Here's the WHO's recommendation for 2020-2021 flu vaccine composition for northern hemisphere:

https://www.who.int/influenza/vaccines/virus/..._north/en/

The quadrivalent vaccines are the two each of Type-A and B strains.

The trivalent vaccines are the two of Type-A and one of the Type-B strain.

Quote:

---

Recommended composition of influenza virus vaccines for use in the 2020 - 2021 northern hemisphere influenza season
28 February 2020
It is recommended that quadrivalent vaccines for use in the 2020 - 2021 northern hemisphere influenza season contain the following:

Egg-based Vaccines
an A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus;
an A/Hong Kong/2671/2019 (H3N2)-like virus;
a B/Washington/02/2019 (B/Victoria lineage)-like virus; and
a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

Cell- or recombinant-based Vaccines
an A/Hawaii/70/2019 (H1N1)pdm09-like virus;
an A/Hong Kong/45/2019 (H3N2)-like virus;
a B/Washington/02/2019 (B/Victoria lineage)-like virus; and
a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

It is recommended that trivalent influenza vaccines for use in the 2020 - 2021 northern hemisphere influenza season contain the following:

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- or recombinant-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.

---

The full report: https://www.who.int/influenza/vaccines/virus/...n.pdf?ua=1