Nirsevimab and Hospitalization for RSV Bronchiolitis.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis, resulting in 3 million hospitalizations each year worldwide. Nirsevimab is a monoclonal antibody against RSV that has an extended half-life. Its postlicensure real-world effectiveness against RSV-associated bronchiolitis is unclear. METHODS: We conducted a prospective, multicenter, matched case-control study to analyze the effectiveness of nirsevimab therapy against hospitalization for RSV-associated bronchiolitis in infants younger than 12 months of age. Case patients were infants younger than 12 months of age who were hospitalized for RSV-associated bronchiolitis between October 15 and December 10, 2023. Control patients were infants with clinical visits to the same hospitals for conditions unrelated to RSV infection. Case patients were matched to control patients in a 2:1 ratio on the basis of age, date of hospital visit, and study center. We calculated the effectiveness of nirsevimab therapy against hospitalization for RSV-associated bronchiolitis (primary outcome) by means of a multivariate conditional logistic-regression model with adjustment for confounders. Several sensitivity analyses were performed. RESULTS: The study included 1035 infants, of whom 690 were case patients (median age, 3.1 months; interquartile range, 1.8 to 5.3) and 345 were matched control patients (median age, 3.4 months; interquartile range, 1.6 to 5.6). Overall, 60 case patients (8.7%) and 97 control patients (28.1%) had received nirsevimab previously. The estimated adjusted effectiveness of nirsevimab therapy against hospitalization for RSV-associated bronchiolitis was 83.0% (95% confidence interval [CI], 73.4 to 89.2). Sensitivity analyses gave results similar to those of the primary analysis. The effectiveness of nirsevimab therapy against RSV-associated bronchiolitis resulting in critical care was 69.6% (95% CI, 42.9 to 83.8) (27 of 193 case patients [14.0%] vs. 47 of 146 matched control patients [32.2%]) and against RSV-associated bronchiolitis resulting in ventilatory support was 67.2% (95% CI, 38.6 to 82.5) (27 of 189 case patients [14.3%] vs. 46 of 151 matched control patients [30.5%]). CONCLUSIONS: In a real-world setting, nirsevimab therapy was effective in reducing the risk of hospitalized RSV-associated bronchiolitis. (Funded by the National Agency for AIDS Research-Emerging Infectious Disease and others; ENVIE ClinicalTrials.gov number, NCT06030505.).

Extra-osseous manifestations in chronic recurrent multifocal osteomyelitis: a retrospective study.

OBJECTIVES: Extra-osseous (EO) manifestations are poorly characterized in chronic recurrent multifocal osteomyelitis (CRMO). This study aimed to further define the frequency, characteristics and treatment of EO events in CRMO and whether different phenotypes can be distinguished and benefit from special management. METHODS: This multicentre retrospective study included CRMO patients followed in several paediatric rheumatology departments in France, between 2015 and 2022. EO manifestations were defined as skin lesions, gastrointestinal manifestations, arthritis, enthesitis, sacroiliitis, uveitis, vasculitis, and fever. At the last visit, the physician defined CRMO as active in the presence of clinical manifestations including both osseous and EO symptoms. RESULTS: We included 133 patients; 87 (65.4%) were girls; the median age at first symptoms was 9.0 years (interquartile range 7.0-10.0). EO manifestations were described in 90 (67.7%) patients, with a predominance of skin lesions (n = 51/90; 56.7%), followed by sacroiliitis (n = 38/90; 42.2%), enthesitis (n = 21/90; 23.3%), arthritis (n = 14/90, 15.6%) and gastrointestinal manifestations (n = 6/90, 6.7%). The use of non-steroidal anti-inflammatory drugs and bisphosphonates did not differ by presence or not of EO manifestations. Biologics were taken more frequently by patients with than without EO manifestations (p< 0.001); tumour necrosis factor inhibitors were used in 33 (36.7%) EO+ patients. Under this treatment, 18 (54.5%) patients achieved complete remission of osseous and EO manifestations. At the last visit, more EO-positive than EO-negative patients were on treatment (p= 0.009), with active disease in 58 (64.4%) patients. CONCLUSION: The analysis of EO manifestations in CRMO delineates 2 groups of patients in terms of severity and treatments used. Our study opens up new pathophysiological leads that may underlie the wide range of CRMO phenotypes.