The WHO Consultation on the Composition of Influenza Vaccines for the Southern Hemisphere 2012 was held in Geneva on 26-28 September 2011. Following the Consultation, WHO made the following recommendation:

It is recommended that vaccines for use in the 2012 influenza season (southern hemisphere) contain the following:

• an A/California/7/2009 (H1N1)-like virus;
• an A/Perth/16/2009 (H3N2)-like virus;
• a B/Brisbane/60/2008-like virus.

This is the same recommendation as the vaccine composition for the northern hemisphere 2011-2012, indicating that the circulating viruses have not undergone significant antigenic drift since the last Consultation in February 2011.

The Australian and New Zealand annual seasonal influenza immunisation programmes have now commenced for 2011. More information on the seasonal influenza vaccine and people in particular risk groups for whom the vaccine is free can be found at the following websites:

Australian Government Department of Health and Ageing: Immunise Australia Program
New Zealand Government Ministry of Health: Influenza 2011

The past month has seen high levels of influenza activity in the northern hemisphere as the winter continues. In contrast, transmission levels remain low in the southern hemisphere. Updates on global influenza activity are available on the WHO Global Alert and Response webpage.

In the period 1 January-21 March, 2011, the WHO Collaborating Centre for Influenza in Melbourne has identified the type and subtype of 311 influenza samples by antigenic and/or genetic analysis. Of these samples, 215 are from Australia with the following distribution across states and territories:

Type/Subtype	ACT	NSW	NT	QLD	SA	TAS	VIC	WA	Total
A(H1N1)pdm09	0	1	16	62	0	1	12	0	92
A(H3N2)	0	1	15	53	0	1	3	0	73
B	0	0	31	16	0	2	18	0	50
Total	0	2	62	131	0	2	18	0	215

See our surveillance data map to view the distribution of influenza viruses in different countries during 2010.

The fifth WHO Collaborating Centre for Reference and Research on Influenza was recently launched at the Chinese National Influenza Center in Beijing, China. The Centre in Beijing adds considerable capacity to WHO GISRS to monitor circulating influenza viruses, particularly in Asia and China itself.

Image: The designation ceremony for the new WHO Collaborating Centre for Reference and Research on Influenza in Beijing was attended by Directors of the WHO Collaborating Centres in Atlanta, London, Melbourne and Tokyo; Prof Yuanji Guo (Former Director of the Chinese National Influenza Center) (front centre); Dr Wenqing Zhang (Global Influenza Programme, WHO Headquarters) (front, in blue); and staff of the new Centre.

The WHO Consultation on the Composition of Influenza Vaccines for the Northern Hemisphere 2011-2012 was held in Geneva on 14-17 February 2011. Following the Consultation, WHO made the following recommendation:

It is recommended that vaccines for use in the 2011-2012 influenza season (northern hemisphere) contain the following:

• an A/California/7/2009 (H1N1)-like virus;
• an A/Perth/16/2009 (H3N2)-like virus;
• a B/Brisbane/60/2008-like virus.

This is the same recommendation as the vaccine composition for the southern hemisphere 2011, indicating that the circulating viruses have not undergone significant antigenic drift since the last Consultation in September 2010.

The Influenza season has practically ended in Australia for 2010 with only sporadic cases being reported. The season which started later than usual peaked in September-October and then rapidly decreased. In New Zealand ILI activity has also returned to background levels after a moderate season which also started later than usually seen. By far the most commonly detected viruses in Australia have been pandemic H1N1 2009 viruses with around 81% of viruses being of this type and a small proportion (about 9%) being A(H3N2) viruses and B viruses (around 10%) (see here for viruses tested at WHO CC in 2010). In New Zealand nearly all viruses detected were H1N1 pandemic viruses with a small number of A(H3) and B viruses. No seasonal H1 viruses that circulated widely until the pandemic arose have been detected in Australia or New Zealand in 2010.

More information on the Australian and New Zealand influenza seasons is provided by the Australian Department of Health and Ageing and ESR, respectively . Low levels of influenza are circulating elsewhere in the region (see WHO FluNet).