Key points

• Outbreak lasting 9 weeks

• Late epidemic peak (early April)

• Moderate intensity in community practice and hospitals

• Co-circulation of A(H3N2) and A(H1N1)pdm09 viruses

• More pronounced impact among children, with high intensity at the peak of the outbreak

• Vaccination coverage higher than in 2019–20 but lower than in 2020–21

• High vaccine efficacy against A(H1N1)pdm09 and low against A(H3N2)