After a 10-day course of oral oseltamivir for pandemic (H1N1) 2009 influenza infection, a renal transplant recipient developed rapid-onset severe primary viral pneumonia due to oseltamivir-resistant virus. Respiratory failure progressed despite high-dose oral oseltamivir, nebulised zanamivir and cessation of immunosuppressive medications, but his condition improved with intravenous zanamivir. H...

To the Editor: During the spring of 2009, a pandemic influenza A (H1N1) virus emerged and spread globally. Initial testing of the virus found it susceptible to neuraminidase inhibitors and resistant to adamantanes (1,2). As of March 5, 2010, only 264 cases of oseltamivir-resistant pandemic (H1N1) 2009 infection had been reported to the World Health Organization, but the number of cases has been...

Oseltamivir (Tamiflu) is currently the frontline antiviral drug employed to fight the flu virus in infected individuals by inhibiting neuraminidase, a flu protein responsible for the release of newly synthesized virions. However, oseltamivir resistance has become a critical problem due to rapid mutation of the flu virus. Unfortunately, how mutations actually confer drug resistance is not well u...

Neuraminidase (NA) mutations responsible for influenza resistance to oseltamivir vary according to the NA subtype; in influenza A/H3N2 viruses, NA-gene mutations occur predominantly at codons E119 and R292. In an oseltamivir-resistant influenza A/H3N2 virus isolated from an immunocompromised child after 107 days of cumulative treatment, the NA gene contained 3 aa substitutions (N146K, S219T, an...

Oseltamivir is the most common antiviral drug used to treat and prevent influenza. Epidemiological studies performed in Japan, the United States, and the United Kingdom indicate that oseltamivir may cause psychiatric symptoms; however, the underlying mechanism has not been elucidated. In South Korea, interest in oseltamivir has increased with the spread of the new influenza virus; however, no c...

It has been suggested that oseltamivir-resistant influenza viruses harboring the H274/275Y mutation are less virulent than are those that are oseltamivir-sensitive, and fatality attributed to infection with an oseltamivir-resistant virus is very rare. Here we report the first fatal adult case of oseltamivir-resistant 2009 pandemic influenza A (H1N1) in Korea. A 60-year-old Korean male who had h...

BACKGROUND Influenza causes lower respiratory tract complications (LRTCs), particularly bronchitis and pneumonia, in both otherwise healthy adults and those with underlying conditions. The aim of this study was to assess the effect of oseltamivir treatment on the incidence of LRTCs leading to antibiotic treatment and hospitalizations following influenza illness. METHODS We analyzed prospectiv...

A recent in vitro study showed that the three compounds of antiviral drugs with different mechanisms of action (amantadine, ribavirin, and oseltamivir) could result in synergistic antiviral activity against influenza virus. However, no clinical studies have evaluated the efficacy and safety of combination antiviral therapy in patients with severe influenza illness. A total of 245 adult patients...

OBJECTIVES It was the aim of this study to examine the influence of the antiviral medication oseltamivir on stroke and transient ischemic attack (TIA) in adults diagnosed with influenza. METHODS This retrospective cohort study used medical and pharmaceutical claims data from May 2000 to September 2006 from an administrative claims database. Episodes of stroke/TIA in the 6 months after influen...

Oseltamivir has been widely used for pandemic (H1N1) 2009 virus infection, and by April 30, 2010, a total of 285 resistant cases were reported worldwide, including 45 in the United Kingdom. To determine risk factors for emergence of oseltamivir resistance and severe infection, a case-control study was conducted in the United Kingdom. Study participants were hospitalized in England or Scotland d...