One week after the World Health Organization (WHO) published their recommendations on the strains to be included in quadrivalent vaccines for use in the 2018-2019 northern hemisphere influenza season, the US Food and Drug Administration (FDA) weighed in with their vote as confirmed by a Vaccines and Related Biological Products Advisory Committee.

The following strains will be included in the 2018-2019 trivalent vaccine:
  • Influenza A/Michigan/45/2015 (H1N1)pdm09-like virus
  • Influenza A/Singapore/INFIMH-16-0019/2016 (H3N2)-like virus
    Replaces A/Hong Kong/4801/2014 (H3N2)-like virus from the 2017-2018 northern hemisphere influenza vaccine
  • Influenza B/Colorado/06/2017-like virus (B/Victoria/2/87 lineage)
    Replaces B/Brisbane/60/2008-like virus from the 2017-2018 northern hemisphere influenza vaccine
Quadrivalent vaccine addition:
Influenza B/Phuket/3073/2013-like virus (B/Yamagata/16/88 lineage)

WHO officials acknowledged in their recommendations that the change to include the A/Singapore/INFIMH-16-0019/2016-like virus is the result of the lack of activity against A(H3N2) viruses seen with the “egg-propagated A/Hong Kong/4801/2014 (H3N2)-like virus” included in the 2017-2018 vaccine. The WHO found that “recent A(H3N2) viruses were better inhibited by ferret antisera raised against the egg-propagated reference virus A/Singapore/INFIMH-16-0019/2016 compared to ferret antisera raised against other recent egg-propagated A(H3N2) viruses.”