Interim 2022/23 influenza vaccine effectiveness: six European studies, October 2022 to January 2023

Article Infectious Diseases

Vaccine effectiveness estimates from an early-season influenza A(H3N2) epidemic, including unique genetic diversity with reassortment, Canada, 2022/23

Danuta M. Skowronski et al.

Summary: The Canadian Sentinel Practitioner Surveillance Network estimated the vaccine effectiveness (VE) during the early 2022/23 influenza A(H3N2) epidemic. Both the vaccine and circulating viruses belonged to clade 3C.2a1b.2a.2, but there was genetic diversity at hemagglutinin positions 135 and 156, and reassortment resulted in H156 viruses acquiring neuraminidase from clade 3C.2a1b.1a. The vaccine provided substantial protection with an overall VE of 54% (95% CI: 38 to 66) against A(H3N2). The VE was similar for H156 and vaccine-like S156 viruses, but there could be potential variation based on diversity at position 135.

EUROSURVEILLANCE (2023)

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Article Infectious Diseases

Influenza vaccine effectiveness against influenza A subtypes in Europe: Results from the 2021-2022 I-MOVE primary care multicentre study

Esther Kissling et al.

Summary: In the 2021-2022 influenza season, influenza A viruses were dominant in Europe. A multicentre test-negative study conducted by the I-MOVE primary care network showed that the overall vaccine effectiveness against A(H1N1)pdm09 was 75% and against A(H3N2) was 29%. The highest vaccine effectiveness was observed among individuals aged 15-64 years for both influenza A subtypes. The study also found that despite antigenic mismatch, the vaccine was still able to provide protection against laboratory-confirmed influenza among those vaccinated.

INFLUENZA AND OTHER RESPIRATORY VIRUSES (2023)

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Article Infectious Diseases

A late sharp increase in influenza detections and low interim vaccine effectiveness against the circulating A(H3N2) strain, Denmark, 2021/22 influenza season up to 25 March 2022

Hanne-Dorthe Emborg et al.

EUROSURVEILLANCE (2022)

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Article Multidisciplinary Sciences

Substitutions near the HA receptor binding site explain the origin and major antigenic change of the B/Victoria and B/Yamagata lineages

Miruna E. Rosu et al.

Summary: This study investigates the antigenic diversity and evolution of influenza B virus, focusing on two antigenic variants - Victoria-like and Yamagata-like. The researchers analyze a collection of historical virus isolates and determine their antigenic properties. They find that amino acid substitutions at specific positions near the receptor binding site play a major role in antigenic differences. Surprisingly, recent viruses of the Victoria lineage show antigenic properties similar to those circulating 50 years ago.

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (2022)

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Article Infectious Diseases