RESUMEN
Two distinct genetic clades of seasonal influenza A(H1N1) viruses have cocirculated in the recent seasons: clade 2B oseltamivir-resistant and adamantane-susceptible viruses, and clade 2C viruses that are resistant to adamantanes and susceptible to oseltamivir. We tested seasonal influenza A(H1N1) viruses collected in 2008-2010 from the United States and globally for resistance to antivirals approved by the Food and Drug Administration. We report 28 viruses with both adamantane and oseltamivir (dual) resistance from 5 countries belonging to 4 distinct genotypes. Because of limited options for antiviral treatment, emergence of dual-resistant influenza viruses poses a public health concern, and their circulation needs to be closely monitored.
Asunto(s)
Adamantano/farmacología , Antivirales/farmacología , Farmacorresistencia Viral Múltiple , Subtipo H1N1 del Virus de la Influenza A/efectos de los fármacos , Gripe Humana/epidemiología , Gripe Humana/virología , Oseltamivir/farmacología , Sustitución de Aminoácidos/genética , Genoma Viral , Genotipo , Humanos , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Mutación Missense , Neuraminidasa/genética , ARN Viral/genética , Proteínas de la Matriz Viral/genética , Proteínas Virales/genéticaRESUMEN
Given the potential worsening clinical severity of 2009 pandemic influenza A (H1N1) virus (pH1N1) infection from spring to fall 2009, we conducted a clinical case series among patients hospitalized with pH1N1 infection from September through October 2009. A case patient was defined as a hospitalized person who had test results positive for pH1N1 virus by real-time reverse-transcription polymerase chain reaction. Among 255 hospitalized patients, 34% were admitted to an intensive care unit and 8% died. Thirty-four percent of patients were children <18 years of age, 8% were adults ≥ 65 years of age, and 67% had an underlying medical condition. Chest radiographs obtained at hospital admission that had findings that were consistent with pneumonia were noted in 103 (46%) of 255 patients. Among 255 hospitalized patients, 208 (82%) received neuraminidase inhibitors, but only 47% had treatment started ≤ 2 days after illness onset. Overall, characteristics of hospitalized patients with pH1N1 infection in fall 2009 were similar to characteristics of patients hospitalized with pH1N1 infection in spring 2009, which suggests that clinical severity did not change substantially over this period.
Asunto(s)
Hospitalización/estadística & datos numéricos , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Humana/epidemiología , Gripe Humana/virología , Pandemias , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Antivirales/administración & dosificación , Niño , Preescolar , Cuidados Críticos/normas , Femenino , Humanos , Lactante , Recién Nacido , Gripe Humana/mortalidad , Gripe Humana/patología , Pulmón/patología , Masculino , Persona de Mediana Edad , Neumonía Viral/patología , Radiografía Torácica , Estados Unidos/epidemiología , Adulto JovenRESUMEN
During the spring of 2009, pandemic influenza A (H1N1) virus (pH1N1) was recognized and rapidly spread worldwide. To describe the geographic distribution and patient characteristics of pH1N1-associated deaths in the United States, the Centers for Disease Control and Prevention requested information from health departments on all laboratory-confirmed pH1N1 deaths reported from 17 April through 23 July 2009. Data were collected using medical charts, medical examiner reports, and death certificates. A total of 377 pH1N1-associated deaths were identified, for a mortality rate of .12 deaths per 100,000 population. Activity was geographically localized, with the highest mortality rates in Hawaii, New York, and Utah. Seventy-six percent of deaths occurred in persons aged 18-65 years, and 9% occurred in persons aged ≥ 65 years. Underlying medical conditions were reported for 78% of deaths: chronic lung disease among adults (39%) and neurologic disease among children (54%). Overall mortality associated with pH1N1 was low; however, the majority of deaths occurred in persons aged <65 years with underlying medical conditions.