932. Characterization of Patients Infected with Influenza B Viruses with a Novel I221V Neuraminidase Mutation  
Session: Poster Abstract Session: Biomarkers and Risk Factors for Viral Infections
Saturday, October 22, 2011
Room: Poster Hall B1
  • I221V_IDSA_Poster.pdf (348.3 kB)
  • Background: During the 2010–2011 season, influenza B viruses collected in North Carolina (NC) through routine surveillance were found to have a novel I221V mutation (I221V) in the neuraminidase (NA) associated with reduced susceptibility to oseltamivir by NA inhibition assay (NI).  We determined the extent of I221V B virus circulation, investigated whether I221V arose during oseltamivir use, and compared characteristics of patients infected with B viruses with and without I221V.

    Methods: All B viruses identified by the NC State Laboratory of Public Health during November 2010–March 2011 were pyrosequenced to look for I221V.  B viruses submitted to the Centers for Disease Control and Prevention from other states were tested by NI and/or pyrosequencing for I221V.  We conducted standardized medical record reviews and phone interviews to collect data from all NC patients for whom pyrosequencing results were available.

    Results: In NC, I221V was detected in 45 (22%) of 209 patients with B virus infections from 41 (41%) of 100 counties. Patients with I221V B virus infections resided in 11 (27%) counties, and 56% were from three contiguous counties near Charlotte, NC.  In South Carolina (SC), six (12.5%) of 48 patients with B virus infections had I221V; five were from one county adjacent to Charlotte, NC.  No B viruses tested from 34 other states (n=326) had I221V. Medical records were available for 190 patients (91%) from NC, including 39 (21%) with I221V.  The presence of I221V was not significantly associated with differences in age, underlying medical conditions, hospitalizations or deaths. No patients with I221V B virus infection had received oseltamivir prior to specimen collection.  Among 149 patients (71%) who completed a phone survey, the presence of I221V was not significantly associated with differences in clinical symptoms, number of days of illness or number of days of school/work missed.

    Conclusion: Influenza B viruses with an I221V mutation co-circulated with wild-type viruses in a localized region in NC and SC during the 2010–2011 season. Clinical illness from B virus infection was not impacted by the presence of I221V; however, the clinical significance of I221V on oseltamivir effectiveness is unknown.  Efforts to monitor for I221V B viruses are ongoing.

    Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

    Shikha Garg, MD, MPH1, John McKenna, BS2, Nicole Lee, MPH3, Amber Bishop, MPH4, Natalie Dailey, MD5,6, Aaron Fleischauer, PhD, MPH7, Susan Kilpatrick8, Katrina Sleeman, PhD9, Tiffany G. Sheu, 9, Chasisity B. Springs, MSPH10, Larisa Gubareva, MD, PhD11, Zack Moore, MD, MPH6 and Alicia Fry, MD, MPH11, (1) , Centers for Disease Control and Prevention, Atlanta, GA, (2)CDC Foundation, Atlanta, GA, (3)North Carolina Division of Public Health, Raleigh, NC, (4)CDC/Battelle, Atlanta, GA, (5)Epidemic Inelligence Service, CDC, Raleigh, NC, (6)NC Dept. of Health and Human Services, Raleigh, NC, (7)CDC, Raleigh, NC, (8)North Carolina State Laboratory of Public Health, Raleigh, NC, (9)CDC, Atlanta, GA, (10)SC Department of Health and Environmental Control, Columbia, SC, (11)Centers for Disease Control and Prevention, Atlanta, GA


    S. Garg, None

    J. McKenna, External Medical Affairs, Pfizer Inc.: Grant recipient through the CDC Foundation, Grant recipient

    N. Lee, None

    A. Bishop, None

    N. Dailey, None

    A. Fleischauer, None

    S. Kilpatrick, None

    K. Sleeman, None

    T. G. Sheu, None

    C. B. Springs, None

    L. Gubareva, None

    Z. Moore, None

    A. Fry, None

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