Pandemic H1N1 influenza infections in 2009

Abstract

In early spring 2009 an outbreak of H1N1 influenza A virus infection was detected in Mexico, spreaded quickly, and on June 11 2009, World Health Organization raised its pandemic level to phase 6. This novel H1N1 pandemic influenza A virus represented a quadruple reassortment of swine, human and avian influenza virus strains. This pandemic 2009 H1N1 influenza A viruses in different regions of the world were found to be antigenically homogenous. Transmission features, incubation period and clinical findings wee similar with the seasonal influenza viruses, although the gastrointestinal manifestations were more common. Young children (< 5years) and some special risk groups are at increased risk for infection complications and mortality. The recommended test for diagnosis is real-time PCR. Pandemic 2009 H1N1 influenza A strains are sensitive to neuraminidase inhibitors (oseltamivir, zanamivir) and resistant to amantadine and rimantadine. Oseltamivir and zanamivir are used for prophlaxis and therapy of infection. However, vaccination against pandemic 2009 H1N1 influenza A should be the main target for individual and population based prevention. Monovalent pandemic 2009 H1N1 influenza A vaccines are available in this (recent) influenza season. According to CDC, the next (2010-2011) influenza season trivalent vaccines will coverage the pandemic 2009 H1N1 influenza A vaccine.