Estimating vaccine effectiveness against COVID-19 using cause-specific sick leave as an indicator: a nationwide population-based cohort study, Norway, July 2021 - December 2022.

BACKGROUND: Due to changes in testing policy and increased use of rapid tests, other indicators for SARS-CoV-2 infections are needed to monitor vaccine effectiveness (VE). We aimed to estimate VE against COVID-19 sick leave (> 3 days, certified by a medical professional) among employed individuals (25-64-years-old) in Norway. METHODS: We performed a nationwide cohort study by collating data from the Emergency preparedness register for COVID-19. We used adjusted Cox proportional hazard models with vaccine status as a time-varying covariate and presented results as adjusted hazard ratios (aHRs) with corresponding 95% confidence intervals. Separate models were run against sick leave and against SARS-CoV-2 infections during the Delta period (June-December 2021), and against sick leave during the Omicron period (January-December 2022) when SARS-CoV-2 PCR-testing was replaced by rapid self-tests and infections were underreported. RESULTS: We included 2,236,419 individuals during the Delta period, of whom 73,776 (3.3%) had a reported infection and 54,334 (2.4%) were registered with sick leave. Of the 2,206,952 included individuals in the Omicron period, 300,140 (13.6%) were registered with sick leave. During the Delta period, 55% (26,611) of individuals who had registered sick leave also had a positive test, compared to 32% (96,445) during the Omicron period. The VE against sick leave during the Delta period followed a similar waning pattern to that against SARS-CoV-2 infections. After the second and third dose, the lowest aHRs were estimated for 2-7 days after vaccination for both sick leave (0.25; 95%CI 0.24-0.26 and 0.26; 95% CI 0.24-0.29) and infection ( 0.16; 95% CI 0.15-0.17 and 0.18; 95% CI 0.16-0.19) respectively. During the Omicron period, aHRs for sick leave were higher than during the Delta period, but the lowest aHRs were still found in 2-7 weeks after receiving the second (0.61; 95% CI 0.59-0.64) or third dose (0.63; 95% CI 0.62-0.64). CONCLUSION: Our results showed that sick leave could be a relevant indicator for VE in the surveillance of COVID-19 and a finding that may be important in the surveillance of other respiratory infection.

The epidemiology of multidrug-resistant organisms in persons diagnosed with cancer in Norway, 2008-2018: expanding surveillance using existing laboratory and register data.

Surveillance has revealed an increase of multidrug-resistant organisms (MDROs), even in low-prevalent settings such as Norway. MDROs pose a particular threat to at-risk populations, including persons with cancer. It is necessary to include such populations in future infection surveillance. By combining existing data sources, we aimed to describe the epidemiology of MDROs in persons diagnosed with cancer in Norway from 2008 to 2018. A cohort was established using data from the Cancer Registry of Norway, which was then linked to notifications of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin- and/or linezolid-resistant enterococci (V/LRE), and carbapenemase-producing Gram-negative bacilli (CP-GNB) from the Norwegian Surveillance System for Communicable Diseases, and laboratory data on third-generation cephalosporin-resistant Enterobacterales (3GCR-E) from Oslo University Hospital (OUH). We described the incidence of MDROs and resistance proportion in Enterobacterales from 6 months prior to the person's first cancer diagnosis and up to 3 years after. The cohort included 322,005 persons, of which 0.3% (878) were diagnosed with notifiable MDROs. Peak incidence rates per 100,000 person-years were 60.9 for MRSA, 97.2 for V/LRE, and 6.8 for CP-GNB. The proportion of 3GCR-E in Enterobacterales in blood or urine cultures at OUH was 6% (746/12,534). Despite overall low MDRO incidence, there was an unfavourable trend in the incidence and resistance proportion of Gram-negative bacteria. To address this, there is a need for effective infection control and surveillance. Our study demonstrated the feasibility of expanding the surveillance of MDROs and at-risk populations through the linkage of existing laboratory and register data.

Clinical outcomes of antimicrobial resistance in cancer patients: a systematic review of multivariable models.

BACKGROUND: Infections are major causes of disease in cancer patients and pose a major obstacle to the success of cancer care. The global rise of antimicrobial resistance threatens to make these obstacles even greater and hinder continuing progress in cancer care. To prevent and handle such infections, better models of clinical outcomes building on current knowledge are needed. This internally funded systematic review (PROSPERO registration: CRD42021282769) aimed to review multivariable models of resistant infections/colonisations and corresponding mortality, what risk factors have been investigated, and with what methodological approaches. METHODS: We employed two broad searches of antimicrobial resistance in cancer patients, using terms associated with antimicrobial resistance, in MEDLINE and Embase through Ovid, in addition to Cinahl through EBSCOhost and Web of Science Core Collection. Primary, observational studies in English from January 2015 to November 2021 on human cancer patients that explicitly modelled infection/colonisation or mortality associated with antimicrobial resistance in a multivariable model were included. We extracted data on the study populations and their malignancies, risk factors, microbial aetiology, and methods for variable selection, and assessed the risk of bias using the NHLBI Study Quality Assessment Tools. RESULTS: Two searches yielded a total of 27,151 unique records, of which 144 studies were included after screening and reading. Of the outcomes studied, mortality was the most common (68/144, 47%). Forty-five per cent (65/144) of the studies focused on haemato-oncological patients, and 27% (39/144) studied several bacteria or fungi. Studies included a median of 200 patients and 46 events. One-hundred-and-three (72%) studies used a p-value-based variable selection. Studies included a median of seven variables in the final (and largest) model, which yielded a median of 7 events per variable. An in-depth example of vancomycin-resistant enterococci was reported. CONCLUSIONS: We found the current research to be heterogeneous in the approaches to studying this topic. Methodological choices resulting in very diverse models made it difficult or even impossible to draw statistical inferences and summarise what risk factors were of clinical relevance. The development and adherence to more standardised protocols that build on existing literature are urgent.

High vaccine effectiveness against coronavirus disease 2019 (COVID-19) and severe disease among residents and staff of long-term care facilities in Norway, November 2020-June 2021.

Coronavirus disease 2019 (COVID-19) causes high morbidity and mortality in long-term care facilities (LTCFs). COVID-19 vaccine effectiveness against infection was 81.5% and 81.4% among fully vaccinated residents and staff in LTCFs. The vaccine effectiveness against COVID-19-associated death was 93.1% among residents, and no hospitalizations occurred among fully vaccinated staff.

Age and product dependent vaccine effectiveness against SARS-CoV-2 infection and hospitalisation among adults in Norway: a national cohort study, July-November 2021.

BACKGROUND: COVID-19 vaccines have been crucial in the pandemic response and understanding changes in vaccines effectiveness is essential to guide vaccine policies. Although the Delta variant is no longer dominant, understanding vaccine effectiveness properties will provide essential knowledge to comprehend the development of the pandemic and estimate potential changes over time. METHODS: In this population-based cohort study, we estimated the vaccine effectiveness of Comirnaty (Pfizer/BioNTech; BNT162b2), Spikevax (Moderna; mRNA-1273), Vaxzevria (AstraZeneca; ChAdOx nCoV-19; AZD1222), or a combination against SARS-CoV-2 infections, hospitalisations, intensive care admissions, and death using Cox proportional hazard models, across different vaccine product regimens and age groups, between 15 July and 31 November 2021 (Delta variant period). Vaccine status is included as a time-varying covariate and all models were adjusted for age, sex, comorbidities, county of residence, country of birth, and living conditions. Data from the entire adult Norwegian population were collated from the National Preparedness Register for COVID-19 (Beredt C19). RESULTS: The overall adjusted vaccine effectiveness against infection decreased from 81.3% (confidence interval (CI): 80.7 to 81.9) in the first 2 to 9 weeks after receiving a second dose to 8.6% (CI: 4.0 to 13.1) after more than 33 weeks, compared to 98.6% (CI: 97.5 to 99.2) and 66.6% (CI: 57.9 to 73.6) against hospitalisation respectively. After the third dose (booster), the effectiveness was 75.9% (CI: 73.4 to 78.1) against infection and 95.0% (CI: 92.6 to 96.6) against hospitalisation. Spikevax or a combination of mRNA products provided the highest protection, but the vaccine effectiveness decreased with time since vaccination for all vaccine regimens. CONCLUSIONS: Even though the vaccine effectiveness against infection waned over time, all vaccine regimens remained effective against hospitalisation after the second vaccine dose. For all vaccine regimens, a booster facilitated recovery of effectiveness. The results from this support the use of heterologous schedules, increasing flexibility in vaccination policy.

Register-based surveillance of COVID-19 in nursing homes. / Registerbasert overvåkning av covid-19 i sykehjem.

BACKGROUND: This study describes results from the surveillance of COVID-19 infections in nursing homes in the first year of the COVID-19 pandemic. MATERIAL AND METHOD: All data in the study are from Beredt C19, an emergency preparedness register that collects data from a wide range of sources. We used the data set 'Health and Care' in the Norwegian Registry for Primary Health Care to define a nursing home population and linked this to other sources in the emergency preparedness register to estimate incidence rates, hospitalisations and deaths related to COVID-19 among nursing home residents in 2020. A log-binomial regression model was used to analyse the risk of death related to COVID-19. RESULTS: Of the 83 114 persons who were included in the study, 35 758 (43 %) were older than 80 years. We found that 570 persons (0.69 %) tested positive for SARS-CoV-2 in 2020. A total of 19 041 residents died during the study period, whereof 248 (1.3 %) deaths were related to COVID-19. The relative risk of dying from COVID-19 rose with age and was highest for long-term nursing home residents. INTERPRETATION: Nursing home residents have a high background mortality, so despite the high lethality of SARS-CoV-2 infection and the high proportion of the COVID-19-related deaths that have occurred in nursing homes, COVID-19-related deaths accounted for a relatively minor proportion of all deaths among nursing home residents.

Treatment of Ductal Carcinoma in situ: A Register-Based Study of Norwegian Women Diagnosed between 1995 and 2018.

Introduction: The incidence of ductal carcinoma in situ (DCIS) has increased after implementation of mammographic screening. The lesion represents management challenges due to its undetermined growth pattern. We aimed to explore treatment of women aged 48-71 years diagnosed with DCIS between 1995 and 2018, by detection mode and histopathological characteristics. Material and Methods: Data on surgical treatment and radiation therapy (RT) of 4,995 women diagnosed with DCIS were retrieved from the Cancer Registry of Norway. We described the percentage and frequency of breast-conserving treatment (BCT) for participants in BreastScreen Norway (screen-detected) and nonparticipants. We estimated the relative risk (RR) of BCT, using log-binomial regression models. Results: Use of BCT increased from about 40% in 1995 to 85% in 2018. Use of BCT was more common among older than younger women and more commonly used for screen-detected versus tumors detected outside the screening program. Nine out of ten women with tumors ≤10 mm were treated with BCT and two out of ten with tumors >50 mm. RT was given to 89.3% of the women with tumors ≤10 mm, 34.1% of those with tumors classified as van Nuys' grade 1 and <10 mm and 96.0% of the tumors >50 mm. Use of BCT was less common for tumors >50 mm compared to <10 mm (RR adjusted for age, detection mode, van Nuys' grade, and localization: 0.26, 95% CI: 0.19-0.36). Conclusion: BCT was increasingly used among women diagnosed with DCIS in Norway during the period from 1995 to 2018, particularly for screen-detected, small lesions with low van Nuys' grade.

Birthing parents had a lower risk of testing positive for SARS-CoV-2 in the peripartum period in Norway, 15th of February 2020 to 15th of May 2021.

Hospital infection control measures against COVID-19 may come into conflict with patients' need for support. In Norway, some hospitals have restricted access for partners of women giving birth. We investigated the incidence rate of SARS-CoV-2 among birthing parents compared to similarly aged women and men in the general population; and the additional risk posed by allowing partners in. Birthing parents often shared infection status and had a slightly lower incidence rate than the general population in the peripartum period. They should not be considered a high-risk group for SARS-CoV-2 infections.

Vaccine effectiveness against infection with the Delta (B.1.617.2) variant, Norway, April to August 2021.

Some variants of SARS-CoV-2 are associated with increased transmissibility, increased disease severity or decreased vaccine effectiveness (VE). In this population-based cohort study (n = 4,204,859), the Delta variant was identified in 5,430 (0.13%) individuals, of whom 84 were admitted to hospital. VE against laboratory confirmed infection with the Delta variant was 22.4% among partly vaccinated (95% confidence interval (CI): 17.0-27.4) and 64.6% (95% CI: 60.6-68.2) among fully vaccinated individuals, compared with 54.5% (95% CI: 50.4-58.3) and 84.4% (95%CI: 81.8-86.5) against the Alpha variant.

Assessment of breast positioning criteria in mammographic screening: Agreement between artificial intelligence software and radiographers.

OBJECTIVES: To determine the agreement between artificial intelligence software (AI) and radiographers in assessing breast positioning criteria for mammograms from standard digital mammography and digital breast tomosynthesis. METHODS: Assessment of breast positioning was performed by AI and by four radiographers in pairs of two on 156 examinations of women screened in Bergen, April to September 2019, as part of BreastScreen Norway. Ten criteria were used; three for craniocaudal and seven for mediolateral-oblique view. The criteria evaluated the appearance of the nipple, breast rotation, pectoral muscle, inframammary fold and pectoral nipple line. Intraclass correlation and Cohen's kappa coefficient (κ) were used to investigate the correlation and agreement between the radiographer's assessments and AI. RESULTS: The intraclass correlation for the pectoral nipple line between the radiographers and AI was >0.92. A substantial to almost perfect agreement (κ > 0.69) was observed between the radiographers and AI on the nipple in profile criterion. We observed a slight to moderate agreement for the other criteria (κ = 0.06-0.52) and generally a higher agreement between the two pairs of radiographers (mean κ = 0.70) than between the radiographers and AI (mean κ = 0.41). CONCLUSIONS: AI has great potential in evaluating breast position criteria in mammography by reducing subjectivity. However, varying agreement between radiographers and AI was observed. Standardized and evidence-based criteria for definitions, understandings and assessment methods are needed to reach optimal image quality in mammography.

SARS-CoV-2 in health and care staff in Norway, 2020. / SARS-CoV-2 blant ansatte i helse- og omsorgstjenesten.

BACKGROUND: The COVID-19 pandemic is placing considerable pressure on health services around the world. In Norway, the incidence rate among the working-age population (20-69 years) for the whole of 2020 was 1.11 %. In this study, we describe diagnosed infection among staff in the health service, based on register data. MATERIAL AND METHOD: From the emergency preparedness register, Beredt C19, we identified 382 332 persons employed in selected occupational groups in the health service in week 9 of 2020, and investigated incidence and testing activity for diagnosed SARS-CoV-2 according to occupation, age, sex, country of birth, place of residence and place of work, for the whole of 2020. RESULTS: The incidence in the health service for the entire period was 1.48 % (5673/382 332). Diagnosed infection was highest among ambulance personnel and nursing home staff, with an incidence of 1.83 % (95/5203) and 1.86 % (1534/82 776), respectively. Doctors were tested most frequently (1.45 tests per person), and the proportion of positive tests was highest among cleaners (2.78 %) and ambulance personnel (1.57 %). Imported infection was highest for dentists (14.3 %), psychologists (12.8 %) and doctors (10.8 %). INTERPRETATION: There are variations in the incidence of diagnosed infections among employees in the health service. Some of this can likely be viewed in connection with high testing activity, imported infection, age and sex distribution, place of residence and country of birth, and outbreaks in different health services. More research and data are needed to ascertain whether occupational practice is associated with increased risk of SARS-CoV-2 infection.

Self-reported Pain Associated With Screening With Digital Breast Tomosynthesis.

OBJECTIVE: We aimed to investigate self-reported pain during screening with digital breast tomosynthesis (DBT). METHODS: The study was approved by the Regional Committee for Medical and Health Research Ethics in the South East of Norway (2015/424). Women completed a questionnaire about experienced pain directly after the examination, August-November 2019. A numeric rating scale (NRS, 0-10) was used. Data on compression force (N), pressure (kPa), and compressed breast thickness (mm) were obtained from the Digital Imaging and Communication in Medicine header and density assessment software. Stepwise ordinary least-squares regression was used to estimate mean self-reported pain score with 95% confidence interval (CI) for values of compression force, pressure, and compressed breast thickness. RESULTS: The mean pain score was 1.9, whereof 19.3% (822/4266) of the women reported moderate or severe pain. The mean pain score of 2.6 (95% CI: 2.4-2.7) was observed at a compression force of 60 N, decreasing to 1.3 (95% CI: 1.2-1.4) at 130 N. The mean pain score of 1.3 (95% CI: 1.1-1.4) was at a compression pressure of 6 kPa, increasing to 2.9 (95% CI: 2.7-3.1) at 16 kPa. The mean pain score was 0.6 (95% CI: 0.4-0.6) at a compressed breast thickness of 20 mm, increasing to 2.9 (95% CI: 2.7-3.1) at 90 mm. CONCLUSION: The mean pain score was low, 1.9 on NRS, for women screened with DBT. A compression force of 60-130 N and a pressure 6-16 kPa were associated with no or mild pain.

Surgical treatment of breast cancer in Norway 2003-2018. / Kirurgisk behandling av brystkreft i Norge 2003­18.

BACKGROUND: Breast-conserving surgery is recommended in Norway and internationally in cases of early-stage breast cancer. We analysed the surgical methods used for breast-cancer patients by hospital providing treatment, age at the time of diagnosis, detection method and histopathological characteristics of the tumours in the period 2003 to 2018. MATERIAL AND METHOD: Data on women of all ages diagnosed with invasive breast cancer (n = 47 004) were retrieved from the Cancer Registry of Norway's databases. We excluded women with distant metastases at the time of diagnosis (n = 1 773) and those for whom no surgical method was recorded (n = 2 638). The detection method was defined as breast cancer detected by screening, in inter-screening intervals, or outside BreastScreen Norway. The surgical methods chosen were compared by means of descriptive analyses. RESULTS: Slightly over half (23 661 of 42 593, i.e. 55.6 %) of the women in whom breast cancer was detected in the study period underwent breast-conserving surgery. The percentage increased from 1 189/2 423 (49.1 %) in 2003 to 2 070/2 958 (70.0 %) in 2018. There were large differences across hospitals. In the period 2015-2018 we found the highest proportion of breast-conserving surgery, 175/187 (93.6 %) for breast cancer detected by screening to be performed at Ålesund Hospital, and the lowest proportion, 121/351 (34.5 %) among women with breast cancer detected outside BreastScreen Norway, to be performed at Radiumhospitalet. Breast-conserving surgery was used most frequently on women with small tumours without spreading to axillary lymph nodes. INTERPRETATION: We found considerable differences in the surgical methods used across hospitals and for different detection methods.

Asylum seekers' health and use of health services in Norway. / Asylsøkeres helse og bruk av helsetjenester i Norge.

BACKGROUND: Many asylum seekers arrived in Norway during autumn 2015, and there has been a call for more knowledge regarding the health of this group. The aim of this exploratory literature review was to investigate the state of knowledge about asylum seekers' health and use of healthcare services in Norway. MATERIAL AND METHOD: We conducted two literature searches for the periods 2007-2017 and 2017-2019 in 12 databases using the keywords 'refugees' and related terms, with a filter for research undertaken in or about Norway and published in Norwegian or English. The title and summary were read first, after which relevant articles were read in full text. Publications concerning asylum seekers in Norway and related to health and/or use of health services were included. RESULTS: A total of 28 publications met the criteria for inclusion: 22 peer-reviewed articles and six reports. The most common topics were mental health and infectious diseases. Other topics that the studies dealt with were nutrition, functional impairment and healthcare services. INTERPRETATION: Little research has been undertaken on asylum seekers' health and use of healthcare services. Research on asylum seekers' health in Norway primarily concerns mental health and infectious diseases, and there is little research on other somatic disorders.

Targeting TB or MRSA in Norwegian municipalities during 'the refugee crisis' of 2015: a framework for priority setting in screening.

IntroductionIn 2015, there was an increase in the number of asylum seekers arriving in Europe. Like in other countries, deciding screening priorities for tuberculosis (TB) and meticillin-resistant Staphylococcus aureus (MRSA) was a challenge. At least five of 428 municipalities chose to screen asylum seekers for MRSA before TB; the Norwegian Institute for Public Health advised against this.AimTo evaluate the MRSA/TB screening results from 2014 to 2016 and create a generalised framework for screening prioritisation in Norway through simulation modelling.MethodsThis is a register-based cohort study of asylum seekers using data from the Norwegian Surveillance System for Communicable Diseases from 2014 to 2016. We used survey data from municipalities that screened all asylum seekers for MRSA and denominator data from the Directorate of Immigration. A comparative risk assessment model was built to investigate the outcomes of prioritising between TB and MRSA in screening regimes.ResultsOf 46,090 asylum seekers, 137 (0.30%) were diagnosed with active TB (notification rate: 300/100,000 person-years). In the municipalities that screened all asylum seekers for MRSA, 13 of 1,768 (0.74%) were found to be infected with MRSA. The model estimated that screening for MRSA would prevent eight MRSA infections while prioritising TB screening would prevent 24 cases of active TB and one death.ConclusionOur findings support the decision to advise against screening for MRSA before TB among newly arrived asylum seekers. The model was an effective tool for comparing screening priorities and can be applied to other scenarios in other countries.