How the H1N1 influenza epidemic spread among university students in Japan: experience from Shinshu University

Abstract

Background: A worldwide outbreak of influenza A/H1N1 occurred in 2009. Little information is available regarding how the epidemic spread among young people, who composed the majority of individuals infected with this virus. We assessed the route of transmission of H1N1 among university students at Shinshu University, Japan.

Methods: A total of 11,424 students were monitored between August 2009 and March 2010, and those who were diagnosed with confirmed, probable, or suspected H1N1 at a hospital or clinic were registered based on self-report to the university. Data including date of onset and suspected infection route were collected from the affected patients.

Results: Of the 11,424 students, 1,016 (8.9%) were infected with H1N1. In most infected students, the suspected transmission route was associated with club activity, followed by close contact with friends and through lectures or laboratory work. After suspension of activity by clubs with more than 2 infected members, the number of infected individuals decreased.

Conclusion: H1N1 influenza spread in the university through specific routes, including club activity, close contact with friends, and lectures or laboratory work. During future outbreaks of influenza, interventions to reduce transmission through these routes may be effective infection control strategies in university students.