Recommended composition of influenza virus vaccines for use in the 2022 southern hemisphere influenza season/ Composition recommandee des vaccins antigrippaux pour la saison grippale 2022 dans l'hemisphere Sud.

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Date: Oct. 22, 2021
From: Weekly Epidemiological Record(Vol. 96, Issue 42)
Publisher: World Health Organization
Document Type: Article
Length: 7,606 words
Lexile Measure: 1710L

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September 2021

WHO convenes technical consultations (1) in February and September each year to recommend viruses for inclusion in influenza vaccines (2) for the northern and southern hemisphere influenza seasons, respectively. This recommendation relates to the influenza vaccines for use in the southern hemisphere 2022 influenza season. A recommendation will be made in February 2022 relating to vaccines that will be used for the northern hemisphere 2022-2023 influenza season. For countries in tropical and subtropical regions, WHO recommendations for influenza vaccine composition (northern hemisphere or southern hemisphere) are available on the WHO Global Influenza Programme website. (3)

Seasonal influenza activity

Greatly reduced numbers of influenza viruses were available for characterization during the 01 February to 31 August 2021 time-period than in previous years. SARS-CoV-2 mitigation strategies including travel restrictions, use of personal protective equipment and social-distancing measures in several countries contributed to decreased influenza activity. Furthermore, public health and laboratory responses to the COVID-19 pandemic, caused by SARS-CoV-2, may have led to reduced influenza surveillance and/or reporting activities in some countries (Map 1).

From February through August 2021, very low levels of influenza were reported in all regions, including from countries in the temperate zone of the southern hemisphere. During this period, influenza A(H1N1)pdm09, A(H3N2) and influenza B viruses circulated, although the proportions of the viruses circulating varied among reporting countries.

In the temperate zone of the northern hemisphere, influenza activity remained well below inter-seasonal norms with very low-level detections of influenza A and/or B viruses in most reporting countries. There were only sporadic detections of influenza A and B viruses in Europe with a predominance of influenza A viruses. Of the influenza A viruses where subtyping was performed, A(H1N1)pdm09 was detected more frequently than A(H3N2). Influenza virus detections were reported mainly by Denmark, Norway, Sweden, and the United Kingdom of Great Britain and Northern Ireland. In Asia, the proportions of influenza A and B viruses detected differed among reporting countries. In China, Pakistan, Qatar and Saudi Arabia, influenza B was predominant, while in the Democratic People's Republic of Korea, influenza A was predominant with A(H1N1) pdm09 and A(H3N2) viruses detected in almost equal proportions. Of the influenza B viruses in Asia where lineage was determined, the great majority belonged to the B/Victoria/2/87 lineage. In North America, equal proportions of influenza A and B viruses were reported. In Africa, Egypt reported influenza A(H3N2) and influenza B activity from April to July, with a predominance of A(H3N2) viruses. In other regions of the temperate zone of the northern hemisphere, there was little or no influenza activity reported during this period.

Influenza activity in tropical and subtropical countries was generally very low in comparison to influenza seasons prior to the COVID-19 pandemic. While influenza A and B were reported in varying proportions by countries in Africa and Asia, there was an overall predominance of influenza A viruses. In east African countries, there was a predominance of influenza A(H3N2), followed by influenza B and A(H1N1)pdm09, with the majority of these detections reported by...

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Gale Document Number: GALE|A681025599