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Fig. 5 | Virology Journal

Fig. 5

From: Correction: antigenic drift and immunity gap explain reduction in protective responses against influenza A(H1N1)pdm09 and A(H3N2) viruses during the COVID-19 pandemic: a cross-sectional study of human sera collected in 2019, 2021, 2022, and 2023

Fig. 5

Reduced HAI titers against A(H1N1)pdm09 clade 6B.1A.5a.2a.1 in 2022. A) Maximum parsimony tree of HA sequences of Norwegian A(H1N1)pdm09 strains from the 2022/2023 influenza season, including reference strains and vaccine strains for the southern and northern hemisphere. B) Residual serum samples from August 2022 with HAI titer of ≥ 160 against A/Victoria/2570/2019 (clade 6B.1A.5a.2) were evaluated in an HAI assay against the A(H1N1)pdm09 clade 6B.1A.5a.2a.1 strain A/Norway/25089/2022. B) Data presented is geometric mean with error bars representing 95% confidence interval. Significance was determined using a Wilcoxon matched-paired signed rank test. ** = p < 0.01, *** = p < 0.001 and**** = p < 0.0001

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Virology Journal

ISSN: 1743-422X