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Abstract Background 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. Methods 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. Results 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. Conclusion 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.

The first influenza pandemic of the 21st century was caused by novel H1N1 viruses that emerged in early 2009. Molecular evolutionary analyses of the 2009 pandemic influenza A H1N1 [A(H1N1)pdm09] virus revealed two major clusters, cluster I and cluster II. Although the pathogenicity of viruses belonging to cluster I, which became extinct by the end of 2009, has been examined in a nonhuman primate model, the pathogenic potential of viruses belonging to cluster II, which has spread more widely in the world, has not been studied in this animal model. Here, we characterized two Norwegian isolates belonging to cluster II, namely, A/Norway/3568/2009 (Norway3568) and A/Norway/3487-2/2009 (Norway3487), which caused distinct clinical symptoms, despite their genetic similarity. We observed more efficient replication in cultured cells and delayed virus clearance from ferret respiratory organs for Norway3487 virus, which was isolated from a severe case, compared with the efficiency of replication and time of clearance of Norway3568 virus, which was isolated from a mild case. Moreover, Norway3487 virus to some extent caused more severe lung damage in nonhuman primates than did Norway3568 virus. Our data suggest that the distinct replicative and pathogenic potentials of these two viruses may result from differences in their biological properties (e.g., the receptor-binding specificity of hemagglutinin and viral polymerase activity). [ABSTRACT FROM AUTHOR]

Background: At its discovery in 1981, AIDS was a fatal syndrome that rapidly led to death. Combination treatment with at least three drugs has radically improved the prognosis., Material and Methods: The study includes all HIV-patients controlled at the Department of Infectious Diseases, Ullevål University Hospital from 1982 to 2005. Development of immune deficiency, morbidity and causes of death were registered prospectively. Possible connections between death and HIV-infection and treatment were evaluated., Results: 1632 patients were followed at our department. 32 % of these patients have died. The number of patients who died annually during the 5 years from 1986 to 1990 was 47 % and this was reduced to 11 % in 2001 - 05. Many patients still die because they either present too late for treatment or have received insufficient treatment. 22 patients have died during the last 10 years irrespective of starting treatment with at least 3 antiretroviral drugs: 7 died from cancers, 6 from treatment failure, one from unknown cause and 8 from other causes. The 6 patients who died from treatment failure had very low CD4 counts and serious opportunistic infections that could not be treated effectively at the time of diagnosis., Interpretation: Patients who start and adhere to treatment with 3 HIV-medications have a good prognosis, but they may still have an increased risk of non-AIDS defining cancers and cardiovascular disease. HIV/AIDS has become a chronic disease with a good prognosis.