TY - JOUR
T1 - Surveillance and Vaccine Effectiveness of an Influenza Epidemic Predominated by Vaccine-Mismatched Influenza B/Yamagata-Lineage Viruses in Taiwan, 2011-12 Season
AU - Lo, Yi Chun
AU - Chuang, Jen Hsiang
AU - Kuo, Hung Wei
AU - Huang, Wan Ting
AU - Hsu, Yu Fen
AU - Liu, Ming Tsan
AU - Chen, Chang Hsun
AU - Huang, Hui Hsun
AU - Chang, Chi Hsi
AU - Chou, Jih Haw
AU - Chang, Feng Yee
AU - Lin, Tzou Yien
AU - Chiu, Wen Ta
PY - 2013/3/5
Y1 - 2013/3/5
N2 - Introduction: The 2011-12 trivalent influenza vaccine contains a strain of influenza B/Victoria-lineage viruses. Despite free provision of influenza vaccine among target populations, an epidemic predominated by influenza B/Yamagata-lineage viruses occurred during the 2011-12 season in Taiwan. We characterized this vaccine-mismatched epidemic and estimated influenza vaccine effectiveness (VE). Methods: Influenza activity was monitored through sentinel viral surveillance, emergency department (ED) and outpatient influenza-like illness (ILI) syndromic surveillance, and case-based surveillance of influenza with complications and deaths. VE against laboratory-confirmed influenza was evaluated through a case-control study on ILI patients enrolled into sentinel viral surveillance. Logistic regression was used to estimate VE adjusted for confounding factors. Results: During July 2011-June 2012, influenza B accounted for 2,382 (72.5%) of 3,285 influenza-positive respiratory specimens. Of 329 influenza B viral isolates with antigen characterization, 287 (87.2%) were B/Yamagata-lineage viruses. Proportions of ED and outpatient visits being ILI-related increased from November 2011 to January 2012. Of 1,704 confirmed cases of influenza with complications, including 154 (9.0%) deaths, influenza B accounted for 1,034 (60.7%) of the confirmed cases and 103 (66.9%) of the deaths. Reporting rates of confirmed influenza with complications and deaths were 73.5 and 6.6 per 1,000,000, respectively, highest among those aged ≥65 years, 50-64 years, 3-6 years, and 0-2 years. Adjusted VE was -31% (95% CI: -80, 4) against all influenza, 54% (95% CI: 3, 78) against influenza A, and -66% (95% CI: -132, -18) against influenza B. Conclusions: This influenza epidemic in Taiwan was predominated by B/Yamagata-lineage viruses unprotected by the 2011-12 trivalent vaccine. The morbidity and mortality of this vaccine-mismatched epidemic warrants careful consideration of introducing a quadrivalent influenza vaccine that includes strains of both B lineages.
AB - Introduction: The 2011-12 trivalent influenza vaccine contains a strain of influenza B/Victoria-lineage viruses. Despite free provision of influenza vaccine among target populations, an epidemic predominated by influenza B/Yamagata-lineage viruses occurred during the 2011-12 season in Taiwan. We characterized this vaccine-mismatched epidemic and estimated influenza vaccine effectiveness (VE). Methods: Influenza activity was monitored through sentinel viral surveillance, emergency department (ED) and outpatient influenza-like illness (ILI) syndromic surveillance, and case-based surveillance of influenza with complications and deaths. VE against laboratory-confirmed influenza was evaluated through a case-control study on ILI patients enrolled into sentinel viral surveillance. Logistic regression was used to estimate VE adjusted for confounding factors. Results: During July 2011-June 2012, influenza B accounted for 2,382 (72.5%) of 3,285 influenza-positive respiratory specimens. Of 329 influenza B viral isolates with antigen characterization, 287 (87.2%) were B/Yamagata-lineage viruses. Proportions of ED and outpatient visits being ILI-related increased from November 2011 to January 2012. Of 1,704 confirmed cases of influenza with complications, including 154 (9.0%) deaths, influenza B accounted for 1,034 (60.7%) of the confirmed cases and 103 (66.9%) of the deaths. Reporting rates of confirmed influenza with complications and deaths were 73.5 and 6.6 per 1,000,000, respectively, highest among those aged ≥65 years, 50-64 years, 3-6 years, and 0-2 years. Adjusted VE was -31% (95% CI: -80, 4) against all influenza, 54% (95% CI: 3, 78) against influenza A, and -66% (95% CI: -132, -18) against influenza B. Conclusions: This influenza epidemic in Taiwan was predominated by B/Yamagata-lineage viruses unprotected by the 2011-12 trivalent vaccine. The morbidity and mortality of this vaccine-mismatched epidemic warrants careful consideration of introducing a quadrivalent influenza vaccine that includes strains of both B lineages.
UR - https://www.scopus.com/pages/publications/84874618250
UR - https://www.scopus.com/pages/publications/84874618250#tab=citedBy
U2 - 10.1371/journal.pone.0058222
DO - 10.1371/journal.pone.0058222
M3 - Article
C2 - 23472161
AN - SCOPUS:84874618250
SN - 1932-6203
VL - 8
JO - PLoS ONE
JF - PLoS ONE
IS - 3
M1 - e58222
ER -
