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News

01 Nov 2016

Historic change to southern hemisphere 2017 influenza vaccine

By Professor Ian Barr, Acting Director, WHO Collaborating Centre for Reference and Research on Influenza

The World Health Organisation (WHO) recently made an historic change to one of the components of the recommended influenza vaccine for the southern hemisphere in 2017.

For the first time since 2010 the A(H1N1)pdm09 subtype (H1pdm is the subtype responsible for the 2009 pandemic) component of the recommended vaccine has changed, after some 14 continuous recommendations for both the Northern and Southern Hemisphere vaccine compositions.

Twice a year, in February and September, the WHO Collaborating Centre for Reference and Research on Influenza located at the Doherty Institute, combines its surveillance data with four other such Collaborating Centres around the world for the WHO Consultation on the Composition of Influenza Vaccines. After the most recent consultation, held in Geneva in September, the following recommendation was made:

It is recommended that trivalent vaccines for use in the 2017 influenza season (southern hemisphere winter) contain the following:

  • an A/Michigan/45/2015 (H1N1)pdm09-like virus;
  • an A/Hong Kong/4801/2014 (H3N2)-like virus;
  • a B/Brisbane/60/2008-like virus.

It was also recommended that quadrivalent vaccines containing two influenza B viruses contain the above three viruses and a B/Phuket/3073/2013-like virus.

The update of the vaccine virus component to a Michigan-like virus was unusual as the basis for this decision was different from previous years. In the past, surface proteins of circulating viruses have been characterised mainly using blood serum samples derived from ferrets.

However, this time it was the interaction of human pre- and post-influenza vaccination blood serum samples with recent viruses that indicated the need for a more contemporary H1pdm vaccine virus.

While the H1pdm subtype viruses do not change as quickly as the A(H3N2) subtype viruses, it is unlikely that the Michigan-like viruses will enjoy such an extended run in the vaccine as the California-like viruses did – however, we will have to wait for a number of years to be sure. The other two components (in the trivalent vaccine) or three components (in the quadrivalent vaccine) were unchanged from the WHO 2016 Southern Hemisphere influenza vaccine recommendation.

The WHO consultation in September is especially important for the Centre at the Doherty Institute, as it is the only WHO Collaborating Centre for Influenza in the southern hemisphere, and the samples from the most recent influenza season (which coincides with the winter months here) are particularly important for providing information on the most recently circulating viruses.

Additionally, the recommendations arising from the September consultation are made for the southern hemisphere in the following year, which of course includes Australia and New Zealand but also covers a number of countries in the northern hemisphere such as the Philippines, Thailand and Malaysia whose influenza seasons match closest to ours.

While WHO makes recommendations for the influenza vaccine, it is up to national authorities to decide on the final composition for their individual countries, usually taking into account the WHO recommendation. The Australian Influenza Vaccine Committee met in Canberra at the beginning of October and decided that the influenza vaccine for Australia in 2017 is to be the same as the WHO recommendation.