A new pandemic influenza A(H1N1) genetic variant predominated in the winter 2010 influenza season in Australia, New Zealand and Singapore

Abstract

Pandemic H1N1 influenza virus is of global health concern and is currently the predominant influenza virus subtype circulating in the southern hemisphere 2010 winter. The virus has changed little since it emerged in 2009, however, in this report we describe several genetically distinct changes in the pandemic H1N1 influenza virus. These variants were first detected in Singapore in early 2010 and have subsequently spread through Australia and New Zealand. At this stage, these signature changes in the haemagglutinin and neuraminidase proteins have not resulted in significant antigenic changes which might make the current vaccine less effective, but such adaptive mutations should be carefully monitored as the northern hemisphere approaches its winter influenza season.

Monitoring Genetic Diversity of Influenza A(H1N1)pdm09 Virus Circulating during the Post-Pandemic Period in Turkey

“…However, there is currently no report regarding the significance of these alterations. The genetic group i, characterized by the N125D substitution located in the E antigenic region (22,23), was identified during the winter of 2010 in the Southern Hemisphere (24) and between March and December 2010 in Hong Kong (25) and the United Kingdom (UK) (26). However, this mutation was not detected in the viral isolates collected in Turkey during this study period.…”

Addition of Glycosylation to Influenza A Virus Hemagglutinin Modulates Antibody-Mediated Recognition of H1N1 2009 Pandemic Viruses

“…During 2010, HA variants expressing N125D and E374K were associated with several vaccine breakthroughs and a number of fatal cases (68,69), yet they could not be distinguished antigenically from Cal/09. However, A(H1N1)pdm viruses circulating in Finland (2009-2010 and 2010-2011) with N125D and/or N156K were less sensitive to neutralization by sera from individuals that were vaccinated or infected with Cal/09-like viruses (70).…”

Identification of Critical Residues in the Hemagglutinin and Neuraminidase of Influenza Virus H1N1pdm for Vaccine Virus Replication in Embryonated Chicken Eggs

“…A/Brisbane/10/2010-like viruses having an H1 HA N125D change were initially detected in late April 2010 in clinical isolates from the Southern Hemisphere. Although these newer strains did not have major antigenicity changes compared to the CA/09 strain, they have been reported to be associated with several vaccine breakthrough infections and were identified in a number of fatal cases (21,22). The 127 and 209 changes in A/New Hampshire/2/2010 HA resulted from egg adaptation (7,23).…”