Seroprevalence and Severity of 2009 Pandemic Influenza A H1N1 in Taiwan
Author Information
Author(s): Chen Chih-Jung, Lee Ping-Ing, Chang Shih-Cheng, Huang Yhu-Chering, Chiu Cheng-Hsun, Hsieh Yu-Chia, Chang Shang-Chwen, Chang Feng-Yee, Lee Jen-Jyh, Su Shey-Chiang, Shen Gwan-Han, Chuang Yin-Ching, Chen Yao-Shen, Liu Jien-Wei, Lin Tzou-Yien
Primary Institution: Chang Gung Memorial Hospital
Hypothesis
What is the seroprevalence of the pandemic influenza A H1N1 virus in Taiwan before and after the 2009 pandemic, and how severe are the infections among different age groups?
Conclusion
The study found that pre-existing immunity against pH1N1 was rare in Taiwan before the pandemic, and young children and the elderly were the most vulnerable to severe disease after infection.
Supporting Evidence
- The overall seroprevalence of pH1N1 increased from 0.91% in 2007 to 29.9% in 2010.
- Children aged 0-5 years had a significantly higher rate of severe cases compared to adolescents aged 10-17 years.
- The overall case-fatality rate was 0.98 per 100,000 infections.
Takeaway
Before the pandemic, very few people in Taiwan had immunity to the H1N1 virus, but after the pandemic, about 30% of people had been infected, especially kids and older adults who got very sick.
Methodology
The study collected random serum samples from the general population in Taiwan in 2007 and 2010 to measure seroprevalence and severity of pH1N1 infections.
Potential Biases
Potential selection bias due to the sampling method and the influence of vaccination on seroprevalence estimates.
Limitations
The study was conducted 8 months after the pandemic, which may have led to antibody decay, and the seroprevalence data may not be generalizable to the entire population of Taiwan.
Participant Demographics
The study included participants from various age groups, with a focus on children and the elderly.
Statistical Information
P-Value
p<0.0001
Confidence Interval
95% CI 0.43–1.38 in 2007 and 95% CI 27.6–32.2 in 2010
Statistical Significance
p<0.0001
Digital Object Identifier (DOI)
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