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The 2019-2020 flu season is regarded as one of the most serious ones in decades. Previous researchers usually studied the effects of different factors on seasonal flu separately instead of their conjugate impact, so we wanted to find how multiple factors combine to affect the spread of influenza in the 2019-2020 flu season in America. We chose types of virus (A and B), environmental factors (temperature, precipitation, relative humidity), population density, and influenza vaccination status for different age groups which are statewide data containing monthly information from Sep. 2019 to May 2020. By principal component analysis, we could see the importance of different factors as well as the general relationship between them. Furthermore, using path analysis enabled us to investigate the causal relationship between factors more precisely than the previous method. We found that two virus types have different relationship patterns with other remaining variables: Type A virus is strongly negatively related to temperature (lower temperature tends to cause more cases), and is also somewhat related to some vaccination groups, while the significance of any vaccination group doesn’t show up in Type B virus. Moreover, there are relationships between factors, like the vaccination rates for different age groups are strongly correlated to each other. Our findings could provide general advice to you during flu season. For instance, if the temperature is relatively low one year, then you could be aware that it’s more likely for you to be infected. In addition, since the influenza situation is somewhat similar to COVID-19, our findings might also be helpful for you to protect yourself.

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Influenza--United States, Influenza--Statistics


Applied Statistics | Influenza Humans


Faculty Adviser: Engin Sungur

Conjunction of Factors Impacting the 2019-2020 Flu Season in the US