Early Estimate of Nirsevimab Effectiveness for Prevention of Respiratory Syncytial Virus-Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season - New Vaccine Surveillance Network, October 2023-February 2024.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among infants in the United States. In August 2023, CDC's Advisory Committee on Immunization Practices recommended nirsevimab, a long-acting monoclonal antibody, for infants aged <8 months to protect against RSV-associated lower respiratory tract infection during their first RSV season and for children aged 8-19 months at increased risk for severe RSV disease. In phase 3 clinical trials, nirsevimab efficacy against RSV-associated lower respiratory tract infection with hospitalization was 81% (95% CI = 62%-90%) through 150 days after receipt; post-introduction effectiveness has not been assessed in the United States. In this analysis, the New Vaccine Surveillance Network evaluated nirsevimab effectiveness against RSV-associated hospitalization among infants in their first RSV season during October 1, 2023-February 29, 2024. Among 699 infants hospitalized with acute respiratory illness, 59 (8%) received nirsevimab ≥7 days before symptom onset. Nirsevimab effectiveness was 90% (95% CI = 75%-96%) against RSV-associated hospitalization with a median time from receipt to symptom onset of 45 days (IQR = 19-76 days). The number of infants who received nirsevimab was too low to stratify by duration from receipt; however, nirsevimab effectiveness is expected to decrease with increasing time after receipt because of antibody decay. Although nirsevimab uptake and the interval from receipt of nirsevimab were limited in this analysis, this early estimate supports the current nirsevimab recommendation for the prevention of severe RSV disease in infants. Infants should be protected by maternal RSV vaccination or infant receipt of nirsevimab.

Adverse Events of Antibiotics Used to Treat Acute Otitis Media in Children: A Systematic Meta-Analysis.

OBJECTIVE: To characterize the incidence of adverse events (AEs) associated with antibiotics used to treat acute otitis media in children. STUDY DESIGN: We searched MEDLINE for studies conducted between January 1, 1966, and August 25, 2018. Two authors independently assessed potential studies and extracted the data. We included published randomized controlled trials, cross-sectional studies, and cohort studies that evaluated the incidence of diarrhea, generalized rash, diaper rash, and candidal diaper dermatitis associated with the use of amoxicillin, amoxicillin/clavulanate, azithromycin, cefdinir, and placebo in children with acute otitis media. RESULTS: We included 82 studies in the meta-analysis. The incidence of diarrhea, listed from lowest to highest, was azithromycin (2.2%), placebo (6.9%), low-dose amoxicillin (8.7%), cefdinir (13.0%), high-dose amoxicillin (13.8%), and high-dose amoxicillin/clavulanate (18.9%). The incidence of generalized rash, listed from lowest to highest, was azithromycin (1.4%), placebo (2.3%), low-dose amoxicillin (2.9%), high-dose amoxicillin/clavulanate (4.9%), and high-dose amoxicillin (6.5%). In studies of low-dose amoxicillin, we found a higher incidence of diarrhea in studies that used daily diaries to collect information about diarrhea and a lower incidence of generalized rash in studies that reported only rashes judged to be secondary to antibiotic use. CONCLUSIONS: The incidence of AEs varies widely depending on which antibiotic is used and how the information on AEs was collected or reported. The AEs rates reported here may be helpful to clinicians when choosing an antibiotic to treat acute otitis media.