and unvaccinated group, respectively. The adjusted vaccine effectiveness against RSV hospitalisation was 77.9% (95% CI 69.5-84.0) overall, higher among infants aged 0-90 days (82.6%, 95% CI 74.9-88.0) than among infants aged 91-180 days (56.8%, 95% CI 18.4-77.2). The population impact analysis showed a 70.4% reduction in RSV hospitalisations among infants aged 0-90 days.Interpretation: Maternal RSV vaccination provided substantial protection against RSV hospitalisation, particularly during the first months of life. A considerable reduction in RSV hospitalisations was observed at the population level. These findings support national programmes as an effective strategy to reduce severe RSV burden in early infancy and highlight the importance of successful programme implementation and high maternal vaccination coverage for maximising population-level benefit.

Background: Psoriasis is a chronic inflammatory skin condition. It is being increasingly treated with biologic agents targeting specific immune pathways. These treatments target specific immune system pathways involved in the disease. Drug survival (how long patients remain on a given treatment) is a key measure of long-term effectiveness and safety. Objectives: To analyse the drug survival rates of approved biologics for psoriasis using Danish nationwide register-based data from 2018 to 2023. Methods: This study used a nationwide register-based cohort of patients diagnosed with psoriasis in Denmark who were treated with biologics between 2018 and 2023. Patients were stratified by the presence or absence of psoriatic arthritis (PsA). Drug survival was assessed using Kaplan–Meier curves, and the rate of discontinuation was analysed using Cox proportional hazards regression models. Results: Of the biologics studied, infliximab had the highest 1-year drug survival (49%), followed by ustekinumab (42%). Bimekizumab, the most recently introduced biologic in Denmark, had a 19% drug survival rate after 349 days. Ustekinumab had longer persistence in patients who only had psoriasis, but the drug survival rate was reduced in patients with PsA. In contrast, infliximab maintained robust performance across both patient groups, with a significantly lower risk of discontinuation compared with ustekinumab (hazard ratio 0.59, 95% confidence intervals 0.53–0.67), particularly in patients with PsA. Conclusions: Drug survival differed across biologic treatments and according to PsA status. Infliximab had higher overall drug survival, particularly in patients with PsA. Ustekinumab had greater treatment persistence in patients without PsA but lower drug survival in those with PsA.

Background: Psoriasis is a chronic immune-mediated skin disease, reported to affect approximately 2–3% of the global population, with prevalence in Denmark estimated at around 5%. Objectives: To assess the long-term safety of interleukin (IL) inhibitors in relation ot secondary autoimmune diseases. Methods: Among patients with psoriasis diagnosed between 1994 and 2023, a total of 36 155 were followed during their treatment exposure (2009–2023) using data from the Danish National Patient and Prescription Registries. Exposure groups included IL inhibitors, tumour necrosis factor (TNF)-α inhibitors, and nonbiologic treatments. Different analytical approaches used in the analyses included intention-to-treat (ITT), on-treatment (OT) and continuous index treatment estimands. Hazard ratios (HRs) were calculated using Cox regression models, and supplementary analyses examined prior autoimmune disease and psoriatic arthritis (PsA) status. Results: IL inhibitors were consistently found to be associated with a lower risk of developing secondary autoimmune diseases. Based on the ITT estimand, TNF-α inhibitors were associated with a 54% increased risk [HR 1.54, 95% confidence interval (CI) 1.06–2.24] of selected autoimmune diseases. Based on the OT estimand, nonbiologic treatments were associated with an elevated risk (HR 1.57, 95% CI 1.01–2.42). Supplementary analyses including patient history of prior autoimmune disease and PsA status suggested effects in the same directions. Conclusions: The present national population-based cohort study, which included all Danish patients diagnosed with psoriasis in hospital settings between 2009 and 2023, found that IL inhibitors were not associated with a higher risk of secondary autoimmune diseases than TNF-α inhibitors and nonbiologic treatments. These findings were observed regardless of patients’ pre-existing autoimmune comorbidities. Thus, IL inhibitors were not associated with a higher risk of developing subsequent autoimmune diseases, even among patients with existing autoimmune conditions. These findings may help inform clinicians’ treatment decisions.

Healthcare transition from pediatrics to adult care is a critical yet challenging process for adolescents with long-term medical conditions. This population-based cohort study aims to present a replicable method to identify and quantify adolescents in need of comprehensive transitional care. Using data from Danish national health registers, disease complexity was categorized by expert clinicians based on diagnoses indicative of a need for comprehensive transitional care and transfer to specialized adult healthcare. The study identified 4,677 adolescents requiring comprehensive transitional care from a background population of 418,994 Danish adolescents aged 16–17 years, corresponding to 1.1%. Analysis of outpatient visit data from tertiary hospitals revealed variability in the proportion of adolescents with comprehensive transitional care needs across Denmark’s four tertiary hospitals. For instance, 11.6% of outpatient visits at Aalborg University Hospital involved a comprehensive transition-requiring diagnosis, compared to 26.7% at Copenhagen University Hospital. While the method is intentionally specific and focused on adolescents with the most complex conditions, it offers a scalable framework that could be applied across broader clinical settings. We illustrate this by also applying the method within a pediatric department-based setting. This study provides al replicable framework to assess transition care needs at a population level, primarily identifying adolescents with the most complex conditions. Broader implementation across clinical settings may refine and inform equitable transitional strategies.

Objectives: Prior studies have identified comorbidity between pediatric somatic and psychiatric diseases within specific diagnostic groups. However, population‐level data on these associations and their impact on mortality and morbidity are limited. This study aimed to examine these associations in the Danish pediatric population. Methods: We conducted a national cohort study using Danish register data, including 1,413,177 children and adolescents from 2019 to 2023. We assessed background factors, mortality, and hospital contacts across three patient groups: somatic‐only, psychiatric‐only, and somatic‐psychiatric. A new‐user design classified patients as somatic‐only or psychiatric‐only if they had no hospital contacts in the preceding 12 months. Patients with subsequent contacts for the other condition were reclassified into the somatic‐psychiatric group. Results: Most individuals were included in the somatic‐only group ( n = 532,324), with fewer in the psychiatric‐only group ( n = 21,501) or somatic‐psychiatric group ( n = 23,108). Psychiatric patients were more often boys and from lower socioeconomic backgrounds. Somatic hospital contacts often involved less severe symptoms. In contrast, psychiatric contacts involved specific diagnoses, including suicide attempts. Pediatric patients with both conditions had a higher 3‐year readmission risk (12.1%, 95% CI: 11.6%–12.6%) compared to somatic‐only patients (9.4%, 95% CI: 9.3%–9.5%), and longer average hospital stays (6.32 vs. 1.97 h). Psychiatric patients also had significantly higher all‐cause mortality. Conclusion: Somatic hospital contacts were more common, but children with psychiatric conditions faced significantly higher mortality and morbidity. These findings are relevant amid rising pediatric psychiatric diagnoses and recent Danish policy to integrate psychiatric and somatic care. Further research is needed to replicate these findings and inform optimal resource allocation for pediatric psychiatric care.

Background: This review evaluates the hypothesis of beneficial non-specific effects of the standard-titre measles vaccine. Methods: We conducted a systematic review and meta-analysis of randomised controlled trials. Trials included standard or high-titre live attenuated measles containing vaccines compared to other vaccines or placebo. The primary outcomes were mortality and morbidity. Secondary outcomes were infections, antibiotic use, atopy, allergies, asthma, and atopic dermatitis. Findings: 23 articles were included in this systematic review. Mortality: Two doses of measles vaccine vs. only one dose showed no significant effect on mortality; risk ratio (RR) = 1.05 (95% CI: 0.78 to 1.41), p = 0.76. The analysis was based on a relative risk reduction (RRR) of 25% and a control group event rate of 2.32% as measured in the actual trials included in the analysis. In males, the association was rejected: RR = 1.09 (0.86 to 1.37), p = 0.47. In females, the association was not rejected at 25%,but was at 33% level: RR = 1.0 (0.64 to 1.54), p = 0.99. Morbidity: Overall, the hypothesis was rejected: RR = 0.94 (0.80 to 1.10), p = 0.43. The rejection was sustained for both sexes: females RR = 0.95 (0.77 to 1.18), p = 0.6; males RR = 0.92 (0.83 to 1.03), p = 0.13. Interpretation: Based on evidence from randomised controlled trials, this systematic literature review and meta-analysis did not support the hypothesis of non-specific effects of standard-titre measles containing vaccines. Trial Sequential Analysis indicated that the meta-analysis included sufficient data to reach this conclusion. Trial registration: PROSPERO CRD42022344473

Background: Measles is a highly contagious viral disease, particularly severe in infants. Protection in early life is provided by maternally transferred antibodies, but this period is shorter in infants of previously vaccinated mothers (PVMs) compared to infants of previously measles-infected mothers (PIMs). Earlier measles-mumps-rubella (MMR) vaccination may compensate for this. To evaluate immune responses, 6-month-old infants were randomized to receive early MMR or placebo. This study reports the cellular immune outcomes and summarizes serological and T-cell responses.Methods: A double-blind, randomized trial involved 6540 Danish infants aged 5–7 months, eligible if birth weight exceeded 1000 grams and gestational age was ≥32 weeks. Participants were randomized 1:1 to receive M-M-RVaxPro or placebo. Blood samples were collected before intervention, four weeks after intervention, and four weeks after routine MMR at 15 months. Peripheral blood mononuclear cells (PBMCs) were prepared, and an IFN-γ specific ELISpot assay measured measles-specific T cells.Results: Among 750 infants (341 MMR, 409 placebo) in the cellular immunogenicity trial, a significant cellular immune response was observed one-month post-intervention in the MMR group compared to placebo (geometric mean ratio [GMR]: 12.3; 95% CI: 6.9–21.9). The cellular conversion rate (CCR) in the MMR group was 45%, comparable to the previously reported seroconversion rate. However, following routine MMR at 15 months, a reduced cellular response was observed in the early MMR group (GMR: 0.6; 95% CI: 0.3–0.9). Post-routine MMR, CCRs were 66% (MMR) and 74% (placebo). The immune conversion rate (ICR, defined as seroconversion and/or T-cell response) reached 99% in both groups post-routine MMR.Conclusion: Early MMR at 6 months elicited significant measles-specific cellular responses, though the CCR was lower than after routine MMR at 15 months. However, when combining serological and cellular responses, 99% of infants achieved immune conversion by 15 months. Early MMR could help reduce measles burden in infants in endemic settings without compromising subsequent immunizations.Clinical trial registration: ClinicalTrials.gov, identifier NCT03780179, EudraCT 2016-001901-18.