176. Selected Impact of the 13-valent Pneumococcal Conjugate Vaccine (PCV13) on Invasive Pneumococcal Disease (IPD) at Eight Children’s Hospitals in the United States. 2014–2019

BACKGROUND: The 2011 IDSA/PIDS Clinical Practice Guidelines for the Management of Community-acquired Pneumonia (CAP) in Children Older than 3 months recommended empiric treatment with either ampicillin/penicillin or ceftriaxone based on PCV13 vaccine status and the local antibiotic susceptibilities of IPD isolates. No study has addressed differences in antibiotic susceptibilities for isolates from children with pneumococcal pneumonia (PP) based on PCV13 status. METHODS: Investigators from 8 US children’s hospitals identified infants and children with IPD between 1/1/2014 and 12/31/2019. IPD was documented by positive cultures from a normally sterile site. PP diagnosis required an abnormal chest radiograph. Clinical data were recorded and isolates analyzed for serotype (ST) by the capsular swelling method and antimicrobial susceptibilities by standard methods. Administration of PCV7/13 was documented through the patient’s medical records, health care provider or a vaccine registry. Fisher Exact was performed; p< 0.05 was significant. RESULTS: 690 IPD patients with isolates were available (0–18 y); 24% (166/690) of the isolates were PCV13 STs (ST3-75, ST19F-45, ST19A-36, ST7F-5, other STs-5). The most common non-PCV13 ST isolates were ST35B-60, ST23B-59, ST33F-47, ST22F-43, ST15C-35, ST23A-27, ST15B-26, ST10A-26, ST15A-23. Of non-PCV13 isolates, 41% (217/524) were among the 7 additional STs in PCV20. For children with PP (n=157), the distributions of penicillin (Table) (p=0.8) and ceftriaxone MICs were no different for isolates obtained from children regardless of prior PCV13 doses. Less than 7% of PP isolates were resistant to penicillin (MIC >2 µg/mL). Table. Minimal inhibitory concentrations (MIC) of pneumococcal isolates related to the number of PCV13 doses each patient received prior to pneumococcal pneumonia (PP). Number of PCV13 doses CONCLUSION: PCV13 status should not modify empiric antibiotics for children with suspected pneumococcal CAP. 41% of non-PCV13 IPD isolates were among the 7 additional PCV20 STs. DISCLOSURES: Sheldon L. Kaplan, MD, Allergan (Research Grant or Support)Pfizer (Grant/Research Support) Tina Q. Tan, MD, Pfizer (Grant/Research Support, Other Financial or Material Support, Chair, DMSB for PCV20 vaccine) Pia S. Pannaraj, MD, MPH, AstraZeneca (Grant/Research Support)Pfizer (Grant/Research Support)Sanofi Pasteur (Advisor or Review Panel member)