Follow-Up Study of Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against All-Type and Serotype-Specific Invasive Pneumococcal Disease, Denmark.

As a follow-up to a previous study, we investigated vaccine effectiveness (VE) of 23-valent pneumococcal polysaccharide vaccine (PPSV23) against invasive pneumococcal disease (IPD) among 1,254,498 persons >65 years of age as part of a vaccination program in Denmark during April 2020-January 2023. We assessed VE by using a Cox regression model and adjusted for age, sex, and underlying conditions. Using nationwide data, we estimated a VE of PPSV23 against all-type IPD of 32% and against PPSV23-serotype IPD of 41%. Because this follow-up study had more statistical power than the original study, we also estimated VE against IPD caused by PPSV23-serotypes excluding serotype 3; serotype 3; serotype 8; serotype 22F; PPSV23 non-PCV15 serotypes; PPSV23 non-PCV20 serotypes; and IPD over time. Our findings suggest PPSV23 vaccination can protect persons >65 years of age against IPD caused by all serotypes or serotype groupings, except serotype 3.

Pertussis epidemic in Denmark, August 2023 to February 2024.

We report a record high pertussis epidemic in Denmark since August 2023. Highest incidence was in adolescents, while peak incidence in infants was lower vs previous epidemics in 2019 and 2016. Among infants aged 0-2 months, over half (29/48) were hospitalised and one infant died, underlining the disease severity in the youngest. To protect infants, pertussis vaccination in pregnant women was introduced in January 2024 in the national vaccination programme. Improved vaccination surveillance in pregnant women is being implemented.

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease among 948,263 individuals ≥ 65 years of age: a Danish cohort study.

This study aimed to estimate the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) against invasive pneumococcal disease (IPD) among individuals ≥ 65 years of age. We used Danish nationwide databases to obtain information on PPV23 vaccination, covariates, and IPD and linked data on an individual level using a unique personal identifier. A total of 948,263 individuals were included and followed between June 15, 2020, and September 18, 2021 (58.6% were vaccinated during follow-up). The adjusted vaccine effectiveness was 42% (95% confidence interval (CI): 9-63%) for all-serotype IPD and 58% (95% CI: 21-78%) for PPV23-serotype IPD, using no vaccination as the reference.

Increased transmission of SARS-CoV-2 in Denmark during UEFA European championships.

Denmark hosted four games during the 2020 UEFA European championships (EC2020). After declining positive SARS-CoV-2 test rates in Denmark, a rise occurred during and after the tournament, concomitant with the replacement of the dominant Alpha lineage (B.1.1.7) by the Delta lineage (B.1.617.2), increasing vaccination rates and cessation of several restrictions. A cohort study including 33 227 cases was conducted from 30 May to 25 July 2021, 14 days before and after the EC2020. Included was a nested cohort with event information from big-screen events and matches at the Danish national stadium, Parken (DNSP) in Copenhagen, held from 12 June to 28 June 2021. Information from whole-genome sequencing, contact tracing and Danish registries was collected. Case-case connections were used to establish transmission trees. Cases infected on match days were compared to cases not infected on match days as a reference. The crude incidence rate ratio (IRR) of transmissions was 1.55, corresponding to 584 (1.76%) cases attributable to EC2020 celebrations. The IRR adjusted for covariates was lower (IRR 1.41) but still significant, and also pointed to a reduced number of transmissions from fully vaccinated cases (IRR 0.59). These data support the hypothesis that the EC2020 celebrations contributed to the rise of cases in Denmark in the early summer of 2021.

First-Line Treatment of HER2-Positive Metastatic Breast Cancer With Dual Blockade Including Biosimilar Trastuzumab (SB3): Population-Based Real-World Data From the DBCG.

Purpose: Dual blockade with trastuzumab and pertuzumab in combination with chemotherapy is the recommended first-line therapy for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC). The purpose of this retrospective study is to examine the clinical outcomes of the trastuzumab biosimilar SB3 in first-line dual blockade treatment using real-world data of patients with HER-positive mBC. Methods: In Denmark, all women with breast cancer are registered in the database of the Danish Breast Cancer Group (DBCG). From this prospective observational registry, we extracted information on primary diagnosis and treatment of all women with HER2-positive mBC who received first-line treatment with SB3 and pertuzumab from September 1, 2018, to February 29, 2020. Retrospectively collected data from the DBCG database included information concerning treatment start, end, and reason for discontinuation. The primary endpoints for the study were overall survival (OS) and progression-free survival (PFS). Results: The study included 117 women who received first-line treatment with SB3 and pertuzumab for their HER2-positive mBC. The study population had a mean age of 60 years. A total of 71 patients (61%) had recurrent disease and 46 patients (39%) presented with de novo mBC. The median follow-up was 11.1 and 15.4 months for PFS and OS, respectively. At 12 months, OS was 84% (95% confidence interval [CI], 78-91), whereas the median OS was not reached. The median PFS was 12.7 months (95% CI, 11.1-16.2). Median time on treatment was 8.7 months (95% CI, 7.6-11.4); 36 patients (31%) were still on treatment at end of study. Conclusions: This retrospective real-world, nationwide study demonstrated comparable median PFS to the historical data of using reference trastuzumab and pertuzumab as first-line dual blockade.

Dual HER2 blockade in the first-line treatment of metastatic breast cancer - A retrospective population-based observational study in Danish patients.

OBJECTIVES: Randomized clinical trials do not include a population that truly reflects a real-world population, due to their inclusion and exclusion criteria. This leads to concerns about the applicability of these studies in a clinical practice. In the present study, we aim to describe the clinical and demographic characteristics, treatment patterns, and clinical outcomes in a population of patients with HER2-positive metastatic breast cancer who received pertuzumab and trastuzumab as first-line treatment in a real-world setting. METHODS: The database of the Danish Breast Cancer Group was used to assemble data on patients included in the period April 2013 to August 2017. The primary endpoints were overall survival (OS) and progression-free survival (PFS). RESULTS: A cohort of 291 patients with a median age of 58 years was registered. Hereof 112 (38%) patients with de novo disease (primary disseminated) and 179 (62%) with recurrence. The median follow-up for OS was 24.1 months. The median OS was 41.8 months (95% CI, 37.7 to NE) and the median PFS was 15.8 months (95% CI, 14.0 to 19.9). For de novo patients alone, the median OS was not reached whereas the median PFS was 17.9 months (95% CI, 14.3 to 27.3). Hazard ratios for patients receiving vinorelbine showed comparable results as for the whole population. CONCLUSION: This heterogeneous patient population in a real-world setting had a PFS comparable with what could be expected from the related randomized trial. The de novo patients had better OS and PFS as compared to patients with recurrence.