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Nina Gran Egeland,1,2 Kristin Jonsdottir,1 Kristina Lystlund Lauridsen,3 Ivar Skaland,1 Cathrine F Hjorth,4 Einar G Gudlaugsson,1 Stephen Hamilton-Dutoit,3 Timothy L Lash,4,5 Deirdre Cronin-Fenton,4,* Emiel AM Janssen1,2,* 1Department of Pathology, Stavanger University Hospital, Stavanger, Norway; 2Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, Stavanger, Norway; 3Institute of Pathology, Aarhus University Hospital, Aarhus, Denmark; 4Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 5Department of Epidemiology, Rollins School of Public Health and Winship Cancer Institute, Emory University, Atlanta, GA, USA*These authors contributed equally to this workCorrespondence: Nina Gran EgelandDepartment of Pathology, Stavanger University Hospital, Box 8100, Stavanger 4068, NorwayTel +47 924 25 622Email nina.gran.egeland@sus.noPurpose: The proliferation marker Ki-67 has been used as a prognostic marker to separate low- and high-risk breast cancer subtypes and guide treatment decisions for adjuvant chemotherapy. The association of Ki-67 with response to tamoxifen therapy is unclear. High-throughput automated scoring of Ki-67 might enable standardization of quantification and definition of clinical cut-off values. We hypothesized that digital image analysis (DIA) of Ki-67 can be used to evaluate proliferation in breast cancer tumors, and that Ki-67 may be associated with tamoxifen resistance in early-stage breast cancer.Patients and Methods: Here, we apply DIA technology from Visiopharm using a custom designed algorithm for quantifying the expression of Ki-67, in a case–control study nested in the Danish Breast Cancer Group clinical database, consisting of stages I, II, or III breast cancer patients of 35– 69 years of age, diagnosed during 1985– 2001, in the Jutland peninsula, Denmark. We assessed DIA-Ki-67 score on tissue microarrays (TMAs) from breast cancer patients in a case–control study including 541 ER-positive and 300 ER-negative recurrent cases and their non-recurrent controls, matched on ER-status, cancer stage, menopausal status, year of diagnosis, and county of residence. We used logistic regression to estimate odds ratios and associated 95% confidence intervals to determine the association of Ki-67 expression with recurrence risk, adjusting for matching factors, chemotherapy, type of surgery, receipt of radiation therapy, age category, and comorbidity.Results: Ki-67 was not associated with increased risk of recurrence in tamoxifen-treated patients (ORadj =0.72, 95% CI 0.54, 0.96) or ER-negative patients (ORadj =0.85, 95% CI 0.54, 1.34).Conclusion: Our findings suggest that Ki-67 digital image analysis in TMAs is not associated with increased risk of recurrence among tamoxifen-treated ER-positive breast cancer or ER-negative breast cancer patients. Overall, our findings do not support an increased risk of recurrence associated with Ki-67 expression.Keywords: breast cancer, tamoxifen, proliferation, Ki-67, recurrence risk, tissue microarray, TMA, digital image analysis, DIA

Objective: To evaluate two automated amplification systems for the detection of Chlamydia trachomatis in urogenital specimens, the Cobas Amplicor (Roche Diagnostic Systems, Branchburg, NJ) and the LCx (Abbott Laboratories, Abbott Park, IL).Study Design: The two systems were compared testing specimens from 302 high-risk patients, including 98 female cervical swab specimens and 204 male urine specimens. The patients attended the state STD clinic in Reykjavik, Iceland, either because of symptoms or as a result of contract tracing.Results: The prevalence of C. trachomatis infection was 15.3% in women and 13.2% in men. For the male urine specimens, the sensitivity and specificity were 100% and 99.4% for the Cobas Amplicor and 74.1% and 100% for the LCx. In the cervical swabs, both systems detected all 15 true-positive specimens. The internal control used with the Cobas Amplicor detected inhibition in 2% of the male urine and 20% female cervical swabs, respectively.Conclusion: The Cobas Amplicor demonstrated slightly better sensitivity than LCx in male urine specimens. Both systems offer the benefits of automation for routine diagnostic testing. [ABSTRACT FROM AUTHOR]

Many examples of exposed giant dike swarms can be found where lateral magma flow has exceeded hundreds of kilometers. We show that massive magma flow into dikes can be established with only modest overpressure in a magma body if a large enough pathway opens at its boundary and gradual buildup of high tensile stress has occurred along the dike pathway prior to the onset of diking. This explains rapid initial magma flow rates, modeled up to about 7400 cubic meters per second into a dike ~15-kilometers long, which propagated under the town of Grindavík, Southwest Iceland, in November 2023. Such high flow rates provide insight into the formation of major dikes and imply a serious hazard potential for high-flow rate intrusions that propagate to the surface and transition into eruptions.

Cyanobacteria have demonstrated their therapeutic potential for many human diseases. In this work, cyanobacterial extracts were screened for lipid reducing activity in zebrafish larvae and in fatty-acid-overloaded human hepatocytes, as well as for glucose uptake in human hepatocytes and ucp1 mRNA induction in murine brown adipocytes. A total of 39 cyanobacteria strains were grown and their biomass fractionated, resulting in 117 chemical fractions. Reduction of neutral lipids in zebrafish larvae was observed for 12 fractions and in the human hepatocyte steatosis cell model for five fractions. The induction of ucp1 expression in murine brown adipocytes was observed in six fractions, resulting in a total of 23 bioactive non-toxic fractions. All extracts were analyzed by untargeted UPLC-Q-TOF-MS mass spectrometry followed by multivariate statistical analysis to prioritize bioactive strains. The metabolite profiling led to the identification of two markers with lipid reducing activity in zebrafish larvae. Putative compound identification using mass spectrometry databases identified them as phosphatidic acid and aromatic polyketides derivatives-two compound classes, which were previously associated with effects on metabolic disorders. In summary, we have identified cyanobacterial strains with promising lipid reducing activity, whose bioactive compounds needs to be identified in the future.

Increased rates of deformation and seismicity are well-established precursors to volcanic eruptions, and their interpretation forms the basis for eruption warnings worldwide. Rates of ground displacement and the number of earthquakes escalate before many eruptions 1-3 , as magma forces its way towards the surface. However, the pre-eruptive patterns of deformation and seismicity vary widely. Here we show how an eruption beginning on 19 March 2021 at Fagradalsfjall, Iceland, was preceded by a period of tectonic stress release ending with a decline in deformation and seismicity over several days preceding the eruption onset. High rates of deformation and seismicity occurred from 24 February to mid-March in relation to gradual emplacement of an approximately 9-km-long magma-filled dyke, between the surface and 8 km depth (volume approximately 34 × 10 6  m 3 ), as well as the triggering of strike-slip earthquakes up to magnitude M W 5.64. As stored tectonic stress was systematically released, there was less lateral migration of magma and a reduction in both the deformation rates and seismicity. Weaker crust near the surface may also have contributed to reduced seismicity, as the depth of active magma emplacement progressively shallowed. This demonstrates that the interaction between volcanoes and tectonic stress as well as crustal layering need to be fully considered when forecasting eruptions., (© 2022. The Author(s).)

Background: Every year, millions of children undergo medical procedures that require anesthesia. Fear and anxiety are common among young children undergoing such procedures and can interfere with the child's recovery and well-being. Relaxation, distraction, and education are methods that can be used to prepare children and help them cope with fear and anxiety, and serious games may be a suitable medium for these purposes. User-centered design emphasizes the involvement of end users during the development and testing of products, but involving young, preschool children may be challenging., Objective: One objective of this study was to describe the development and usability of a computer-based educational health game intended for preschool children to prepare them for upcoming anesthesia. A further objective was to describe the lessons learned from using a child-centered approach with the young target group., Methods: A formative mixed methods child (user)-centered study design was used to develop and test the usability of the game. Preschool children (4-6 years old) informed the game design through playful workshops (n=26), and usability testing was conducted through game-playing and interviews (n=16). Data were collected in Iceland and Finland with video-recorded direct observation and interviews, as well as children's drawings, and analyzed with content analysis and descriptive statistics., Results: The children shared their knowledge and ideas about hospitals, different emotions, and their preferences concerning game elements. Testing revealed the high usability of the game and provided important information that was used to modify the game before publishing and that will be used in its further development., Conclusions: Preschool children can inform game design through playful workshops about health-related subjects that they are not necessarily familiar with but that are relevant for them. The game's usability was improved with the participation of the target group, and the game is now ready for clinical testing., (©Brynja Ingadottir, Elina Laitonen, Adalheidur Stefansdottir, Anna Olafia Sigurdardottir, Berglind Brynjolfsdottir, Heidi Parisod, Johanna Nyman, Karitas Gunnarsdottir, Katrín Jónsdóttir, Sanna Salanterä, Anni Pakarinen. Originally published in JMIR Serious Games (https://games.jmir.org), 20.01.2022.)

Large volume effusive eruptions with relatively minor observed precursory signals are at odds with widely used models to interpret volcano deformation. Here we propose a new modelling framework that resolves this discrepancy by accounting for magma buoyancy, viscoelastic crustal properties, and sustained magma channels. At low magma accumulation rates, the stability of deep magma bodies is governed by the magma-host rock density contrast and the magma body thickness. During eruptions, inelastic processes including magma mush erosion and thermal effects, can form a sustained channel that supports magma flow, driven by the pressure difference between the magma body and surface vents. At failure onset, it may be difficult to forecast the final eruption volume; pressure in a magma body may drop well below the lithostatic load, create under-pressure and initiate a caldera collapse, despite only modest precursors.

Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption. We use multiparameter geophysical and geochemical data to show that the 110-square-kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014-2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption., (Copyright © 2016, American Association for the Advancement of Science.)

Crust at many divergent plate boundaries forms primarily by the injection of vertical sheet-like dykes, some tens of kilometres long. Previous models of rifting events indicate either lateral dyke growth away from a feeding source, with propagation rates decreasing as the dyke lengthens, or magma flowing vertically into dykes from an underlying source, with the role of topography on the evolution of lateral dykes not clear. Here we show how a recent segmented dyke intrusion in the Bárðarbunga volcanic system grew laterally for more than 45 kilometres at a variable rate, with topography influencing the direction of propagation. Barriers at the ends of each segment were overcome by the build-up of pressure in the dyke end; then a new segment formed and dyke lengthening temporarily peaked. The dyke evolution, which occurred primarily over 14 days, was revealed by propagating seismicity, ground deformation mapped by Global Positioning System (GPS), interferometric analysis of satellite radar images (InSAR), and graben formation. The strike of the dyke segments varies from an initially radial direction away from the Bárðarbunga caldera, towards alignment with that expected from regional stress at the distal end. A model minimizing the combined strain and gravitational potential energy explains the propagation path. Dyke opening and seismicity focused at the most distal segment at any given time, and were simultaneous with magma source deflation and slow collapse at the Bárðarbunga caldera, accompanied by a series of magnitude M > 5 earthquakes. Dyke growth was slowed down by an effusive fissure eruption near the end of the dyke. Lateral dyke growth with segment barrier breaking by pressure build-up in the dyke distal end explains how focused upwelling of magma under central volcanoes is effectively redistributed over long distances to create new upper crust at divergent plate boundaries.

Introduction: In late 2007, the availability of immediate breast reconstructions increased as a result of the establishment of an oncoplastic breast surgical service at Landspítali-The National University Hospital The aim of this study was to look at the rates and early complications of immediate breast reconstructions in our hospital in 2008-2010 and compare with the results from the UK National Mastectomy and Breast Reconstruction Audit (NMBRA)., Material and Methods: This is a retrospective population-based study, including all women who had immediate breast reconstruction at Landspítali in 2008-2010., Results: 319 mastectomies and 157 breast reconstructions were performed. Of these, 98 (62%) were immediate, (mean age 49, 29-69). The immediate breast reconstruction rate was therefore 31%, with a respective 55% for patients 50 years old or younger. In comparison, the rate was 5% in 2000-2005. Immediate reconstructions with an extended autologous latissimus dorsi flap were performed in 25 (26%) cases and implant based reconstructions in the remaining (n=73, 74%). Inpatient complications occurred in 12 (12%) patients and 5 needed reoperation (3 post-operative bleeding, 1 skin necrosis, 1 imminent LD-flap failure). Readmission due to complications after discharge occurred in 14 (14%), while 37 (38%) developed mild complications not requiring readmission. The results were comparable to NMBRA, although the rates of autologous flap reconstructions were significantly higher than in this study (63% vs. 26%)., Conclusion: As a result of the establishment of an oncoplastic breast surgical service at Landspítali, the rates of immediate breast reconstruction have increased significantly (from 5% to 31%). The complication rates are low and similar to NMBRA.

An important feature in "Good Biobanking Practices" is to monitor and log conditions of sample storing devices. The Institute of Laboratory Medicine at Landspitali University Hospital in Reykjavik, Iceland, has installed a temperature monitoring and alarm system for freezers, incubators, and refrigerators as a part of its quality program. This paper describes the key features of the system, how it works, and what has been learned.

Objective: Medical abortion is a safe and effective treatment and is increasingly being used for termination of early pregnancy. In February 2006 medical abortion became available to women in Iceland. The purpose of this study is to assess the efficacy of medical abortion and evaluate whether it is a suitable alternative to surgical abortion in Iceland., Material and Methods: All eligible women (pregnancy <63 days, n=246) who chose medical abortion from February 2006 until July 2007 were included in the study. Data was collected on those who needed surgical evacuation and on other complications., Results: The proportion of women who had medical abortion was 17.4% (n=246/1171). Curettage was needed in 8.9% of cases. Antibiotics were prescribed in 4.1% of cases and four women were admitted for complications without need for evacuation (urinary tract infection=2, bleeding=2), one woman was admitted to the intensive care unit for 24 hours because of unexplained fever and one woman needed blood transfusion., Conclusion: The success rate of more than 90% is comparable to what has been reported in other studies (92-99%) and this treatment option has proven to be safe in our settings. In total 17.4% of women opting for abortion had a medical abortion compared to 50% in Sweden and 46% in Denmark. With more experience and general awareness of the possibilities of medical abortion the ratio is likely to increase.

Objective: Fluoroquinolones are bacteriocidal drugs that are widely used to treat severe urinary and respiratory tract infections. Studies show that resistance to fluoroquinolones is continuously increasing both in Europe and the United States. The purpose of this study was to measure the frequency of fluoroquinolone resistance in the most prevalent Gram negative rods and look at the correlation with fluoroquinolone use over the last 8 years., Materials and Methods: All strains of Escherichia coli, Klebsiella sp., Proteus sp. and Pseudomonas aeruginosa identified from clinical specimens at the Department of Clinical Microbiology at the Landspitali University Hospital (LUH) during the time period 1.11.2006 to 31.1.2007. Antibiotic susceptibility testing was performed by disc diffusion tests and all strains were tested for ciprofloxacin susceptibility. Antibiotic resistance data for the last years were collected from the reports of the Department of Clinical Microbiology, but ciprofloxacin susceptibility was usually only tested for specimens from hospitalised patients and when there was resistance to two or more antimicrobial agents. Data on antibiotic use/sales was obtained from the State Epidemiologist at the Directorate of Health., Results: Of the 1861 strains tested, 104 fluoroquinolone resistant strains were identified during the study period, including 91 E. coli (87%), 8 Klebsiella sp. (8%) and 5 P. aeruginosa (5%). No fluoroquinolone resistant Proteus sp. was identified. There was a significant positive correlation between fluoroquinolone use and the frequency of resistant strains of E. coli and Enterobacteriaceae. The frequency of resistant E. coli strains was 6% and it differed significantly between age groups (p >0.001) and sex, 6% for females and 11% for males (p = 0.015). The ratio of fluoroquinolone resistant E. coli was highest in the LUH and homes for the elderly., Conclusion: The frequency of fluoroquinolone resistance is increasing fast in Iceland but is still one of the lowest compared to the other European countries. The frequency is highest in the oldest age groups where the use of the quinolones is the greatest and there was a significant correlation between the quinolone use and the frequency of resistance in E. coli and Enterobacteriaceae. The results highlight the importance of prudent fluoroquinolone use and the need to monitor fluoroquinolone use and resistance.

Background: The diversity in MOMP (major outer membrane protein) of Chlamydia trachomatis is thought to be necessary for the bacteria to survive in its environment. The rate of change in the omp1 gene (coding for MOMP) is not known. Iceland offers a good opportunity to study the epidemiology of chlamydial infections because the population is small (280,000) and geographically well defined., Goal: The goal was to determine the number and distribution of genotypes in a population attending the STD clinic in Reykjavík and to assess changes in omp1 sequences over a period of 2 years., Study Design: Three-hundred thirty isolates of C trachomatis collected periodically from January 1999 to January 2001 were omp1 genotyped with nested PCR and sequencing., Results: The serotypes found, in descending order of prevalence, were E, D, J, F, K, G, H, and I. Eighteen distinctive genotypes were found. During the study period no significant changes in frequency of genotypes were noted, and introduction of new or changed genotypes was not observed., Conclusion: The results indicate a relatively stable situation of genotypes and suggest an ecological advantage of serotype E.

Background: To establish the value of a new technique called transvaginal hydrolaparoscopy for exploration of the tubo-ovarian structures in the management of patients with unexplained infertility., Methods: A total of 120 women with primary or secondary infertility, and without obvious pelvic pathology, were included in the study. The first 14 patients received general anesthesia and underwent transvaginal laparoscopy immediately before standard laparoscopy. The remaining 106 patients had transvaginal laparoscopy performed under local anesthesia, with standard laparoscopy performed only on those with pathology, which required operative intervention. Information on pathology, complications, and successful access to the pouch of Douglas were recorded., Results: The successful rate of access was 93%. Pathology was found in 29 patients, of whom 15 required operative laparoscopy. Also, out of 19 patients with adhesions, 11 (58%) had normal dye test bilateral, and only two (11%) had bilateral occlusion of the tubes. No complications were observed., Conclusion: Transvaginal hydrolaparoscopy is a safe and well-tolerated method for investigating the tubo-ovarian structures in unexplained infertility. It is superior to hysterosalpingography for diagnosis of adhesions.

The purpose of our study was to review all cases of listeriosis in Iceland during the period 1978-2000 and to analyse the genetic relatedness of their isolates. Case records of all patients in Iceland with listeriosis during the period were reviewed and the isolates compared using serotyping and pulsed-field gel electrophoresis (PFGE) using SmaI, AseI and ApaI restriction enzymes. Forty cases of listeriosis were diagnosed during the period, resulting in a mean annual incidence of 6.9 cases per million and a case fatality rate of 33%. In the first 5 y of the study only serotype 4b was observed; subsequently serotypes 1/2a and 1/2b appeared and serotype 4b declined in prevalence. PFGE yielded 24 different genotypes with 7 clusters of indistinguishable genotypes, each comprising 2-6 cases. During 1992-95 the annual incidence of listeriosis in Iceland rose to 15 cases per million. This was largely due to 2 clusters, 1 of 3 cases and the other of 6. No cases of listeriosis were diagnosed during 1998-2000. Our data show an increased number of cases within clusters in the latter half of the period. At the same time, food processing and distribution has become increasingly centralized in Iceland, suggesting an increased risk of listeriosis outbreaks.

Prior to vaccinations against invasive Haemophilus influenzae type b (Hib) diseases in Scandinavia, first initiated in Finland in 1986, the incidence of cases in those five countries was 49/100,000/year in 0- to 4-year-olds and 3.5/100,000 overall. During the following decade, Hib conjugates administered to young children had approximately 95% effectiveness, regardless of which conjugate was used, whether two or three primary doses were administered, and at what age in early infancy the first vaccination was given. The herd immunity effect has extended protection to older age groups. A similar effectiveness of different conjugates in five countries despite considerable diversity in approach suggests that the same impact would occur in other regions with comparable epidemiology. The Scandinavian experience supports the view that three primary vaccine doses are not imperative, thus suggesting that reducing doses of costly Hib vaccines would be one way to facilitate their usage in regions with limited resources.

Background: The prevalence and pattern of Chlamydia trachomatis infection among women requesting induced abortion in the three year period 1992-95 was evaluated and compared to the results of a previous study in 1982-84, where the prevalence of chlamydial infection had been 13.5%., Methods: A total of 1995 women requested termination, 1855 (93%) of whom were tested for Chlamydia and were included in the study. Two types of tests for chlamydial infection, ELISA and PCR, were used in two consecutive periods. In addition cultures for gonorrhea were done in each case. Information on age, marital status, parity, gestational age and the results of chlamydia and gonorrhea tests of the women and sexual partners were recorded., Results: Chlamydia trachomatis positive women were 149 (8.0%), a significant reduction from the previous 1982-84 study (p<0.001). Women with positive tests were significantly younger (80% < or = 25 years of age; p<0.001) and more frequently single (86.6%; p<0.001), than those with negative tests, as in the previous period. Of the partners, 80.4% were contacted, and 52.1% presented for investigation. Of those tested 42.1% were Chlamydia positive. Four women (0.2%) had Neisseria gonorrhea but none of the partners., Conclusions: The prevalence of Chlamydia trachomatis is receding among women coming for termination of pregnancy. As treatment before or at operation has repeatedly been shown to be of benefit and since the prevalence is still considerable, continued screening of these women is justified.

Background: Most clinical overviews of acute bacterial meningitis have either focused on children or all age groups combined, although the disease poses serious problems in the adult population., Objective: To study the clinical and microbiological features of adult bacterial meningitis in Iceland, as a representative of the average European or North American community., Patients and Methods: Data on a total of 132 cases in 127 patients (age, > or = 16 years) who were diagnosed as having acute bacterial meningitis in Iceland during the years 1975 to 1994 were collected from patient and laboratory records. Complete hospital records were found for 119 of the 132 cases identified., Results: The annual incidence was 1.7/100,000 to 7.2/ 100,000 inhabitants (mean, 3.8/100,000). The most common causative organisms were Neisseria meningitidis (56%), Streptococcus pneumoniae (20%), Listeria monocytogenes (6%), and Haemophilus influenzae (5%). Neisseria meningitidis caused 93% of the infections in the 16- to 20-year-old age group, but it caused only 25% of the infections in patients aged 45 years or older. Listeria monocytogenes caused 14% of these cases. Cases of nosocomial and recurrent meningitis were rare. A significant underlying illness or condition was present in 39% of the patients. The mean mortality was 19.7%, and it did not change during the study period., Conclusions: In a study that involved all adult patients with bacterial meningitis in a single country for 2 decades, meningococci and pneumococci were the most frequent causative agents. However, meningococci were responsible for only one fourth of the cases among adult patients aged 45 years or older, most of these cases were caused by pneumococci and Listeria. Despite modern medical developments, approximately 20% of adult patients with bacterial meningitis died.

The five countries of Scandinavia (Denmark, Finland, Iceland, Norway, and Sweden) comprise 22.6 million inhabitants and rather homogeneous socioeconomic conditions. A survey of systemic Haemophilus influenzae diseases over the last decades revealed that the reported incidence of H. influenzae disease is increasing. In recent years, the overall incidence has been 3.5 cases per 100,000 people each year (800 cases annually); in children less than 5 years of age, the annual incidence has been 49 cases per 100,000. Meningitis represents only 52% of all systemic H. influenzae diseases, but lack of reliable data may obscure the importance of other entities. Few strains (less than 5%) are beta-lactamase-positive, and the case fatality rate is 3%. Analysis of seasonal variation shows peaks in June and September-October. If the efficacy of the H. influenzae conjugate vaccines were as high as that of a conjugate vaccine used in Finland during 1986-1987 (approximately 85% efficacy), then at least an 80% reduction in life-threatening H. influenzae infections would be achieved annually by routine immunization before or at the age of 6 months.

The article reports on the number of patients in Iceland who in the last 30 years have been diagnosed as having bacterial meningitis, and on changes in the choice of medication during this period. The vaccination of Icelandic children against Haemophilus Influenzae B began in 1989.

Examination of the trends of meningococcal infection in Norway, Iceland, Faroe Islands, Denmark, England and Wales, and the Netherlands, has shown that Neisseria meningitidis B:2b:P1.2 and/or B:2a:P1.2 phenotypes were associated with peaks of infection in the Netherlands in 1966, in Iceland 1976-77, and in England and Wales in 1973-75. These strains were present in all six countries in the decade 1970-80 but their prevalence is now practically negligible. In contrast the prevalence of the B:15:P1.16 phenotype has risen. In the Faroe Islands and northern Norway this change in serotype prevalence has been followed by rises in incidence of meningococcal disease; the same is happening in England and Wales but not yet in the other countries.

Scandinavia (Denmark, Finland, Iceland, Norway, and Sweden) comprises with mutual borders and 22.3 million inhabitants an area where the socioeconomic and cultural conditions are similar. Epidemic diseases, such as meningococcal infection, might therefore be expected to be uniformly distributed. An epidemiological study in the 10-year period 1970-9 shows, however, remarkable differences in the incidence, age, and serogroup and type distribution, as well as in the general dynamics of the disease. Three epidemics, two caused by different serotypes of group B (Norway and Iceland) and one by group A (Finland) occurred within the observation period. The annual overall incidence was generally around 3/100 000 but increased from fivefold (Finland) to eightfold (northern Norway) during epidemics. The epidemic strains caused infection in over 3000 patients and the loss of at least 250 lives. The overall case fatality rate was 8.6% (range 4.1-13.7%). Men were more susceptible and had a worse prognosis than women of the same age group. The group A epidemic in Finland was influenced by a large vaccination campaign, but this possibility was not feasible in the two other epidemics.