Molecular epidemiology of influenza B virus and implications in immunization strategy, Southern Brazil. Issue 1 (2nd January 2018)

• Record Type: Journal Article
• Authors: Lapinscki, Bruna; Pereira, Luciane A.; Nogueira, Meri B.; Vidal, Luine R.; Riediger, Irina; Debur, Maria C.; Presibella, Mayra; Raboni, Sonia M.
• Is Part Of: Vaccine. Volume 36:Issue 1(2018)
• Page Start: 107
• Page End: 113
• Publication Date: 2018-01-02
• Subjects: Influenza B lineages -- Influenza vaccine -- Respiratory infection surveillance; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2017.11.033
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: In Brazil, from 2013 to 2016, Flu B accounted for 11.5% of the SARI cases but exhibited an increase of disease burden. In this report, Flu B strains were identified in 31% of influenza cases during four subsequent seasons. B/Yam and B/Vic lineages co-circulated in an alternating pattern with a frequency of 47% and 53%, respectively. Mismatching between the vaccine and the circulating strain occurred in the 2013 season, with a high concentration of SARI cases. Abstract: Epidemiological indicators have shown the substantial impact of influenza B (Flu B) on the development of severe acute respiratory infection (SARI) and on mortality rates. In Brazil, the trivalent vaccine, composed of only one Flu B lineage is available. We investigated Flu B infections in clinical samples collected by the epidemiological surveillance service of Paraná State, Brazil, from 2013 to 2016. The Flu B lineages Yamagata- (B/Yam) and Victoria-like (B/Vic) were identified using the qRT-PCR assay, and notification forms were reviewed. Among 379 Flu B positive samples evaluated, 370 (98%) were characterized as B/Yam or B/Vic lineages. Both co-circulated with a frequency of 47% and 53%, respectively. B/Yam infected equally both genders, while B/Vic was more frequent in females (71%). The median age of patients infected by B/Vic (23y; 11–35) was lower than that of patients infected by B/Yam (32y; 12–50). Mismatch between the vaccine and the circulating strain was observed in the 2013 season, with a high number of SARI cases. B/Vic lineage was associated with a larger number of SARI cases (62%), while B/Yam with influenza-like illness (ILI) (61%). Differences were observed in the strains circulating in separate regions of Paraná State. B/Vic was prevalent in the northwestern (67%) and B/Yam in the southeastern region (60%). The unpredictability of Flu B lineage circulation causes a substantial increase in severe disease during epidemics in a vaccine mismatch season. In addition, the differences in the epidemiological profile of the target population of Flu B infections in relation to other respiratory viruses, as well as among the B/Vic and B/Yam lineages may also be associated to an increase in disease burden. These findings have direct consequences on vaccination strategies. Therefore, further molecular epidemiology studies of Flu B in Brazil are required to corroborate these primary results.