Influenza hospitalizations during childhood in children born preterm

Objective: The objective is to determine if children born preterm were at increased risk of influenza hospitalization up to age five. Methods: National registry data on all children born in Norway between 2008 and 2011 were used in Cox regression models to estimate adjusted hazard ratios (aHRs) for influenza hospitalizations up to age five in children born preterm (<37 pregnancy weeks). HRs were also estimated separately for very preterm (<32 weeks), early term (37-38 weeks), and post-term (≥42 weeks) children. Results: Among 238,628 children born in Norway from January 2008 to December 2011, 15,086 (6.3%) were born preterm. There were 754 (0.3%) children hospitalized with influenza before age five. The rate of hospitalizations in children born preterm was 13.8 per 10,000 person-years (95% confidence interval [CI] [11.3, 16.7]), and 5.9 per 10,000 person-years (95% CI [5.5, 6.4]) in children born at term (≥37 weeks). Children born preterm had a higher risk of influenza hospitalization before age 5: aHR 2.33 (95% CI [1.85, 2.93]). The risk increased with decreasing gestational age and was highest among those born extremely/very preterm; aHR 4.07 (95% CI [2.63, 6.31]). Compared with children born at 40-41 weeks, children born early term also had an elevated risk of influenza hospitalization; aHR (37 weeks) 1.89 (95% CI [1.43, 2.50]), aHR (38 weeks) 1.43 (95% CI [1.15, 1.78]). Conclusion: Children born preterm had a higher risk of influenza hospitalizations before age five. An elevated risk was also present among children born at an early term. Children born preterm could benefit from influenza vaccinations

Sales of oseltamivir in Norway prior to the emergence of oseltamivir resistant influenza A(H1N1) viruses in 2007–08

<p>Abstract</p> <p>Background</p> <p>An unprecedented high proportion of oseltamivir resistant influenza A(H1N1) viruses emerged in the 2007–08 influenza season. In Norway, two thirds of all tested A(H1N1) viruses were resistant to the antiviral drug. In order to see if this emergence could be explained by a drug induced selection pressure, we analysed data on the sales of oseltamivir in Norway for the years 2002–07.</p> <p>Methods</p> <p>We used data from two sources; the Norwegian Drug Wholesales Statistics Database and the Norwegian Prescription Database (NorPD), for the years 2002–2007. We calculated courses sold of oseltamivir (Tamiflu^®) per 1000 inhabitants per year.</p> <p>Results</p> <p>Our data showed that, except for the years 2005 and 2006, sales of oseltamivir were low in Norway; courses sold per 1000 inhabitants varied between 0.17–1.64. The higher sales in 2005 and 2006 we believe were caused by private stockpiling in fear of a pandemic, and do not represent actual usage.</p> <p>Conclusion</p> <p>A drug induced selection pressure was probably not the cause of the emergence of oseltamivir resistant influenza A(H1N1) viruses in 2007–08 in Norway.</p

Oseltamivir-Resistant Influenza Viruses A (H1N1), Norway, 2007–08

Resistance was not associated with oseltamivir use or more severe disease

Evaluation of the national surveillance system for point-prevalence of healthcare-associated infections in hospitals and in long-term care facilities for elderly in Norway, 2002-2008

<p>Abstract</p> <p>Background</p> <p>Since 2002, the Norwegian Institute of Public Health has invited all hospitals and long-term care facilities for elderly (LTCFs) to participate in two annual point-prevalence surveys covering the most frequent types of healthcare-associated infections (HAIs). In a comprehensive evaluation we assessed how well the system operates to meet its objectives.</p> <p>Methods</p> <p>Surveillance protocols and the national database were reviewed. Data managers at national level, infection control practitioners and ward personnel in hospitals as well as contact persons in LTCFs involved in prevalence data collection were surveyed.</p> <p>Results</p> <p>The evaluation showed that the system was structurally simple, flexible and accepted by the key partners. On average 87% of hospitals and 32% of LTCFs participated in 2004-2008; high level of data completeness was achieved. The data collected described trends in the prevalence of reportable HAIs in Norway and informed policy makers. Local results were used in hospitals to implement targeted infection control measures and to argue for more resources to a greater extent than in LTCFs. Both the use of simplified Centers for Disease Control and Prevention (CDC) definitions and validity of data seemed problematic as compliance with the standard methodology were reportedly low.</p> <p>Conclusions</p> <p>The surveillance system provides important information on selected HAIs in Norway. The system is overall functional and well-established in hospitals, however, requires active promotion in LTCFs. Validity of data needs to be controlled in the participating institutions before reporting to the national level.</p

Risk conditions in children hospitalized with influenza in Norway, 2017–2019

Background Norwegian children are more frequently hospitalized with influenza than adults. Little is known about the characteristics of these children. Our aim was to investigate the presence of pre-existing risk conditions and to determine the duration of influenza hospitalizations in children during two influenza seasons. Methods The Norwegian Patient Registry holds data on all hospitalized patients in Norway. We included all patients younger than 18 years hospitalized with a diagnosis of influenza during the influenza seasons 2017–18 and 2018–19. Pre-existing risk conditions for influenza were identified by ICD-10 diagnoses in the Norwegian Patient Registry. In addition, information on asthma diagnoses were also retrieved from the Norwegian Registry for Primary Health Care. To estimate the prevalence of risk conditions in the child population, we obtained diagnoses on all Norwegian children in a two-year period prior to each influenza season. We calculated age-specific rates for hospitalization and risk for being hospitalized with influenza in children with risk conditions. Results In total, 1013 children were hospitalized with influenza during the two influenza seasons. Children younger than 6 months had the highest rate of hospitalization, accounting for 13.5% of all admissions (137 children). Hospitalization rates decreased with increasing age. Among children hospitalized with influenza, 25% had one or more pre-existing risk conditions for severe influenza, compared to 5% in the general population under 18 years. Having one or more risk conditions significantly increased the risk of hospitalization, (Odds Ratio (OR) 6.1, 95% confidence interval (CI) 5.0–7.4 in the 2017–18 season, and OR 6.8, 95% CI 5.4–8.4 in the 2018–19 season). Immunocompromised children and children with epilepsy had the highest risk of hospitalization with influenza, followed by children with heart disease and lung disease. The average length of stay in hospital were 4.6 days, and this did not differ with age. Conclusion Children with pre-existing risk conditions for influenza had a higher risk of hospitalization for influenza. However, most children (75%) admitted to hospital with influenza in Norway during 2017–2019 did not have pre-existing risk conditions. Influenza vaccination should be promoted in particular for children with risk conditions and pregnant women to protect new-borns

Human to animal transmission of influenza A(H1N1)pdm09 in a turkey breeder flock in Norway

Introduction: Routine surveillance samples disclosed seropositivity to influenza A virus (IAV) in a Norwegian turkey breeder flock. Simultaneous reports of influenza-like symptoms in farm workers and a laboratory confirmed influenza A(H1N1)pdm09 (H1N1pdm09) infection in one person led to the suspicion of a H1N1pdm09 infection in the turkeys. Animals and methods: H1N1pdm09 infection was confirmed by a positive haemaggutinin inhibition test using H1N1pdm09 antigens, and detection of H1N1pdm09 nucleic acid in reproductive organs of turkey hens. The flock showed no clinical signs except for a temporary drop in egg production. Previous reports of H1N1pdm09 infection in turkeys suggested human-to-turkey transmission (anthroponosis) during artificial insemination. Results and discussion: The flock remained seropositive to IAV and the homologous H1N1pdm09 antigen throughout the following 106 days, with decreasing seroprevalence over time. IAV was not detected in fertilised eggs or in turkey poults from the farm, however, maternally derived antibodies against H1N1pdm09 were found in egg yolks and in day-old poults. Genetic analyses of haemagglutinin gene sequences from one of the infected farm workers and turkeys revealed a close phylogenetic relationship, and confirmed human-to-turkey virus transmission