In September 2022 the WHO announced its recommendation for the viral composition of influenza vaccines for the 2023 southern hemisphere influenza season. These recommendations inform the development, production, and licensing of influenza vaccines by regulatory agencies and pharmaceutical companies.
New year, new flu
The WHO suggests that the “periodic update of viruses contained in influenza vaccines” is important because of the “constantly evolving nature of influenza viruses”. Each year a group of experts from WHO Collaborating Centres and WHO Essential Regulatory Laboratories analyse “virus surveillance data” from the WHO Global Influenza Surveillance and Response System (GISRS). This is a “global network” comprising more than 150 labs in 127 countries and areas, founded in 1952. Vaccine composition recommendations are issued twice a year.
Recommended recipes
The estimation from WHO is that “around a billion people” get seasonal influenza each year. In the hope of keeping the consequences at bay, the WHO is recommending that quadrivalent vaccines for this year’s season contain:
Egg-based vaccines:
- an A/Sydney/5/2021 (H1N1)pdm09-like virus;
- an A/Darwin/9/2021 (H3N2)-like virus;
- a B/Austria/1359417/2021 (B/Victoria lineage)-like virus; and
- a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.
Cell culture- or recombinant-based vaccines
- an A/Sydney/5/2021 (H1N1)pdm09-like virus;
- an A/Darwin/6/2021 (H3N2)-like virus;
- a B/Austria/1359417/2021 (B/Victoria lineage)-like virus; and
- a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.
The trivalent vaccine recommendation contains the following:
Egg-based vaccines
- an A/Sydney/5/2021 (H1N1)pdm09-like virus;
- an A/Darwin/9/2021 (H3N2)-like virus; and
- a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.
Cell culture- or recombinant-based vaccines
- an A/Sydney/5/2021 (H1N1)pdm09-like virus;
- an A/Darwin/6/2021 (H3N2)-like virus; and
- a B/Austria/1359417/2021 (B/Victoria lineage)-like virus
GISRS goes forward
The GISRS celebrates 70 years in 2022. The WHO suggests that it increased its “added value to other respiratory virus threats” such as COVID-19 and continues to look ahead. The WHO Director General, Dr Tedros Adhanom Ghebreyesus, believes it has been a success so far.
“GISRS is a proven global network that has provided a first line of defence against influenza for 70 years.”
In the future, GISRS will “continue to use its unique position as a global respiratory surveillance network”. The WHO hopes that it will evolve with “emerging technologies”, such as genomic surveillance, to continue offering protection against the “threat of influenza”.
With these most recent recommendations, discussion about the benefits of a “universal flu” inevitably return to the table. To read more about what this might mean, click here.
For more on influenza at the World Vaccine Congress in Europe, 2022, get your tickets here.
