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18 Oct 2018

WHO announces 2019 Southern Hemisphere influenza vaccine recommendations

The World Health Organisation (WHO) recently announced its recommendations for the composition of the influenza vaccine in the Southern Hemisphere for 2019.

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 the four other Collaborating Centres around the world for the WHO Consultation on the Composition of Influenza Vaccines.

It takes approximately six months to manufacture and distribute influenza vaccine, and therefore decisions about which virus strains should be included in each year’s vaccine need to be made in an appropriate time frame ahead of the influenza season in each of Southern and Northern Hemispheres.

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 includes Australia and New Zealand, as well as a number of countries in the Northern Hemisphere such as the Philippines, Thailand and Malaysia whose influenza seasons match closest to ours.

Centre Director Professor Kanta Subbarao, Deputy Director Professor Ian Barr and Head of Epidemiology Associate Professor Sheena Sullivan attended the most recent consultation, which was held in Atlanta, GA, USA in September.

Following the Consultation, WHO made the following recommendation:

It is recommended that egg based quadrivalent vaccines for use in the 2019 Southern Hemisphere influenza season contain the following:

  • an A/Michigan/45/2015 (H1N1)pdm09-like virus;
  • an A/Switzerland/8060/2017 (H3N2)-like virus;
  • a B/Colorado/06/2017-like virus (B/Victoria/2/87 lineage); and
  • a B/Phuket/3073/2013-like virus (B/Yamagata/16/88 lineage).

It is recommended that egg based trivalent vaccines for use in the 2019 Southern Hemisphere influenza season contain the following:

  • an A/Michigan/45/2015 (H1N1)pdm09-like virus;
  • an A/Switzerland/8060/2017 (H3N2)-like virus; and             
  • a B/Colorado/06/2017-like virus (B/Victoria/2/87 lineage).

It is recommended that the A(H3N2) component of non-egg based vaccines for use in the 2019 Southern Hemisphere influenza season be an A/Singapore/INFIMH-16-0019/2016-like virus together with the other vaccine components as indicated above.

The recommendation includes a change in the A(H3N2) component of the vaccine when it is produced in eggs, as is the case in Australia. Surface proteins of circulating viruses are analysed mainly using sera derived from ferrets following infection with influenza viruses (ferret antisera).

It was found that a larger proportion of recently circulating viruses were well inhibited by ferret antisera produced using the new vaccine virus A/Switzerland/8060/2017 which had been produced in eggs compared to the previous egg-based vaccine strain (A/Singapore/INFIMH-16-0019/2016).

This suggests that vaccines containing egg-based A/Switzerland/8060/2017 would produce better protection against future circulating viruses than the previous vaccine strain.

The B/Victoria component of the recommended vaccine has also changed because globally, an increasing proportion of circulating viruses are similar to B/Colorado/6/2017 and different from the previous vaccine virus (B/Brisbane/60/2008).   

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 in October and adopted the recommendations made by WHO for the quadrivalent vaccine.

However, the recommendation for the Australian trivalent vaccine includes a B/Yamagata lineage virus, rather than the B/Victoria lineage virus recommended by WHO. This is because in Australia, the vast majority of recently circulating influenza B viruses have been of the B/Yamagata lineage and the number of circulating B/Victoria viruses has been negligible.

CLICK HERE to see the current WHO and Australian influenza vaccine recommendations.

CLICK HERE for the full WHO recommendations.

CLICK HERE for the Australian influenza vaccine recommendations.