Most US Infants With RSV Were Healthy, Born at Term, Study Finds

Newborns that were healthy and born at term in the United States made up the majority of infants who needed intensive care for respiratory syncytial virus (RSV) lower respiratory tract infections (LRTIs), according to a new study published in JAMA Network Open. The findings suggest RSV prevention strategies should be employed for all infants, the authors concluded.

RSV is the leading cause of hospitalizations related to respiratory illness in young children globally. Palivizumab can be used monthly to prevent LRTI due to RSV, which can help protect high-risk and healthy infants from RSV. However, identifying who needs these treatments is imperative to their effectiveness. There was a surge in hospitalizations for RSV in the post-pandemic period, and specifically in fall of 2022. This study aimed to characterize the US infants who required intensive care for RSV during this period.

There were 39 pediatric hospitals covering 27 states that were used for this study. Data came from 2 months at the end of 2022, specifically from October 17 to December 16. The first 15 to 20 consecutive infants of each participating site were included to ensure there was representation from all geographic regions.

Infants were included in the RSV Pediatric Intensive Care registry if they were admitted to the intensive care unit (ICU) for 24 hours or more for RSV-related illness, had a symptom onset of less than 10 days prior to hospitalization, and had laboratory-confirmed RSV within 72 hours of hospitalization. Infants were excluded from the study if they had previously been in the RSV Pediatric Intensive Care registry or were newborns that were never discharged.

There were 600 infants included in the study. The infants had a median (IQR) age of 2.6 (1.4-6.0) months, and 60% were male. A total of 29% of the infants were born prematurely and approximately one-quarter were intubated; 81% were born healthy. A total of 99% of the infants were admitted to the hospital for LRTI but infants who were intubated had a higher frequency of apnea or bradycardia.

There were 572 (95.3%) infants who needed oxygen at admission and 143 (24%) infants who needed invasive mechanical ventilation for a median of 6.0 (4.0-10) days; 101 (70.6%) of the infants intubated were younger than 3 months. The median length of hospital stay was 5 (4-10) days. Infants who were younger than 3 months had higher disease severity scores and had longer stays in the ICU and hospital when compared with other infants.

Infants younger than 3 months had a higher risk of intubation compared with infants aged 6 to 11 months old, those born prematurely, and infants who had public insurance. There were 128 children (21.3%) who had received a positive test for at least 1 other non-RSV respiratory virus, with 19 and 7 children getting positive results for COVID-19 and influenza respectively.

The study has some limitations. The cohort only represents the first 15 to 20 consecutive RSV cases for each hospital included, so all severe RSV cases were not included in the study. Only laboratory-confirmed cases of RSV were included, which may have led to missing some cases. Disease severity could not be assessed through the influence of viral codetection. Not all infants who needed intubation were tested for bacterial coinfection, so the role of coinfection could be underestimated. Infants who were in the ICU for less than 24 hours were also excluded, which could bias the study toward the most severe RSV infections.

RSV was found to cause significant morbidity in healthy term infants as well as infants who were born prematurely. Prevention strategies, the researchers concluded, are needed for all infants to reduce the rate of severe RSV.

Reference

Halasa N, Zambrano LD, Amarin JZ, et al. Infants admitted to US intensive care units for RSV infection during the 2022 seasonal peak. JAMA Netw Open. 2023;6(8):e2328950. doi:10.1001/jamanetworkopen.2023.28950