Clinical characteristics and outcomes of children with measles requiring pediatric intensive care: a multicenter study in Istanbul

Abstract Measles remains a major public health concern despite the availability of effective vaccines. Recent global resurgences, including in Türkiye, have been partly attributed to disruptions in routine immunization and declining vaccination coverage during the COVID-19 pandemic. Data on children with measles requiring pediatric intensive care are limited. We aimed to describe the clinical characteristics and outcomes of children with measles admitted to pediatric intensive care units (PICUs) in a large metropolitan area. This multicenter retrospective study included children < 18 years with laboratory-confirmed measles admitted to ten PICUs in Istanbul, Türkiye, between January and December 2023. Demographic data, vaccination status, clinical features, laboratory findings, treatments, and outcomes were collected. Patients were stratified by vaccination status. Among 5,685 PICU admissions, 53 children (median age 1.3 years) had laboratory-confirmed measles. Ten (18.9%) were vaccinated and 43 (81.1%) were unvaccinated. The median rash duration was longer in vaccinated children (3 vs. 2 days; p = 0.027). Rash onset most frequently involved the face in vaccinated children (70%), whereas trunk onset predominated in unvaccinated children (51.2%) ( p < 0.001). Unvaccinated children were admitted closer to rash onset, indicating a more rapidly evolving clinical course. Rhinorrhea was more common in unvaccinated children (69.8% vs. 20%; p = 0.009). Median oxygen saturation at PICU admission was lower in unvaccinated patients (91% vs. 95%; p = 0.015). Although ARDS, inotropic support, and invasive ventilation were more frequent in unvaccinated children, these differences were not statistically significant. In multivariable analysis, abnormal chest radiographic findings showed a trend toward association with respiratory support, although this did not reach statistical significance. Overall mortality was 2.3% (1/53), occurring in an unvaccinated infant. Conclusion : Measles continues to cause critical illness in young children requiring PICU care. Unvaccinated children tended to present with lower oxygen saturation at admission, suggesting more pronounced respiratory involvement. Maintaining high vaccination coverage remains essential to reduce severe measles-related morbidity. What is Known: • Measles outbreaks persist in areas with suboptimal vaccination coverage, with unvaccinated children at higher risk of severe complications. • Data on critically ill children with measles, particularly those requiring intensive care, remain limited. What is New: • This multicenter study provides contemporary PICU-based data from a recent measles outbreak in a large European metropolitan area, where most critically ill children were unvaccinated and very young. • Unvaccinated children showed trends toward lower oxygen saturation and more pronounced respiratory involvement, though findings should be interpreted cautiously due to the small sample size.