485. Influenza Infection in the Department of Veterans Affairs (VA): 2014-2015
Session: Poster Abstract Session: Respiratory Infections: Influenza
Thursday, October 8, 2015
Room: Poster Hall
Posters
  • Schirmer IDWeek 2015 Influenza Infection 2014-2015 Poster.pdf (5.4 MB)
  • Background: Influenza is associated with significant morbidity and mortality and VA's large elderly population is at risk.  We conduct ongoing surveillance and herein describe 2014-15 national influenza activity in VA.

    Methods: Percent influenza-like illness (ILI); hospitalizations and deaths; outpatient visits; telephone triage; antiviral use; and laboratory testing from 9/28/14-5/9/15 were obtained using VA data warehouses, and compared to 3 previous seasons.  A convenience sample of positive nasopharyngeal specimens underwent hemagglutinin (HA) and neuraminidase (NA) gene sequencing.

    Results:   ILI varied from 1.1-4.3% during the season.  Surveillance metrics are reported in Table 1 and Figure 1.  For the season, 840 were typed/subtyped for H1N1 (1[0.1%]), H3N2 (810[96%]), and B (29[3%]) strains. Of 820 strains tested for NA inhibitor resistance, 1 possessed mutation conferring resistance (I222V).  Compared to 2014-15 vaccine strains, amino acid changes were seen in HA gene epitopes among all strains (Figure 2).

    Table 1. VA Influenza Surveillance Metrics, by Season 

     

    2011-12

    N (%)

    2012-13

    N (%)

    2013-14

    N (%)

    2014-15

    N (%)

    Influenza-coded hospitalizations

          Unique patients

                Deaths

                Positive influenza test

                Antiviral prescribed

    553

    545

    19 (3)

    288 (53)

    256 (47)

    2524

    2490

    71 (3)

    1492 (60)

    1628 (65)

    2405

    2366

    74 (3)

    1654 (70)

    1592 (67)

    3503

    3447

    108 (3)

    2780 (81)

    2454 (71)

    Influenza tests performed

          Total positive

                Influenza A

                Influenza B

                Both A & B or not specified

    15522

    999 (6)

    847 (85)

    132 (13)

    20 (2)

    27607

    5208 (19)

    3982 (76)

    1207 (23)

    19 (1)

    42623

    6095 (14)

    4985 (82)

    1060 (17)

    50 (1)

    62128

    11347 (18)       

    8997 (79)

    2265 (20)

    85 (1)

    Antiviral Prescribed

          Inpatient

          Outpatient

          Positive influenza test

    3634

    920

    2714

    648 (18)

    20986

    6174

    14812

    3660 (17)

    16758

    4303

    12455

    4606 (27)

    32044

    7423

    24621

    8551 (27)

    Conclusion: Compared to previous seasons, increases in hospitalizations, deaths, influenza testing and antiviral prescriptions were observed in the 2014-15 influenza season.  Strain characterization demonstrated heterogeneity of HA epitopes compared to vaccine strains.

    Figure 1.  Comparison of Key VA Influenza Indicators, by Season

    Figure 2.  Variability in VA Influenza Hemagglutinin (HA) Epitopes from 10 Facilities, 2014-15 Season

     

    Patricia Schirmer, MD1, Cynthia Lucero-Obusan, MD1, Mark Winters, MS2,3, Russell Ryono, Pharm. D.1, Gina Oda, MS1 and Mark Holodniy, MD, FIDSA, FSHEA1,2, (1)Office of Public Health, Department of Veterans Affairs, Washington, DC, (2)Stanford University, Palo Alto, CA, (3)VA Palo Alto Health Care System, Palo Alto, CA

    Disclosures:

    P. Schirmer, None

    C. Lucero-Obusan, None

    M. Winters, None

    R. Ryono, None

    G. Oda, None

    M. Holodniy, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.