Patterns of influenza B circulation in Latin America and the Caribbean, 2010–2017

Abstract

Objective There are limited published data about the circulation of influenza B/Victoria and B/Yamagata in Latin America and the Caribbean (LAC) and most countries have a vaccine policy that includes the use of the trivalent influenza vaccine. We analyzed influenza surveillance data to inform decision-making in LAC about prevention strategies, such as the use of the quadrivalent influenza vaccine. Methods There are a total of 28 reference laboratories and National Influenza Centers in LAC that conduct influenza virologic surveillance according to global standards, and on a weekly basis upload their surveillance data to the open-access World Health Organization (WHO) platform FluNet. These data include the number of specimens tested for influenza and the number of specimens positive for influenza by type, subtype and lineage, all by the epidemiologic week of specimen collection. We invited these laboratories to provide additional epidemiologic data about the hospitalized influenza B cases. We conducted descriptive analyses of patterns of influenza circulation and characteristics of hospitalized cases. We compared the predominant B lineage each season to the lineage in the vaccine applied, to determine vaccine mismatch. A Chi-square and Wilcoxan statistic were used to assess the statistical significance of differences in proportions and medians at the P <0.05 level. Findings During 2010–2017, the annual number of influenza B cases in LAC was ~4500 to 7000 cases. Since 2011, among the LAC-laboratories reporting influenza B lineage using molecular methods, both B/Victoria and B/Yamagata were detected annually. Among the hospitalized influenza B cases, there were statistically significant differences observed between B/Victoria and B/Yamagata cases when comparing age and the proportion with underlying co-morbid conditions and with history of oseltamivir treatment ( P <0.001). The proportion deceased among B/Victoria and B/Yamagata hospitalized cases did not differ significantly. When comparing the predominant influenza B lineage detected, as part of surveillance activities during 63 seasons among 19 countries, to the lineage of the influenza B virus included in the trivalent influenza vaccine used during that season, there was a vaccine mismatch noted during 32% of the seasons analyzed. Conclusions Influenza B is important in LAC with both B/Victoria and B/Yamagata circulating annually in all sub regions. During approximately one-third of the seasons, an influenza B vaccine mismatch was identified. Further analyses are needed to better characterize the medical and economic burden of each influenza B lineage, to examine the potential cross-protection of one vaccine lineage against the other circulating virus lineage, and to determine the potential impact and cost-effectiveness of using the quadrivalent vaccine rather than the trivalent influenza vaccine.

Influenza vaccination hesitancy in five countries of South America. Confidence, complacency and convenience as determinants of immunization rates

“…Influenza vaccine has been reported with up to 90% of effectiveness in the case of healthy adults, while in older adults, effectiveness can be of 60% while reducing mortality by up to by 80% [4]. Some years, nevertheless, influenza vaccine can have a low performance due to a mismatch with circulating strains [5].…”

Key Factors That Enable the Pandemic Potential of RNA Viruses and Inter-Species Transmission: A Systematic Review

“…The importance to increase surveillance of viruses such as influenza-, corona-, and hanta- viruses, among other infectious agents of great importance to public health in Latin America, is well emphasized in several articles [ 50 , 51 , 52 , 53 , 54 , 55 ]. In 2015, influenza was considered the disease with the best simulation exercise completion index and nearly 85% of LAC said to have up-to-date contingency plans in case an emergency occurs.…”

Cost-Effectiveness Analysis of Switching from Trivalent to Quadrivalent Seasonal Influenza Vaccine in Argentina

“…The primary benefit of introducing QIV is the avoidance of mismatch between the predominant B strain circulating in the environment and the B strain included in the TIV formulation for a given season. A recent study by Palekar et al compared the B strains included in TIVs with environmental B strain predominance in Latin America and the Caribbean between 2010–2017 and found B strain mismatch to have occurred in 32% of seasons assessed [ 7 ]. When defining seasons of co-dominance between the B lineages as mismatch seasons, the rate of B strain mismatch during 2010–2017 increased to 52% of seasons [ 7 ].…”

“…A recent study by Palekar et al compared the B strains included in TIVs with environmental B strain predominance in Latin America and the Caribbean between 2010–2017 and found B strain mismatch to have occurred in 32% of seasons assessed [ 7 ]. When defining seasons of co-dominance between the B lineages as mismatch seasons, the rate of B strain mismatch during 2010–2017 increased to 52% of seasons [ 7 ]. These and other data demonstrate B strain mismatch to be a common occurrence across Latin American countries, including Argentina, and consequently indicate a need for QIV and the potential for improved public health as a result of its use.…”

“…Consequently, the development of quadrivalent influenza vaccines (QIVs) containing antigens derived from two A strains and the two B strains has been of significant benefit, with these vaccines offering additional protection compared with TIVs in terms of B strain mismatch [ 6 ]. As reported by Palekar et al, influenza viruses of both B/Yamagata and B/Victoria lineage circulate each year in Latin American and Caribbean countries, with 4500–7000 cases of B strain disease reported within the region annually during 2010–2017 [ 7 ]. Jamotte et al estimate that the use of QIV in Brazil, Colombia, and Panama would significantly reduce the burden of seasonal influenza disease in these countries [ 8 ].…”