The end of the pandemic - what will be the pattern of influenza in the 2010-11 European winter and beyond?

Editorials The end of the pandemic – what will be the pattern of influenza in the 2010-11 European winter and beyond? that the world has moved into the post-pandemic period [1]. Following the advice of the Emergency Committee, which based its assessment on the global situation, WHO declared that there has been a pandemic phase change and that the WHO post-pandemic definition, 'Levels of influenza activity have returned to the levels seen for inter-pandemic influenza in most countries with adequate surveillance', has been met [2]. In order to come to this conclusion it has been important to observe the pattern of influenza in the southern hemisphere temperate countries which are now experiencing their winter. What does this mean for the 2010-11 winter in Europe and winters beyond? Current influenza activity in the southern hemisphere temperate countries In their 2010 winter, the five southern hemisphere countries with ongoing surveillance (Argentina, Australia, Chile, New Zealand and South Africa) have experienced levels of influenza-like illness (ILI) or acute respiratory infection (ARI) that are considerably lower than those of the 2009 winter. In these countries the level of illness is looking more like inter-pandemic influenza than the pandemic levels seen in the winter of 2009 [3,4], as documented in a special issue by Eurosurveillance [5]. In 2010 in Chile there have been more cases of acute ARI in children but this is attributable to epidemics of respiratory syncytial virus infections (RSV) rather than influenza [3]. This emphasises the importance of countries being able to test for a suite of respiratory pathogens , not just influenza. In the equatorial countries, the combined epidemiological and virological surveillance needed for routine influenza surveillance was uncommon until the 2009 pandemic. Hence whether what is being seen in 2010 is normal for inter-pandemic influenza is unclear as there are simply no baseline data in many countries. However, in the locations that have consistently delivered good quality surveillance data for a wide range of respiratory pathogens, such as Singapore and southern China, the epidemics of 2010 have shown levels that are more similar to those of 2008 and not that of the 2009 pandemic [4]. Virologically the 2010 southern hemisphere winter epidemics have been mixed: New Zealand has been dominated by pandemic A(H1N1) viruses while Australia, Argentina and Chile have seen more of a mix of the pandemic A(H1N1), A(H3N2) and some B viruses [3,4]. Exceptional among the five, South …