Burden of Rotavirus Disease in Norway: Using National Registries for Public Health Research.

BACKGROUND: Norway introduced routine rotavirus immunization for all children born on or after September 1, 2014. We estimated the healthcare burden of all-cause gastroenteritis and rotavirus disease in children <5 years old to establish the prevaccine baseline and support the ongoing immunization program. METHODS: We examined national registry data on gastroenteritis-associated primary care consultations and hospitalizations for 2009-2013 and data on all deaths in children <5 years old reported during 2000-2013. We also established rotavirus hospital surveillance from February 2014 through January 2015. RESULTS: Before vaccine introduction, 114.5 cases per 1000 children <5 years old were treated in primary care and 11.8 children per 1000 were hospitalized with gastroenteritis annually. During hospital surveillance, rotavirus was detected in 65% (95% confidence interval: 60-70) of inpatient gastroenteritis cases. We estimated that 4.0 inpatient and 2.3 outpatient cases per 1000 children were seen in hospital with rotavirus disease annually, suggesting that 1 in 32 children was hospitalized by age 5. Additional 30.6 rotavirus cases per 1000 children consulted primary care annually or 1 in every 7 children by the age of 5 years. Rotavirus-associated mortality was estimated at 0.17 deaths per 100,000 children <5 years old, corresponding to 1 death every second year. CONCLUSIONS: Rotavirus remains the primary cause of severe gastroenteritis in children in Norway. The unique population-based registers, in combination with an established rotavirus surveillance platform, provide a well-suited setting to evaluate the impact of rotavirus vaccination.

Rotavirus gastroenteritis in Norway: analysis of prospective surveillance and hospital registry data.

We aimed to evaluate rotavirus morbidity and describe rotavirus epidemiology in hospitalized children in Norway to provide information before the introduction of new rotavirus vaccines. We retrospectively reviewed 14,973 gastroenteritis hospitalizations in children aged <5 y for the period 1995 to 2004, and prospectively surveyed for rotavirus in 311 children aged <5 y admitted with diarrhoea to 3 hospitals in 2006-2008. The proportion of rotavirus among all gastroenteritis hospitalizations was estimated at 14.5% from the retrospective data and at 62.9% in the prospective data. The annual incidence of rotavirus hospitalizations is estimated to be 3 per 1000 children <5 y of age, corresponding to approximately 900 (range 735-1092) hospitalizations each year. Children aged 6-23 months accounted for 61% of all confirmed rotavirus cases, and average duration of hospital stay for rotavirus cases was 1.3 days. We observed a predominance of rotavirus infections from March through May, similar to the seasonality of diarrhoea-associated hospitalizations with viral and unspecified aetiology. No rotavirus-associated deaths were reported. It is estimated that two thirds of all gastroenteritis hospitalizations in children <5 y of age may be attributable to rotavirus in Norway. Continued surveillance and further studies are needed to assess the full burden of rotavirus disease and its economic impact in Norway.

Detection and characterization of group A rotaviruses in children hospitalized with acute gastroenteritis in Norway, 2006-2008.

To assess the genetic diversity of rotavirus strains in Norway, the distribution of rotavirus genotypes was studied in children admitted to hospital with acute gastroenteritis. The detection of rotavirus in stool samples was compared using an enzyme-linked immunosorbent assay (ELISA), an immunochromatographic test and RT-PCR. Children <5 years of age admitted to hospital with diarrhea in three large hospitals were enrolled prospectively from March 2006 to February 2008. Rotavirus was detected in 58% of the children by the immunochromatographic test, in 63% by ELISA and 72% by RT-PCR. A total of 219 (70%) rotavirus isolates were characterized in order to determine the genotype. The predominant G types included G1 (53%), G9 (16%), and G3 (13%), and the frequency of G3 varied more than G9 between seasons (8-20%). The P[8] genotype was identified in 188 (86%) of samples, and the globally common genotype combinations G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8] accounted together for >80% of infection. No unusual rotavirus strains were detected, and only four samples contained mixed infections. This study demonstrates that ELISA has similar specificity but lower sensitivity compared to RT-PCR. The immunochromatographic test had the lowest sensitivity and specificity compared to the other assays. Rotaviruses causing severe gastroenteritis leading to hospitalization of children <5 years of age in Norway include the common genotypes, however, a considerable geographical and seasonal variation was observed in the distribution of these genotypes. These data may be important for assessing the need for introducing rotavirus vaccines into immunization programs in Norway.

Incidence and risk factors for genital Chlamydia trachomatis infection: a 4-year prospective cohort study.

BACKGROUND: Few long-term studies reporting incidence and behavioral data for Chlamydia trachomatis (CT) infection in the general population have been published. Such studies are important to understand risk factors associated with infection and to develop screening recommendations. METHODS: A fixed prospective 4-year cohort study of 898 sexually active Norwegian women, aged 16 to 23 years at study start, was conducted to assess incidence, repeat infection, and risk factors associated with genital CT infection. Participants were interviewed at study start and at 6-month intervals thereafter for behavioral characteristics. The women were tested for CT infection at 12-month intervals beginning at study start. Risk factors were assessed using Fisher exact test and conditional logistic regression. Person-time was estimated in survival analyses and incidence of CT infection was reported as events per 100 woman-years. RESULTS: Median duration of observation was 48.0 months (range 10-74) whereas 4.4 specimens were collected per woman (range 2-5). Of the 836 women eligible for the analysis, 19 (2.2%) had a prevalent infection at baseline. The 4-year cumulative incidence of CT infection was 7.7 (95% CI: 6.7-8.7) with annual incidences ranging from 1.2 to 2.9 per 100 woman-years. The 2-year cumulative incidence of repeat CT infection was 11.2 (95% CI: 9.3-13.1) per 100 woman-years. In multivariate analyses, factors associated with incident CT infection were young age (< or =24 years) and number of new partners over the last 12 months prior being tested. CONCLUSION: The annual incidences observed for women 24 years or younger with 1 or more new partners over the last 12 months support recommendations for annual testing for CT in this age group in Norway.

A new automated method for isolation of Chlamydia trachomatis from urine eliminates inhibition and increases robustness for NAAT systems.

Chlamydia trachomatis is a leading cause of sexually transmitted infection. Diagnostic methods with easy non-invasive sample collection are important to increase testing and hence to reduce the spread of this infection. To enable more use of urine samples in C. trachomatis diagnostics, automation is an absolute requirement since obtaining high-quality DNA from urine specimens involves extensive processing. Here, we present a study in which a new automated sample preparation method, BUGS'n BEADS STI (BnB STI), was used up-front of the BDProbeTec ET end point analysis and compared with the full BDProbeTec ET method to analyze C. trachomatis in 1002 urine samples. The BnB STI system represents a new concept within magnetic sample preparation in which bacteria are first isolated from the sample material followed by purification of bacterial nucleic acid using the same magnetic particles. Similar sensitivity and specificity were obtained with both methods. None of the samples processed with BnB STI inhibited the BDProbeTec ET test whereas 1.8% showed inhibition when processed according to the manual BDProbeTect ET DNA preparation method. Moreover, the average MOTA scores obtained with the BnB STI system were 48% higher for all amplification controls and 57% higher for positive samples, compared to the manual sample preparation. Based on these results and the significant reduction in hands-on-time for urine sample processing, the automated BnB STI sample preparation method was implemented for routine analysis of C. trachomatis from urine samples.

Chlamydia trachomatis among young Norwegian men: sexual behavior and genitourinary symptoms.

OBJECTIVE: The study objective was to assess Chlamydia trachomatis (CT) prevalence, risk factors, and genitourinary symptoms among young men. METHODS: Sexually active men 18 to 30 years old were recruited during April through October 2005 at the student health services and through field work at university campuses in 2 Norwegian cities. A total of 1,032 participants completed a questionnaire on sexual behavior and provided first-void urine for CT testing. RESULTS: The overall CT prevalence was 7.8% (81 of 1,032). In multivariable analysis, >or=5 lifetime sexual partners (adjusted odds ratio [aOR]: 2.7, 95% confidence interval [CI]: 1.4-5.2), a burning sensation on urination (aOR: 5.7, 95% CI: 3.1-10.5), and penile discharge (aOR: 2.6, 95% CI: 1.1-6.3) were significant risk factors for a positive CT test, whereas condom use (last intercourse) was preventive (aOR: 0.4, 95% CI: 0.2-0.8). CONCLUSIONS: A CT prevalence of 7.8% was found among male students. Promotion of increased testing among men is important to prevent CT transmission.

[Prevalence of genital Chlamydia trachomatis infection in the age group 18-29 years in Oslo]. / Forekomst av genital infeksjon med Chlamydia trachomatis blant 18-29-åringer i Oslo.

BACKGROUND: Earlier Norwegian prevalence studies of genital C. trachomatis infection have mainly been carried out among women and in selected patient groups. We decided to do a population-based prevalence study among young men and women in Oslo. The study was done within the framework of the new Norwegian list patient system, in which each citizen is assigned to one particular doctor. METHODS: Cross-sectional study. All patients 18-29 years old listed with a group practice in Oslo received a personal letter of invitation. We asked each person to submit a urine sample and fill in a questionnaire. The urinary samples were tested by means of a DNA amplification method. Non-respondents received one reminder. RESULTS: 685 persons were invited to participate, 234 responded (36%); 169 females (43%) and 65 males (25%). A total of 6 respondents (3%, 95% CI 1.2-5.5) tested positively, 4 of them were males. At least 51% of the females and 25% of the males had previously been examined for C. trachomatis, and at least 18% of the females and 8% of the males had received treatment. A total of 70% stated that they would see their doctor if they suspected a genital chlamydial infection. INTERPRETATION: Opportunistic testing for C. trachomatis infection should be offered more frequently to young men. A national prevalence study of genital chlamydial infection should be carried out. The new list patient system offers new opportunities for research in primary medical care in Norway.

Reliability of the Amplicor internal control to disclose false-negative Chlamydia trachomatis PCR results.

Four possibly false-negative samples were detected when 514 male urine specimens were tested in the Amplicor Chlamydia trachomatis assay. In three of the four samples, the inhibition could be reduced by removal of urine supernatant. Under partially inhibitory conditions, after spiking with 50 C. trachomatis elementary bodies/ml specimen, a selective inhibition of the C. trachomatis target amplification and a preferential internal control amplification was observed. We conclude that a positive internal control signal might be misleading in inhibitory specimens with low amount of C. trachomatis.

[Chlamydia infections and sexual behavior among young women]. / Chlamydiainfeksjon og seksualatferd blant unge kvinner.

BACKGROUND: We wanted to determine the prevalence of Chlamydia trachomatis in a sample of young women and to assess risk factors related to sexual behaviour that are predictive of such infection. MATERIAL AND METHODS: 898 healthy, non-pregnant women aged 16 to 24 years attending primary care centres over a two-year period (September 1998 to December 2000) were recruited for the study. Uterine cervix samples were tested for Chlamydia trachomatis and participants were interviewed about their sexual behaviour. Chlamydia test results from 881 samples were valid. RESULTS: The prevalence of genital Chlamydia trachomatis infection was 2.4% (21/881). In univariable analyses, a high number of lifetime partners (four or more), smoking, previous pregnancy and a previous positive chlamydia test were factors predictive of a positive Chlamydia test. In multivariable analyses, previous pregnancy and a previous positive Chlamydia test were the only significant factors. The number of lifetime partners was higher among women who had been pregnant or previously had tested positively for Chlamydia. INTERPRETATION: The prevalence of Chlamydia was low in this population. Risk behaviour (frequent change of partners) can be expressed by teenage pregnancy and positive Chlamydia test results and these factors can be used for identification of women who should be tested more frequently than others for Chlamydia infection in a low-prevalence population.