J Med Virol . Surveillance of influenza B severe hospitalized cases during ten seasons in Catalonia. Does the lineage make a difference?

[tetano]

J Med Virol


. 2022 May 20.
doi: 10.1002/jmv.27876. Online ahead of print.
Surveillance of influenza B severe hospitalized cases during ten seasons in Catalonia. Does the lineage make a difference?


Núria Soldevila ¹ , Luca Basile ² , Ana Martínez ^{2 3} , Núria Torner ^{1 3} , M Ángeles Marcos ⁴ , MMar Mosquera ⁴ , Andrés Antón ^{5 6} , Cristina Andrés ^{5 6} , Cristina Rius ^{3 7} , Tomàs Pumarola ^{5 6} , Ángela Domínguez ^{1 3} , and the PIDIRAC Surveillance of Hospitalized Cases of Severe Influenza in Catalonia Working Group



Affiliations

• PMID: 35593301
• DOI: 10.1002/jmv.27876

Abstract

Introduction: Influenza B viruses circulates in two lineages (B/Victoria and B/Yamagata). Although classically affecting children, recently it has shown high rate of infection and increased hospitalization in the elderly.
Objective: To describe and analyze the clinical and epidemiological characteristics of severe hospitalized laboratory confirmed influenza B virus (SHLCI-B) cases in Catalonia associated to mismatch from Influenza B virus strain included in the trivalent influenza vaccine (TIV).
Methods: SHLCI-B registered by the influenza sentinel surveillance system of Catalonia (PIDIRAC) during ten surveillance seasons from 2010 to 2020. Variables age, comorbidities, vaccination status were recorded. Vaccine effectiveness was estimated as (1-OR) for intensive care unit (ICU) admission. Statistical significance was established at p <0.05.
Results: A total of 1159 SHLCI-B were registered, of these 68.2% (791) corresponded to the 2017-18 season; 21.8% (253) were admitted to ICU and 13.8% (160) were exitus; 62.5% (725) cases occurred in those aged > 64 years; most frequent risk factor was cardiovascular disease (35.1%, 407) followed by chronic pulmonary obstructive disease-COPD (24.6%, 285) and diabetes (24.1%, 279). In 4 seasons, the predominant circulating lineage was B/Victoria, in 2 seasons the B/Yamagata lineage and 4 seasons had no IBV activity. Four seasons presented discordance with the strain included within the TIV. Vaccine effectiveness (VE) to prevent ICU admission was 31% (95% CI: 4-51%; p=0.03); being 29% (95%CI: -3%, 51%) in discordant and 43% (95% CI:-43%, 77%) in concordant seasons. Significant differences were observed in the number of affected aged > 64 years (OR=2.5; 95% CI: 1.9-3.4; p <0.001) and in patients with heart disease (OR = 2.40 95% CI: 1.7-3.4; p <0.001), COPD (OR = 1.6 95% CI: 1.1-2.3; p = 0.01) and diabetes (OR = 1.5 95% CI: 1.1-2.1; p = 0.04) between discordant and concordant seasons.
Conclusions: The increase in hospitalization rate in people> 64 years of age and those presenting comorbidities in seasons with circulating influenza B virus belonging to a lineage discordant with the strain included in the TIV and the decrease of VE to prevent ICU admissions evidences the vital need to administer the quadrivalent influenza vaccine regardless of the findings of predominant circulation in the previous season. This article is protected by copyright. All rights reserved.

Keywords: Influenza B virus; Lineage; Surveillance; Vaccine.