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

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.

• Authors: Pui-I Ho, Wei Liu, Tiger Zheng-Rong Li, Ta-Chien Chan, Chia-Chi Ku, Yu-Hui Lien, Yea-Huei Daphne Shen, Juine-Ruey Chen, Muh-Yong Yen, Yu-Kang Tu, Wan-Yu Lin, Richard Compans, Ping-Ing Lee, Chwan-Chuen King
• Journal: International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases (Int J Infect Dis) Vol. 121 Pg. 226-237 (Aug 2022) ISSN: 1878-3511 [Electronic] Canada
• PMID: 35235824 (Publication Type: Journal Article)
• Copyright: Copyright © 2022. Published by Elsevier Ltd.

Chemical References

• Antibodies, Viral
• Influenza Vaccines

Topics

• Antibodies, Viral
• Child
• Hemagglutination Inhibition Tests
• Humans
• Influenza A Virus, H1N1 Subtype
• Influenza Vaccines
• Influenza, Human (epidemiology, prevention & control)
• Pandemics (prevention & control)
• Policy
• Seroepidemiologic Studies
• Taiwan (epidemiology)
• Vaccination