Taiwan's Response to Influenza: A Seroepidemiological Evaluation of Policies and Implications for Pandemic Preparedness. (August 2022)

• Record Type: Journal Article
• Authors: Ho, Pui-I; Liu, Wei; Li, Tiger Zheng-Rong; Chan, Ta-Chien; Ku, Chia-Chi; Lien, Yu-Hui; Shen, Yea-Huei Daphne; Chen, Juine-Ruey; Yen, Muh-Yong; Tu, Yu-Kang; Lin, Wan-Yu; Compans, Richard; Lee, Ping-Ing; King, Chwan-Chuen
• Is Part Of: International journal of infectious diseases. Volume 121(2022)
• Page Start: 226
• Page End: 237
• Publication Date: 2022-08
• Subjects: pandemic influenza -- emerging infectious diseases -- public health policy -- vaccination -- seroepidemiology -- Taiwan; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2022.02.038
• Languages: English
• ISSNs: 1201-9712

Abstract

ABSTRACT: Objectives: To evaluate class suspension and mass vaccination implemented among Taipei schoolchildren during the 2009 influenza pandemic and investigate factors affecting antibody responses. Methods: We conducted 2 cohort studies on: (1) 972 schoolchildren from November 2009–March 2010 to evaluate pandemic policies and (2) 935 schoolchildren from November 2011–March 2012 to verify factors in antibody waning. Anti-influenza H1N1pdm09 hemagglutination inhibition antibodies (HI-Ab) were measured from serum samples collected before vaccination, and at 1 and 4 months after vaccination. Factors affecting HI-Ab responses were investigated through logistic regression and generalized estimating equation. Results: Seroprevalence of H1N1pdm09 before vaccination was significantly higher among schoolchildren who experienced class suspensions than those who did not (59.6% vs 47.5%, p<0.05). Participating in after-school activities (adjusted odds ratio [aOR]=2.47, p=0.047) and having ≥3 hours per week of exercise (aOR=2.86, p=0.019) were significantly correlated with H1N1pdm09 infection. Two doses of the H1N1pdm09 vaccine demonstrated significantly better antibody persistence than 1 dose (HI-Ab geometric mean titer: 132.5 vs 88.6, p=0.047). Vaccine effectiveness after controlling for preexisting immunity was 86% (32%-97%). Exercise ≥3 hours per week and preexisting immunity were significantly associated with antibody waning/maintenance. Conclusions: This study is the first to show that exercise and preexisting immunity may affect antibody waning. Further investigation is needed to identify immune correlates of protection.