Assessing Clinical Improvement of Infants Hospitalized for Respiratory Syncytial Virus–Related Critical Illness
Authors: Leland Shannon B , Zambrano Laura D , Staffa Steven J , McNamara Elizabeth R , Newhams Margaret M , Halasa Natasha , Amarin Justin Z , Stewart Laura S , Shein Steven L , Carroll Christopher L , Fitzgerald Julie C , Michaels Marian G , Bline Katherine , Cullimore Melissa L , Loftis Laura , Montgomery Vicki L , Jeyapalan Asumthia S , Pannaraj Pia S , Schwarz Adam J , Cvijanovich Natalie Z , Zinter Matt S , Maddux Aline B , Bembea Melania M , Irby Katherine , Zerr Danielle M , Kuebler Joseph D , Babbitt Christopher J , Gaspers Mary G , Nofziger Ryan , Kong Michele , Coates Bria M , Schuster Jennifer E , Gertz Shira J , Mack Elizabeth H , White Benjamin R , Harvey Helen , Hobbs Charlotte V , Dapul Heda , Butler Andrew D , Bradford Tamara T , Rowan Courtney M , Wellnitz Kari , Staat Mary Allen , Aguiar Cassyanne L , Hymes Saul R , Campbell Angela P , Randolph Adrienne G ,   Respiratory Syncytial Virus - Pediatric Intensive Care (RSV-PIC) Investigators, Tomcany Merry , Michelson Kelly N , Price Heather E , Sanders Ronald C , Dixon Lexie , Typpo Katri V , Harwayne-Gidansky Ilana , Kucukak Suden , Chen SabrinaR , Listerud Eve , Vargas-Shiraishi Ofelia , Oberle Betty , Zorensky Frances , Mansour Rachel , Jumarang Jaycee , Johnston Marla , Bush Jenny L , Dickey Shawn , Hill Shannon , Sullivan Melissa , Kietzman Abigail , Colston Candice , Murdock Meghan , Kelley Heather , Wright-Sexton Laura , Martin Maygan , Martin Lora , Malloch Lacy , Patterson Kayla , Sanders Cameron , Rohlfs Chelsea , Rice Marilyn , Howard Miranda , Murphy Makayla , Soma Vijaya L , Ratner Adam J , Job Megan J , Mennie Colleen , Simkhada Kamala , Betters Kristina A , Hayek Haya , Maranto Molly , Waters Aubrie , Flowers Maggie , Havlin Kevin , Furlong-Dillard Jamie , Porter Melissa , Nason Jennifer , Ray Madison , Gossett Kristen , Crandall Hillary , Heller Evan , Foley Jennifer , Rasal Rajashri , Marlow Christine , Senthil Anurithi , Myers Kimberly , Tudor Betsy , Adler Amanda , Garcia Nereyda , Treister Natalie , McQuillen Patrick S , Sun Kathleen , Villarreal-Chico Denise , Kainaroi Sophia , Williams John V 
Published: January 2025

Abstract

Background
Pediatric respiratory syncytial virus (RSV)–related acute lower respiratory tract infection (LRTI) commonly requires hospitalization. The Clinical Progression Scale–Pediatrics (CPS-Ped) measures level of respiratory support and degree of hypoxia across a range of disease severity, but it has not been applied in infants hospitalized with severe RSV-LRTI.

Methods
We analyzed data from a prospective surveillance registry of infants hospitalized for RSV-related complications across 39 pediatric intensive care units in the United States from October through December 2022. We assigned CPS-Ped (0 = discharged home at respiratory baseline to 8 = death) at admission and days 2–7, 10, and 14. We identified predictors of clinical improvement (CPS-Ped ≤2 or 3-point decrease) by day 7 using multivariable log-binomial regression models and estimated the sample size (80% power) to detect 15% between-group clinical improvement with CPS-Ped versus hospital length of stay (LOS).

Results
Of 585 hospitalized infants, 138 (23.6%) received invasive mechanical ventilation (IMV) and 1 died. Failure to clinically improve by day 7 occurred in 205 (35%) infants and was associated with age &lt;3 months, prematurity, underlying respiratory condition, and IMV in the first 24 hours in the multivariable analysis. The estimated sample size per arm required for detecting a 15% clinical improvement in a potential study was 584 using CPS-Ped clinical improvement versus 2031 for hospital LOS.

Conclusions
CPS-Ped can be used to capture a range of disease severity and track clinical improvement in infants who develop RSV-related critical illness and could be useful for evaluating therapeutic interventions for RSV.