Mycoplasma pneumoniae – The Return after The Pandemic and Its New Alliance with Rhinovirus

Background: Mycoplasma pneumoniae (MPP) infections typically recur every 1–3 years. A new wave was expected in late 2022/early 2023, but surveillance at the Hauner Children’s Hospital revealed a delayed surge in 2023/24. Objective and Aim: To characterize pediatric MPP cases in 2023/24 compared to 2017–2022, and to assess the clinical impact of Rhino-/Enterovirus (R/EV) coinfections. Methods: We retrospectively analyzed direct MPP detections from 2017–2024. Group 1 (G1, n=10; 2017–2022) was compared with Group 2 (G2, n=87; 2023–2024). A sub-study contrasted sole MPP infections ( MMP N ) with MPP plus R/EV coinfections (MPP RV ). Statistical analyses included Chi-square/Fisher’s exact for categorical and t-test/Mann–Whitney U for continuous variables. Results: From 2017–2022, only 10 sporadic cases were identified, whereas 87 children presented in 2023/24, marking a sharp rise in hospitalizations. Demographics and clinical features did not differ significantly between groups. Coinfections were frequent (>50% in both), with bacterial coinfections predominating in G1 (30.0% vs 2.3%; P=.007) and viral coinfections, particularly R/EV, more common in G2 (20.0% vs 36.8%; P=0.183). MPP RV cases occurred mainly in young males, with reduced fever incidence (78.6% vs 50.0%; P=.017) and attenuated inflammatory markers (lower CRP, leukocytes, neutrophils), consistent with a viral-driven immune response. Conclusion: In 2023/24, MPP infections resurged dramatically, accompanied by unprecedented R/EV coinfections. Both pathogens appear to exert a distinct impact on the immune response. The long-term consequences of a potential double-hit synergy warrant further investigation and should be prioritized in future research. Publication History Article published online: 26 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany