Smallpox and Season: Reanalysis of Historical Data
2009
Smallpox and Season: Reanalysis of Historical Data
Sample size: 7
publication
Evidence: moderate
Author Information
Author(s): Nishiura Hiroshi, Kashiwagi Tomoko
Hypothesis
Is smallpox transmission really seasonal, and is the seasonality associated with humidity?
Conclusion
The study confirms that smallpox transmission varies with season and is most likely enhanced by dry weather.
Supporting Evidence
- Annual cycles of smallpox transmission were shown in both monthly reports and estimates of the effective reproduction number.
- Humidity was found to have a significant negative association with smallpox mortality.
- Short-term epidemic data showed peaks of smallpox transmission every January.
Takeaway
This study looked at old data about smallpox to see if it spreads more in certain seasons, and it found that dry weather makes it spread more.
Methodology
The study reanalyzed seven historical datasets of smallpox cases and deaths, using time series analysis and estimating the effective reproduction number.
Limitations
Some important meteorological variables, like temperature, were missing from the analysis.
Statistical Information
P-Value
<0.01
Confidence Interval
(0.311, 0.481)
Statistical Significance
p<0.01
Digital Object Identifier (DOI)
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