Literature review of the epidemiology of influenza B disease in 15 countries in the Asia‐Pacific region

Abstract

Influenza control strategies focus on the use of trivalent influenza vaccines containing two influenza A virus subtypes and one of the two circulating influenza type B lineages (Yamagata or Victoria). Mismatches between the vaccine B lineage and the circulating lineage have been regularly documented in many countries, including those in the Asia‐Pacific region. We conducted a literature review with the aim of understanding the relative circulation of influenza B viruses in Asia‐Pacific countries. PubMed and Western Pacific Region Index Medicus were searched for relevant articles on influenza type B published since 1990 in English language for 15 Asia‐Pacific countries. Gray literature was also accessed. From 4834 articles identified, 121 full‐text articles were analyzed. Influenza was reported as an important cause of morbidity in the Asia‐Pacific region, affecting all age groups. In all 15 countries, influenza B was identified and associated with between 0% and 92% of laboratory‐confirmed influenza cases in any one season/year. Influenza type B appeared to cause more illness in children aged between 1 and 10 years than in other age groups. Epidemiological data for the two circulating influenza type B lineages remain limited in several countries in the Asia‐Pacific, although the co‐circulation of both lineages was seen in countries where strain surveillance data were available. Mismatches between circulating B lineages and vaccine strains were observed in all countries with available data. The data suggest that a shift from trivalent to quadrivalent seasonal influenza vaccines could provide additional benefits by providing broader protection.

Circulation and characterization of seasonal influenza viruses in Cambodia, 2012‐2015

“…This pattern of influenza B circulation has previously been noted in Cambodia and other countries globally . Seasonal influenza vaccination is not widespread in Cambodia, but considering the co‐circulation of both influenza B lineages in most years since surveillance began in 2006, and the frequent mismatch between strains included in the TIIVs and the most dominant circulating influenza B lineage, the introduction of the quadrivalent seasonal influenza vaccine might be worthwhile, especially in young children, as this covers both lineages of influenza B virus and both subtypes of seasonal influenza A viruses …”

“…cluded in the TIIVs and the most dominant circulating influenza B lineage, the introduction of the quadrivalent seasonal influenza vaccine might be worthwhile, especially in young children, as this covers both lineages of influenza B virus and both subtypes of seasonal influenza A viruses 22. Sequence analysis of the matrix gene from representative Cambodian isolates suggested that resistance to adamantanes is common, as all isolates obtained during this period contained the Ser31Asn mutation in the M2 protein.…”

Comparative global epidemiology of influenza, respiratory syncytial and parainfluenza viruses, 2010–2015

“…over the same time period) incidence patterns of common respiratory viruses across different countries -and nearly all of these used mostly publicly available surveillance data extracted from national surveillance websites, or published studies. [31][32][33][34][35] However, it is clear from the literature that international collaborations are increasing, in an effort to pool and compare such contemporaneous epidemiological data, to improve our understanding of how these respiratory viruses are behaving -not just within our local or national populations, but simultaneously across the world. Although national surveillance data are invaluable to reveal how these viruses are behaving and moving through populations, and also capture the incidence of viral infections in the community to some extent, the bulk of that population's healthcare burden may be more accurately represented by the routine diagnostic testing data obtained from patients who were sufficiently ill to be admitted to hospital.…”

Development of Influenza B Universal Vaccine Candidates Using the “Mosaic” Hemagglutinin Approach

“…I nfluenza B viruses almost exclusively infect humans and can cause severe disease and even death (1)(2)(3). Children who lack preexisting immunity to influenza viruses are more susceptible to type B virus infection than adults (4)(5)(6). Globally, about 25% of all influenza virus-positive clinical cases are caused by influenza B viruses (7), and occasionally, influenza B viruses dominate influenza seasons (8)(9)(10)(11).…”