1919. Partial Protection of Influenza Vaccine in a Primary Care Population Wisconsin: 2012-2015
Session: Poster Abstract Session: Vaccines: Influenza
Saturday, October 10, 2015
Room: Poster Hall
  • IDWeek - WIISP.pdf (783.7 kB)
  • Background: Annual influenza vaccination is recommended routinely for all persons aged 6 months and older for the prevention of influenza. Estimates of vaccine efficacy are based on differential rates of laboratory-confirmed influenza illness among vaccinated and unvaccinated persons. Little information exists on partial protection of vaccination, characterized as milder clinical presentation in patients with laboratory-confirmed influenza.

    Methods: The Wisconsin Influenza Incidence Surveillance Project (WIISP) conducted prospective surveillance in five primary care clinics for patients presenting with acute respiratory infections (>2 respiratory symptoms) from July 2012 through February 2015. Epidemiologic information and a nasopharyngeal swab were collected from each patient for influenza PCR. Influenza vaccination ≥14 days before the encounter was confirmed through chart audit with linkage to the Wisconsin Immunization Registry. Patients with PCR-confirmed influenza were categorized as meeting ILI criteria (fever with cough or sore throat) or having a non-ILI respiratory illness.  ILI has been shown in previous WIISP analyses to be associated with more severe clinical presentations. To assess the effect of influenza vaccination on the prevention of ILI, we calculated the odds of ILI according to vaccination status using binomial logistic regression, adjusting for age, time from illness onset, and sex.  Analyses combine all seasons; individual season evaluation was limited by sample size.

    Results: Acute respiratory infection visits were reported for 1,941 patients aged 18 days to 83 years (mean 34.3 years), of which 478 (24.6%) had laboratory-confirmed influenza.  Among influenza-positive patients, 342 (71.5%) met the ILI case criteria.  Receipt of influenza vaccine was identified for 132/338 (39.1%) patients with ILI compared with 73/129 (56.6%) among patients with non-ILI respiratory illness. The odds of ILI among vaccinated vs. unvaccinated patients was 0.62 (P<0.05; 95% CI: 0.40 – 0.96).

    Conclusion: The odds of meeting ILI criteria was 40% lower in vaccinated persons. Influenza vaccination may provide partial protection in the form of milder clinical illness in ambulatory patients with laboratory-confirmed influenza.

    Jonathan Temte, MD, PhD1, Shari Barlow, BA1, Maureen Landsverk, BS1, Amber Schemmel, BS1, Emily Temte, BA1, Kellie Kostopoulos, BS1, Thomas Haupt, MS2, Erik Reisdorf, MPH3, Mary Wedig, BS3, Peter Shult, PhD3, Andrea Steffens, MPH4 and Ashley Fowlkes, MPH4, (1)Family Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, (2)Bureau of Communicable Diseases, Wisconsin Division of Public Health, Madison, WI, (3)Communicable Disease Division, Wisconsin State Laboratory of Hygiene, Madison, WI, (4)Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA


    J. Temte, None

    S. Barlow, None

    M. Landsverk, None

    A. Schemmel, None

    E. Temte, None

    K. Kostopoulos, None

    T. Haupt, None

    E. Reisdorf, None

    M. Wedig, None

    P. Shult, None

    A. Steffens, None

    A. Fowlkes, None

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