78. Acute Respiratory Illnesses in Children During the sars-cov-2 Pandemic: A Prospective Multicenter Surveillance Study

BACKGROUND: A state of emergency was declared in the United States (US) on March 13, 2020 in response to the SARS-CoV-2 pandemic. Healthcare providers had to alter practice patterns and research priorities. We assessed the frequency of acute respiratory illnesses (ARI) in children, notably those due to respiratory syncytial virus (RSV) and influenza, before and during the pandemic. METHODS: We conducted multi-center active prospective ARI surveillance in children as part of the New Vaccine Surveillance Network. Children < 18 years with fever and/or respiratory symptoms were enrolled in emergency department and inpatient settings at seven US medical centers over four respiratory seasons during 2016–2020 (Fig 1). Pandemic-related restrictions to patient access limited enrollment in some sites beginning March 2020. Respiratory specimens were collected and tested at each site for RSV and influenza by qRT-PCR. Data were analyzed by calendar weeks. We compared the cumulative proportions of RSV and influenza detection after week 13 in 2020 to the previous seasons using Fisher’s exact test. Figure 1. Numbers of Eligible and Enrolled Acute Respiratory Illness Cases, and Proportions of RSV and Influenza Detection by Week, Stratified by Study Season [Image: see text] RESULTS: Of 44,247 eligible children, 25,375 (57%) were enrolled and tested for RSV and/or influenza. A total of 6351/25375 (25%) and 3446/25372 (14%) children were RSV and influenza-positive over the four seasons, respectively. In 2020, we noted a rapid drop in eligible and enrolled ARI subjects after weeks 11–13 (Fig 1). During weeks 13–18 in 2016–2019, the three-year average of eligible and enrolled subjects was 1802 and 978, respectively. However, over the same period in 2020, there were 675 eligible and 278 enrolled subjects, representing declines of 62.5% and 71.6% respectively (Fig 1). In 2020, there were no RSV or influenza cases detected in weeks 15–18, and the cumulative proportions of RSV and influenza detection after week 13 were lower compared to previous seasons (p< 0.001) (Figs 1 and 2). Figure 2. Cumulative Proportions of Weekly RSV and Influenza Detection by Study Season [Image: see text] CONCLUSION: There was a considerable decline in ARI visits and the proportion of RSV and influenza detection across seven distinct geographic sites during the pandemic compared with previous seasons. These findings might be attributable to social distancing measures to lessen the spread of SARS-CoV-2, changes in healthcare-seeking behaviors, and limited access to medical care. DISCLOSURES: Zaid Haddadin, MD, CDC (Grant/Research Support, Research Grant or Support)Quidel Corporation (Grant/Research Support, Research Grant or Support)sanofi pasteur (Grant/Research Support, Research Grant or Support) John V. Williams, MD, GlaxoSmithKline (Advisor or Review Panel member)IDConnect (Advisor or Review Panel member)Quidel (Advisor or Review Panel member) Christopher J. Harrison, MD, GSK (Grant/Research Support, Infant menigiciccal B conjugate vaccine trial)Merck (Research Grant or Support, Infant pneumococcal conjugate vaccine trial) Janet A. Englund, MD, AstraZeneca (Scientific Research Study Investigator)GSK group of companies (Scientific Research Study Investigator)Meissa vaccines (Consultant)Merck (Scientific Research Study Investigator)Sanofi Pasteur (Consultant) Natasha B. Halasa, MD, MPH, Genentech (Other Financial or Material Support, I receive an honorarium for lectures - it’s a education grant, supported by genetech)Karius (Consultant)Moderna (Consultant)Quidel (Grant/Research Support, Research Grant or Support)Sanofi (Grant/Research Support, Research Grant or Support)