Pandemic Potential of a Strain of Influenza A (H1N1): Early Findings
Science·
- DOI
- 10.1126/science.1176062
- PMID
- 19433588
- PMCID
- PMC3735127
- OpenAlex
- W2157725602
- Study type
- Journal article
- Publisher
- American Association for the Advancement of Science (AAAS)
- Article type
- journal-article
- Integrity
- current
Why this research matters now
The findings provided early pandemic assessment crucial for informing health responses to a rapidly spreading novel influenza virus. Transmissibility was substantially higher than seasonal influenza and comparable to lower estimates from previous pandemics, while clinical severity appeared less than the 1918 pandemic but comparable to the 1957 pandemic.
Structured evidence summary
Research question
The study assessed the pandemic potential of a novel influenza A (H1N1) virus by estimating its transmissibility and clinical severity using early outbreak data from Mexico and information on international spread.
Study design
The authors conducted epidemiological and genetic analyses of the H1N1 outbreak in Mexico through late April, including assessment of a community outbreak in La Gloria, Veracruz, and examination of viral genetic diversity to estimate reproduction numbers and case fatality ratios.
Population and setting
The analysis focused on individuals infected in Mexico by late April, with detailed examination of a community outbreak in La Gloria, Veracruz. Clinical attack rates were stratified by age, with children under 15 years and adults 15 years and older analyzed separately.
Main findings
An estimated 23,000 individuals (range 6,000 to 32,000) had been infected in Mexico by late April, with a case fatality ratio of 0.4% (range 0.3% to 1.8%). The basic reproduction number was estimated at 1.4 to 1.6 by epidemiological methods and 1.2 by genetic analysis. Clinical attack rates in children were double those in adults (children <15 years: 61%; adults ≥15 years: 29%), and no deaths occurred in the La Gloria community outbreak (upper 95% bound CFR: 0.6%).
Public-health relevance
The findings provided early pandemic assessment crucial for informing health responses to a rapidly spreading novel influenza virus. Transmissibility was substantially higher than seasonal influenza and comparable to lower estimates from previous pandemics, while clinical severity appeared less than the 1918 pandemic but comparable to the 1957 pandemic.
Important limitations
The authors noted substantial uncertainty in their estimates due to limited data available at the time of early assessment. This summary is limited to the supplied single-article abstract and metadata and requires the original paper for decision-grade interpretation.
GIDS interpretation
This article would be discoverable through GIDS queries for novel influenza A, H1N1, outbreaks in Mexico, transmission dynamics studies, and pandemic assessment methodologies. The classifier links to diseases (Novel influenza A, Influenza), country (Mexico), and topics (Outbreak investigation, Transmission dynamics, Travel medicine) reflect the epidemiological focus and geographic scope of the early pandemic analysis.
Related GIDS surveillance
Literature context does not validate, explain, or change a surveillance signal. Exact and contextual relationships are shown separately.
Evidence relationships
This article has 9 auditable classifier relationships to diseases, places, topics, and study design.