title: Modeling seasonal influenza outbreak in a closed college campus: impact of pre-season vaccination, in-season vaccination and holidays/breaks.
abstract: BACKGROUND
  College and university students experience substantial morbidity from influenza and influenza-like illness, and they can benefit substantially from vaccination. Public health authorities encourage vaccination not only before the influenza season but also into and even throughout the influenza season. We conducted the present study to assess the impact of various vaccination strategies including delayed (i.e., in-season) vaccination on influenza outbreaks on a college campus.
  
  
  RESULTS
  We used a Susceptible --> Infected --> Recovered (SIR) framework for our mathematical models to simulate influenza epidemics in a closed, college campus. We included both students and faculty/staff in the model and derived values for the model parameters from the published literature. The values for key model parameters were varied to assess the impact on the outbreak of various pre-season and delayed vaccination rates; one-way sensitivity analyses were conducted to test the sensitivity of the model outputs to changes in selected parameter values. In the base case, with a pre-season vaccination rate of 20%, no delayed vaccination, and 1 student index case, the total attack rate (total percent infected, TAR) was 45%. With higher pre-season vaccination rates TARs were lower. Even if vaccinations were given 30 days after outbreak onset, TARs were still lower than the TAR of 69% in the absence of vaccination. Varying the proportions of vaccinations given pre-season versus delayed until after the onset of the outbreak gave intermediate TAR values. Base case outputs were sensitive to changes in infectious contact rates and infectious periods and a holiday/break schedule.
  
  
  CONCLUSIONS
  Delayed vaccination and holidays/breaks can be important adjunctive measures to complement traditional pre-season influenza vaccination for controlling and preventing influenza in a closed college campus.
authors.affiliation: Research Service, Veterans Affairs Medical Center, Minneapolis, Minnesota, United States of America. nicho014@umn.edu
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Nichol
authors.forename: Kate
authors.initials: K
authors.lastname: Tummers
authors.forename: Alanna
authors.initials: A
authors.lastname: Hoyer-Leitzel
authors.forename: Jennifer
authors.initials: J
authors.lastname: Marsh
authors.forename: Matt
authors.initials: M
authors.lastname: Moynihan
authors.forename: Steven
authors.initials: S
authors.lastname: McKelvey
mesh_terms: D004196:Disease Outbreaks / Q000517:prevention & control; D058872:Epidemics; D004813:Epidemiology; D006693:Holidays; D006801:Humans; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000453:epidemiology*; D008910:Minnesota; D008962:Models, Theoretical; D011634:Public Health; D012621:Seasons; D012680:Sensitivity and Specificity; D013334:Students; D014611:Vaccination
chemical_list: D007252:Influenza Vaccines