Defense Date


Document Type


Degree Name

Master of Public Health


Epidemiology & Community Health

First Advisor

Christopher Buttery


Objective: 2009 H1N1 influenza was first detected in the Northern Hemisphere in April 2009. National data have suggested that the novel influenza virus disproportionately causes severe illness in children and young adults, a somewhat different presentation from traditional seasonal flu which normally strikes hardest in the very young and older adults. This may or may not be the case in Virginia, which, if it is different, may suggest a need to alter flu prevention messages and vaccine policy as the outbreak continues through the fall 2009-10 influenza season. This report examined the early presentation of the new influenza virus in Virginia, compared with the seasonal flu presentation. Methods: Surveillance data of influenza-like illness (ILI) visits to hospital emergency departments and urgent care centers for the period Oct. 2008 to Aug. 2009 were obtained from the Virginia Department of Health. The period from Oct. 2008-March 2009 was considered to be the normal flu season, while April-Aug. 2009 was considered as the 2009 (novel) H1N1 flu season. Descriptive statistics looked for differences by age, region and sex with respect to the proportion of visits that were for influenza-like illness compared to all reported illness for the normal and H1N1 flu seasons. Chi square and p-values were used to assess the level and significance of differences between flu seasons. Results: While the 2009 H1N1 influenza was a novel virus that, like all influenza viruses, could mutate and change into a form causing more severe illness, during the early months of the epidemic/pandemic, the virus did not appear to cause more illness as a percent of all illness compared to the preceding months of influenza in Virginia. Though it was unexpected to have influenza-like illness in the amount seen during April-August 2009, with several exceptions the level of flu-like illness compared to all illness was not higher than during the normal flu season immediately preceding the appearance of the 2009 H1N1 influenza. Conclusion: During the early months of the novel influenza H1N1 epidemic/pandemic in Virginia, the novel influenza virus caused levels of illness that were lower than levels of illness seen during the preceding normal flu season. Further study that examines the novel influenza virus through the end of the 2009-10 season may help to quantify the impact of the new virus. Flu-like illness reports spiked, for instance, as schools and colleges returned for fall 2009 semesters.


© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

December 2009

Included in

Epidemiology Commons