Respiratory Viruses Disrupt Cancer Care in Children, Italian Survey Finds

Children undergoing treatment for cancer and blood disorders face a constant, invisible threat that has little to do with their underlying malignancy: the common respiratory viruses that circulate every winter in schools, homes and clinics. A new survey of pediatric oncology and hematology centers across Italy, conducted under the umbrella of the Italian Association of Pediatric Hematology and Oncology (AIEOP), has now provided one of the clearest pictures to date of how these community-acquired respiratory virus infections, known by the acronym CARV, are diagnosed, managed and feared in this uniquely vulnerable population. The study, published in the journal Annals of Hematology, reveals a landscape in which most infections are mild, yet the ripple effects on cancer treatment are substantial and, crucially, handled very differently from one center to the next.

The research team, led by Nicoletta Abram, Davide Leardini and Federico Mercolini of the University of Bologna and the IRCCS Azienda Ospedaliero-Universitaria di Bologna, together with senior author Simone Cesaro of Verona, distributed a structured survey to pediatric onco-hematology centers throughout Italy. The questionnaire probed four main domains: the epidemiology of CARV infections in children receiving chemotherapy or hematopoietic cell transplantation, the ways in which viral episodes influenced the delivery of oncologic treatment, the use of the antiviral drug oseltamivir, and the vaccination policies adopted for patients and their household contacts. This approach reflects a growing recognition that respiratory viruses are not a peripheral nuisance in pediatric oncology but a recurring operational challenge that every center must confront, often without the benefit of shared guidelines.

Community-acquired respiratory viruses encompass a broad roster of pathogens, including influenza viruses, respiratory syncytial virus, rhinoviruses, coronaviruses, parainfluenza viruses, adenoviruses and human metapneumovirus. In immunocompetent children, these agents typically cause self-limiting upper respiratory illness. In children with leukemia, lymphoma, solid tumors or inherited hematologic disorders, however, the calculus changes dramatically. Intensive chemotherapy regimens induce prolonged neutropenia, impair both humoral and cellular immunity, and can strip away the mucosal barriers that normally contain infection. As a result, a virus that would cause a few days of sniffles in a healthy child can progress to pneumonia, require intensive care, or force the postponement of the very chemotherapy cycles that keep the malignancy in check.

The survey’s central epidemiological finding is, in many ways, reassuring: the majority of CARV infections reported by the Italian centers were mild and were managed on an outpatient basis. Most children did not require admission to hospital, and severe outcomes were not the norm. This aligns with a growing body of literature suggesting that, in the era of routine molecular diagnostics, many respiratory viral infections in pediatric cancer patients are detected early, while they are still confined to the upper airway, and resolve without invasive intervention. The widespread availability of multiplex polymerase chain reaction panels, which can identify a dozen or more respiratory pathogens from a single nasopharyngeal swab within hours, has transformed the diagnostic landscape and allows clinicians to distinguish viral from bacterial causes of fever far more rapidly than was possible a generation ago.

Yet the picture darkens considerably when the analysis turns to influenza. Among the various CARV pathogens, influenza stood out as the virus most consistently associated with hospitalization and with pneumonia, the most feared pulmonary complication in a neutropenic host. This finding carries real clinical weight. Influenza is notorious for its capacity to descend from the upper respiratory tract into the lungs, particularly in patients whose immune systems cannot mount an effective cytotoxic response, and secondary bacterial superinfection is a well-recognized hazard. The Italian data thus reinforce a message that infectious disease specialists have been repeating for years: within the population of children on active cancer treatment, influenza should be regarded not as a routine winter illness but as a pathogen with a distinctly elevated risk profile that justifies aggressive prevention and prompt antiviral therapy.

The second major theme of the survey concerns the disruption that CARV infections impose on oncologic treatment schedules. The authors report that the occurrence of a respiratory viral infection affects mainly the continuity of chemotherapy, meaning that cycles are delayed, interrupted or modified while the child recovers. For diseases such as acute lymphoblastic leukemia, where treatment intensity and timing are calibrated to disease biology, such interruptions are not trivial. Delayed chemotherapy can prolong the duration of therapy, extend periods of profound immunosuppression, and in some contexts may compromise outcomes. At the same time, administering myelosuppressive chemotherapy to a child with active viral pneumonia risks catastrophic deterioration. Clinicians are therefore forced into a delicate balancing act, weighing the oncologic cost of delay against the infectious risk of proceeding, often with limited evidence to guide them.

It is precisely here that the survey exposes its most consequential finding: marked variability in how centers respond. When faced with a CARV infection, Italian pediatric onco-hematology units differed substantially in whether and for how long they interrupted oncologic treatment, and in their thresholds for delaying chemotherapy in asymptomatic or mildly symptomatic children. Similar heterogeneity emerged in the use of oseltamivir, the neuraminidase inhibitor that remains the mainstay of influenza therapy in children. Some centers prescribed it liberally for suspected or confirmed influenza, others reserved it for severe presentations or for early treatment within the window of maximal benefit, and the survey found no consensus on dosing strategies for severely immunocompromised patients, a population in which prolonged viral shedding and the emergence of resistance are documented concerns. This patchwork of practice, the authors argue, reflects the absence of standardized, evidence-based approaches to CARV management in pediatric onco-hematology.

Vaccination policy emerged as a third area of divergence, and one with clear public health implications. The survey found that influenza vaccination was strongly recommended to household and close contacts of immunocompromised children across the participating centers, a strategy known as cocooning that builds a protective ring of immunized adults and siblings around the vulnerable patient. However, the indications for vaccinating the patients themselves varied among centers. This divergence is understandable in part: inactivated influenza vaccines are generally considered safe even in immunocompromised hosts, but their immunogenicity is blunted during intensive chemotherapy, raising questions about the optimal timing of vaccination relative to treatment phases. Live attenuated influenza vaccine, administered intranasally, is generally avoided in profoundly immunosuppressed patients. The consistency of the recommendation to vaccinate contacts, contrasted with the inconsistency of recommendations for patients, highlights an area where harmonized national or international guidance could deliver immediate benefit.

The broader significance of the AIEOP survey lies in what it says about the state of the field. The COVID-19 pandemic dramatically raised awareness of respiratory viral threats among immunocompromised populations and accelerated the adoption of molecular diagnostics, antiviral agents and infection control measures in oncology wards. Yet, as this study demonstrates, the translation of that heightened awareness into standardized clinical practice remains incomplete. The authors’ findings underscore the need for prospective, multicenter studies that can define the true incidence and severity of CARV infections in pediatric onco-hematology, establish evidence-based criteria for interrupting or continuing chemotherapy, and clarify the role of antiviral prophylaxis and treatment in this population. They also reinforce the importance of influenza vaccination, both for patients where feasible and for their close contacts, as the single most effective available intervention against the virus that the survey identified as the most dangerous of the CARV group. Until such standards are established, the experience of Italian centers offers a candid snapshot of a clinical community doing its best to navigate seasonal viruses with incomplete maps, and a compelling argument for building better ones.

Subject of Research: Community-acquired respiratory virus infections in pediatric onco-hematology patients

Article Title: Epidemiology, impact on oncologic treatments, and management of community-acquired respiratory virus (CARV) infections in pediatric onco-hematology patients: a survey among Italian pediatric oncology hematology centres (AIEOP)

Article References: Epidemiology, impact on oncologic treatments, and management of community-acquired respiratory virus (CARV) infections in pediatric onco-hematology patients: a survey among Italian pediatric oncology hematology centres (AIEOP). (n.d.). https://doi.org/10.1007/s00277-026-07175-x

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07175-x

Keywords: community-acquired respiratory viruses, pediatric oncology, hematology, influenza, oseltamivir, chemotherapy, vaccination, immunocompromised children, pneumonia, AIEOP, viral epidemiology, infection control