This review describes the eosinophil journey through the various physiological and pathophysiological phases, from production, maturation, and activation by chemokines and cytokines [especially eotaxin, interleukin (IL)-5, IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF)], to interaction with the innate and adaptive immune system and tissue homing. Excessive production and activation of eosinophils lead to the release of granule proteins, such as major basic protein, eosinophil cationic protein, eosinophil peroxidase, and others, resulting in inflammation, cell cytotoxicity, and oxidative stress. The pathogenesis, clinical features, diagnostic processes, and the latest therapeutic approaches to the resulting diseases—which affect the upper and lower airways, gastrointestinal tract, skin, myocardium, and may occur systemically—are discussed.

Aim: Despite the revolutionary impact of biologics (Bx) on severe asthma management, predicting individual treatment responses remains challenging. We aimed to characterize the heterogeneous nature of clinical status and disease activity in patients with severe asthma after biologic therapies through a comprehensive evaluation of real-world clinical outcomes. Methods: In this retrospective, multicenter study of 53 patients with severe asthma who received biologic therapies, hierarchical clustering analysis was performed based on three key parameters during treatment: exacerbation, maintenance oral corticosteroid (mOCS) dose, and lung function. Canonical correlation analysis and multinomial logistic regression were used to identify predictors of response patterns. Results: Clustering analysis revealed three distinct control groups: well-controlled (n = 23), moderately controlled (n = 22), and poorly controlled (n = 8). Well-controlled patients exhibited minimal exacerbations, no oral corticosteroid (OCS) use, and optimal or stabilized lung function. Moderately controlled patients showed minimal exacerbations and no mOCS use but variable lung function improvements. Poorly controlled patients exhibited persistent exacerbations, mOCS dependence, or both with limited lung function improvement. Baseline forced expiratory volume in 1 second (FEV1) %predicted (percent predicted FEV1) values and blood eosinophil counts independently differentiated well-controlled from moderately controlled patients, whereas baseline mOCS use distinguished moderately controlled from poorly controlled patients. Conclusions: Our findings reveal distinct patterns of disease control following biologic therapy in severe asthma, with baseline lung function, eosinophilic inflammation, and OCS use as key predictive factors. These results support the need for personalized treatment approaches in severe asthma management.

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection (LRTI) burden among infants. Maternal vaccination is a promising preventive strategy, conferring passive immunity through transplacental antibody transfer. The current narrative review was conducted to summarize the current evidence of efficacy and safety of maternal RSV vaccination and assess the practical barriers to its implementation. This review was based on a structured literature search of PubMed/MEDLINE and Google Scholar to identify peer-reviewed studies published between January 2022 and March 2025 using terms such as “maternal RSV vaccine”, “efficacy”, “safety”, “pregnancy”, “Abrysvo”, and “hesitancy”. The review included 5 clinical trials evaluating maternal RSV vaccines and 17 observational and survey studies assessing vaccine acceptance across diverse settings. The bivalent RSVpreF vaccine (Abrysvo) is the only licensed maternal RSV vaccine as of May 2025. In the MATISSE phase 3 trial (n = 7,358), the vaccine demonstrated 81.8% efficacy against medically attended RSV-LRTI at 90 days and 69.4% at 180 days, with 57.1% efficacy against severe RSV-LRTI. No major safety concerns were identified; adverse events and preterm birth rates were comparable between groups. In contrast, trials of GSK’s RSVPreF3-Mat vaccine revealed higher rates of preterm birth (6.8% vs. 4.9%) and a numerical imbalance in infant deaths (0.4% vs. 0.2%), prompting early termination. Across 17 studies (n = 14,959), RSV vaccine acceptance ranged from 39% (France) to 87% (Netherlands), with safety concerns and cultural context influencing attitudes. This review highlights that maternal RSV vaccination with RSVpreF offers effective infant protection with an acceptable safety profile. Future research should focus on long-term infant outcomes, comparative effectiveness in diverse settings, and next-generation vaccines. Implementation will require public trust, cultural sensitivity, and equitable global access.