EU Recommendations for the Seasonal Influenza Vaccine Composition for the Season 2020/2021

messages in brief | 22/04/2020

The EMA adopted the new recommendations for the composition of seasonal influenza vaccines for the season 2020/2021 (published 1 April 2020).

Influenza viruses can be fatal (, but in contrast to a coronavirus (SARS-CoV-2) infection, preventive vaccination is a suggestive option. With that the risk to acquire an additional severe respiratory infection is significantly reduced.

The recommendations for the seasonal influenza vaccine composition have to be re-evaluated each year since influenza viruses are subject to a considerable antigenic variability and new viruses emerge.

Each year in March, European experts (Biologics Working Party Adhoc Influenza Working Group of the Human Medicines Committee (CHMP)) decide on the new composition based on recommendations published by the WHO. The timely recommendation allows manufacturers and regulators sufficient time to ensure availability of vaccines prior to start of the next influenza season.

The decision on which influenza or vaccine strains should be included in the seasonal influenza vaccines is based on epidemiologic and clinical findings from the Global Influenza Surveillance and Response System (GISRS) network: typically, new viruses emerge in Asia and spread via Europe towards the Americas and the southern hemisphere. For the purpose of virus surveillance, the GISRS including 146 National Influenza Centres in 122 WHO Member States collected and tested almost four million clinical specimens in the last year. Furthermore, additional data are considered to ensure that the recommended strains match as closely as possible the strains circulating next season therby contributing to vaccine effectiveness: serological and genetic characterization studies of recently circulating viruses, virus fitness forecasting, and vaccine effectiveness data (current season 2019/2020).

Taking into account the above information, trivalent vaccines in season 2020/2021 should contain

Egg-based Vaccines

  • an A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus;
  • an A/Hong Kong/2671/2019 (H3N2)-like virus; and
  • a B/Washington/02/2019 (B/Victoria lineage)-like virus.

Cell-based Vaccines

  • an A/Hawaii/70/2019 (H1N1)pdm09-like virus;
  • an A/Hong Kong/45/2019 (H3N2)-like virus; and
  • a B/Washington/02/2019 (B/Victoria lineage)-like virus.

Quadrivalent vaccines should contain in addition

  • a B/Phuket/3073/2013-like strain (B/Yamagata/16/88 lineage)

Compared to the previous season 2019/2020, the above recommendation differs with respect to the recommendation for influenza A (H1N1)pdm09, influenza A (H3N2) viruses and influenza B (Victoria lineage). Since the same strains are not optimal for both production in egg-based and cell-based production systems, different viruses are recommended for the influenza A(H1N1) and influenza A (H3N2) components. This facilitates timely vaccine production.


WHO recommended composition influenza vaccines 2020/2021

List of approved vaccines (AT)

Recommendations seasonal influenza vaccination (AT)


Further inquiry note