S840 • OFID 2020:7 (Suppl 1) • Poster Abstracts Figure 1 Table 1 Table 2 Conclusion: Although infuenza-related hospitalization rates decreased with increasing age, severe outcomes were more common among hospitalized older chil- dren. Room for improvement exists in infuenza vaccination coverage and antiviral use. While 20% of children were admitted to ICU, death was uncommon. Disclosures. Sue Kim, MPH, Council of State and Territorial Epidemiologists (CSTE) (Grant/Research Support) Melissa Sutton, MD, MPH, CDC funding (Emerging Infections Program) (Grant/Research Support) Evan J. Anderson, MD, Sanof Pasteur (Scientifc Research Study Investigator) 1713. Factors Associated with Viral Rebound post Blip in Patients from a Community HIV Clinic Eduardo Sanchez, MD 1 ; Jody Borgman, MD 1 ; Aviva Jofe, MSW, LSW 1 ; Catherine Holdsworth, PhD, CRNP 1 ; 1 Albert Einstein Medical Center, Philadelphia, PA Session: P-75. Virology: Studies of the Epidemiology of Viral Infections Background. Blips are detectable increases in the HIV viral load (VL) that occur afer therapy has efectively suppressed the virus to an undetectable level. Tere is no clear etiology for the development of blips. Te association between blips and viral failure remains unclear. Methods. Tis retrospective chart review aimed to clinically characterize patients who developed blips in a community HIV clinic in north Philadelphia between 2014- 2018. A blip was defned as a single detectable VL < 500 copies/mL which appears between two undetectable VL measurements. Multivariate analysis was performed to examine the relationship of certain variables and viral rebound (VR) in patients with blips. Viral rebound was defned as post blip VL > 200 copies/mL that was not followed by an undetectable viral load. Results. Of a total of 666 patients, 225 (33.7%) had at least 1 blip. 59% were male and 41% were female. Te majority were African American (84.4%). Sixty seven per- cent were heterosexuals and 25.7% were MSM. Analyzing CD4 counts at the moment of blip, 68% had >500 cells/mm3. Te average value of the blips was 85 copies/mL with 48.8% of the patients having a blip between 20-50 copies/mL. Most of the patients were on INSTIs (49.5%) followed by NNRTIs (35.6%). Of the 225 patients, 148 had at least 1 year of follow up post-blip. Tose who were followed for less than 1-year post-blip were not included in the statistical analysis to fnd potential factors associated with VR. Tirty-two (21.6%) patients developed rebound. Te multivariate analysis showed that being male and having a higher blip value were factors associated to increased likelihood of VR. Factors associated to decreased likelihood of rebound were the use of NNRTIs at blip and an HIV transmission factor that was not heterosexual sex (MSM and IDU). All of these associations were noted to be statistically signifcant. Conclusion. Te variables that were found to be associated to viral rebound could help guide clinicians during the surveillance of patient’s with blips. Further research in larger cohorts would help clarify the role of these variables in patients who develop treatment failure. Disclosures. All Authors: No reported disclosures 1714. Influenza C Virus in U.S. Children with Acute Respiratory Infection 2016-2019 Bethany K. Sederdahl, n/a 1 ; Geofrey A. Weinberg, MD 2 ; Angela P. Campbell, MD, MPH 3 ; Rangaraj Selvarangan, BVSc, PhD 4 ; Jennifer E. Schuster, MD 4 ; Christopher J. Harrison, MD 5 ; Brian Rha, MD, MSPH 3 ; Joana Y. Lively, MPH 3 ; Manish Patel, MD 3 ; Bo Shu, MD 6 ; Julie A. Boom, MD 7 ; Vasanthi Avadhanula, PhD 8 ; Natasha B. Halasa, MD, MPH 9 ; Laura S. Stewart, PhD 9 ; Peter G. Szilagyi, MD, MPH 10 ; Robert Hickey, MD 11 ; Marian G. Michaels, MD, MPH 12 ; John V. Williams, MD 1 ; 1 University of Pittsburgh, Pittsburgh, Pennsylvania; 2 University of Rochester, Rochester, New York 3 Centers for Disease Control and Prevention, Atlanta, Georgia; 4 Children’s Mercy Hospital, Kansas City, Missouri; 5 Te Children’s Mercy Hospital- Kansas City, Kansas City, Missouri; 6 CDC, Atlanta, Georgia; 7 Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas; 8 Baylor college of medi- cine, Houston, TX; 9 Vanderbilt University Medical Center, Nashville, Tennessee; 10 University of California, Los Angeles, Los Angeles, California; 11 Childrens Hospital of Pittsburgh, Pittsburgh, Pennsylvania; 12 UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania Session: P-75. Virology: Studies of the Epidemiology of Viral Infections Background. Infuenza C virus (ICV) is associated with acute respiratory infec- tion (ARI); however, the burden of ICV is not well-described. We sought to determine the burden and characteristics of ICV in a prospective, population-based cohort. Methods. Te study was conducted within the New Vaccine Surveillance Network (NVSN), a CDC-led, seven-site network that performs population-based sur- veillance for ARI in children < 5 years. Nasal/throat swabs were collected from emer- gency department (ED) or inpatient children with ARI, or healthy controls in clinic, between 12/05/2016-10/31/2019 and tested by real-time RT-PCR for ICV and other respiratory viruses. Preliminary data were extracted and demographic/clinical features of ICV+ cases analyzed. We sequenced the hemagglutinin-esterase (HE) gene from ICV+ Pittsburgh samples. Results. Among 19,321 children with ARI or healthy controls enrolled and tested for ICV from 2016-2019, 115/17,668 (0.7%) ARI cases and 8/1653 (0.5%) healthy controls tested positive for ICV. Te median age of ICV+ ARI subjects was 19 months (IQR 10,46) and 81(70%) were ≤36 months. 42.6% (49) were white, 33.9% (39) black, and 16.5% (19) Hispanic, with the remainder Asian or unknown; 56.5% (62) attended daycare. Among ICV+ ARI cases, 67.8% (78) had fever, 94.8% (109) cough, and 60.8% (70) wheezing. 45.2% (52) ICV+ cases occurred in 2016-17, 6.5% (8) in 2017-2018, and 47.8% (55) in 2018-19 (Table). 40% (46) of ICV+ cases were seen in the ED, while the remainder were inpatients. Median length of stay was 2d (IQR,1-3) with 15 admitted to ICU. 67.8% (78/115) ARI cases had 1 or 2 co-detected pathogens, with rhinovirus (26), respiratory syncytial virus (26), and adenovirus (14) most frequently co-detected. ARI symptoms including fever, myalgias, chills, and wheezing did not difer signifcantly between coinfected subjects and those who were only ICV+. HE sequences were in the two currently circulating Kanagawa and Sao Paulo lineages. Downloaded from https://academic.oup.com/ofid/article/7/Supplement_1/S840/6058344 by guest on 19 March 2021