1521. School-Located Influenza Vaccinations Decrease Laboratory-Confirmed Influenza Rates and Improves School Attendance
Session: Poster Abstract Session: Influenza Vaccines
Saturday, October 20, 2012
Room: SDCC Poster Hall F-H
Posters
  • Pannaraj.IDSAPosterFinal10 2012.pdf (192.4 kB)
  • Background: School-located influenza vaccination (SLIV) programs have potential to efficiently immunize large numbers of school-aged children. We evaluated the impact of SLIV on laboratory-confirmed influenza and absenteeism.

    Methods: Active surveillance was conducted on 4465 children in 4 control and 4 SLIV intervention elementary schools (grades K-6) matched for sociodemographic characteristics in an urban community during the 2010-11 influenza season. Polymerase chain reaction for respiratory viruses was performed on nose and throat swabs collected from febrile children with influenza-like illness at presentation to the school nurse or during absenteeism. 

    Results: In the SLIV intervention schools, 27.8 to 47.3% of the students received at least one dose of influenza vaccine.  PCR results are available to date on 913 specimens obtained from 1030 children during the 15 week surveillence period. Specimens were positive for influenza in 208 (22.8%) including 2009 H1N1 (30.8%), H3 (8.7%) and B (60.6%);  101 (11.1%) were positive for other respiratory viruses. Influenza rates were higher in control schools compared to intervention (5.5 vs. 3.9 per 100 children, p=0.011). Unvaccinated children attending any school were 2.9 times more likely to acquire influenza compared to vaccinated children (5.2 vs. 1.6 per 100 children, p<0.001). Protection for unvaccinated children was only seen in the one school that achieved 47.3% vaccination rate (OR 2.1, p=0.039).  Absenteeism rates were higher in control compared to SLIV intervention schools (4.2 vs. 3.9 per 100 school days, p =0.023) during influenza season. Children with influenza missed a median of 2 days (range: 1-7 days) of school per illness episode compared to 1 day (range: 1-10 days) missed for children with other respiratory viruses (p<0.001). 

    Conclusion: Vaccination of at least a quarter of the school population results in decrease influenza rates and improves school attendance. Herd immunity for unvaccinated children may occur in schools with vaccination rates approaching 50 percent.

    Pia Pannaraj, MD, MPH, Infectious Diseases, Univerisity of Southern California and Children's Hospital Los Angeles, Los Angeles, CA, Alvin Nelson El Amin, MD, MPH, Immunization Program, Los Angeles County Department of Public Health, Los Angeles, CA, Hailin Wang, MPH, CIBMTR Milwaukee / Medical College of Wisconsin, Milwaukee, WI, Chrysanthy Ha, MPH, Uniformed Services University of the Health Sciences, Bethesda, MD, Hector Rivas, Los Angeles County Department of Public Health, Downey, CA, Michael Smit, MD, MSPH, Children's Hospital Los Angeles, Los Angeles, CA, Grace Aldrovandi, MD, University of Southern California and Children's Hospital Los Angeles, Los Angeles, CA and Laurene Mascola, MD, MPH, Los Angeles County Department of Public Health, Los Angeles, CA

    Disclosures:

    P. Pannaraj, None

    A. Nelson El Amin, None

    H. Wang, None

    C. Ha, None

    H. Rivas, None

    M. Smit, None

    G. Aldrovandi, None

    L. Mascola, Merck: Speaker's Bureau, Speaker honorarium
    MedImmune: Speaker's Bureau, Speaker honorarium

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