Identifying Influenza Cases During the H1N1 Pandemic in Massachusetts
Author Information
Author(s): Placzek Hilary, Madoff Larry
Primary Institution: University of Massachusetts Medical School
Hypothesis
To characterize the epidemiology of H1N1-related hospitalizations in Massachusetts and compare characteristics of those hospitalized during seasonal influenza and the H1N1 pandemic.
Conclusion
The study found that large administrative data sets can detect hospitalizations for influenza during a pandemic, but estimated case counts vary widely depending on the selection criteria used.
Supporting Evidence
- During spring and summer 2009, there were significantly higher rates of ILI-related hospital discharges in Massachusetts compared to 2005-2008.
- H1N1 affected a younger population with 50% being under 18 years old.
- H1N1-related hospitalizations ranged from 601 to 10,967 cases during the pandemic.
- ICU admission rates were higher for H1N1 cases compared to seasonal influenza.
- Maximum criteria overestimated H1N1 activity, while minimum criteria provided a more accurate estimate.
Takeaway
This study looked at how many people got sick from H1N1 in Massachusetts and found that many were younger and from minority groups.
Methodology
The study used the Massachusetts Hospital Discharge Database to identify H1N1-related hospitalizations and compared data from 2005-2008 to 2009.
Potential Biases
Potential misclassification of non-influenza cases as influenza cases due to the broad selection criteria.
Limitations
Data from correctional facilities and veteran’s hospitals were not included, and the study could not compare hospitalized cases to non-hospitalized cases.
Participant Demographics
50% of hospitalized H1N1 cases were under 18 years old, with higher rates among African-Americans (18%) and Hispanics (23%).
Statistical Information
P-Value
p<0.05
Confidence Interval
95% CI
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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