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

In a study published in BMC Complementary Medicine and Therapies, a team led by Fahime Edalat, Fatemeh Jahedi, Neda Pirbonyeh and Afagh Moattari of Shiraz University of Medical Sciences, working with colleagues at Tehran University of Medical Sciences, Ardakan University and Tarbiat Modares University, systematically evaluated the antiviral activity of an aqueous-alcoholic extract of Adiantum capillus-veneris against influenza A(H1N1) in cell culture. The research was conceived against a backdrop of increasing concern about antiviral resistance and a growing interest in herbal medicines that combine anti-inflammatory and antioxidant properties with potential direct antiviral effects. Although A. capillus-veneris has a long history of folk use for respiratory complaints, its potential to inhibit influenza viruses had never been rigorously tested, making the new work the first detailed in vitro characterization of its anti-influenza activity.

The team adopted a carefully staged experimental design to disentangle the different ways in which a botanical extract might interfere with viral infection. The first step was to establish the safety profile of the extract for the host cells. Using Madin-Darby Canine Kidney cells, the standard laboratory substrate for influenza research, the investigators applied the MTT assay, a colorimetric test that measures metabolic activity and therefore cell viability, to determine the 50 percent cytotoxic concentration, or CC50, of the extract. This value defines the dose at which the extract harms half of the host cells and thus sets the ceiling for any antiviral testing. The extract exhibited a CC50 of approximately 1 milligram per milliliter, a result the researchers describe as indicating moderate cytotoxicity. Armed with this safety threshold, they could then probe concentrations well below the toxic limit for genuine antiviral effects.

To explore how the extract might interact with the viral life cycle, the researchers introduced it at three distinct stages relative to infection. In the pre-treatment scenario, cells were exposed to the extract before the virus arrived, testing whether the plant preparation could prime the cellular environment or block viral attachment in some way. In the co-treatment scenario, extract and virus were applied simultaneously, probing interactions during the earliest steps of infection such as binding and entry. In the post-treatment scenario, the extract was added after viral inoculation, asking whether it could suppress replication once the virus had already gained entry to the cells. For comparison, oseltamivir was tested separately, added one hour after viral inoculation, replicating its clinical role as a post-exposure inhibitor of viral spread.

The readouts were equally comprehensive. Cytopathic effects, the visible damage that influenza inflicts on infected cell monolayers, were monitored 48 to 72 hours after inoculation. Viral titers were then quantified using three independent methods: the hemagglutination assay, which measures the ability of viral particles to agglutinate red blood cells; quantitative real-time PCR, which tracks viral RNA load; and the TCID50 assay, which calculates the tissue culture infectious dose, a functional measure of how much infectious virus remains. Together these assays provided a multi-angle view of viral burden, reducing the risk that a single methodological artifact could be mistaken for a true antiviral effect.

The results were striking. In the TCID50 assays, the extract demonstrated strong antiviral activity across concentrations ranging from 0.02 to 0.5 milligrams per milliliter, all comfortably below the cytotoxic threshold. The most impressive finding came from the pre-treatment arm: at a concentration of just 0.1 milligrams per milliliter, extract administered before infection reduced viral load by 99.9 percent, a reduction of three orders of magnitude in infectious virus. Meanwhile, at 0.5 milligrams per milliliter, the extract suppressed viral replication when applied during the infection window itself. The fact that pre-treatment produced the most dramatic suppression suggests that the extract may interfere with early events in the viral life cycle, perhaps by altering host cell surface receptors, blocking viral binding or entry, or inducing intracellular states less hospitable to the virus. The researchers caution, however, that the precise molecular stage at which the inhibition occurs remains to be determined.

Perhaps the most clinically relevant discovery, though, emerged when the extract was tested in combination with oseltamivir. When oseltamivir at concentrations of 0.5 and 0.05 milligrams per milliliter was paired with the extract at 0.5, 0.1 and 0.05 milligrams per milliliter, the combination produced a synergistic effect against influenza A(H1N1), delivering suppression that clearly surpassed what oseltamivir alone could achieve. Synergy of this kind is a significant observation for several reasons. First, it suggests that the extract and the neuraminidase inhibitor act on different aspects of the viral life cycle or on complementary molecular targets, since compounds competing for the same target typically show additive rather than synergistic effects. Second, combination approaches can lower the effective dose of each agent, potentially reducing side effects and, critically, slowing the emergence of drug-resistant viral variants, which thrive under monotherapy pressure. If the in vitro findings can be extended in animal models and eventually in clinical settings, an extract-based adjunct to standard antiviral therapy could offer a valuable hedge against oseltamivir resistance.

The biological plausibility of such effects is grounded in what is already known about Adiantum capillus-veneris. The fern, found across temperate and tropical regions, has featured in traditional medical systems as a remedy for coughs, bronchitis and other respiratory conditions. Previous phytochemical and pharmacological studies have attributed anti-inflammatory and antioxidant properties to its preparations, characteristics that could modulate the host environment in ways unfavorable to viral replication. The new study adds a direct antiviral dimension to this picture, although the authors emphasize that the specific chemical constituents responsible for the observed activity have not yet been identified. Flavonoids, phenolic acids and triterpenoids are common candidates in fern extracts, but confirming the active molecules will require bioassay-guided fractionation, a process of progressively separating and testing extract components to pinpoint the compounds carrying the antiviral punch.

The researchers are candid about the limits of their work. The experiments were conducted entirely in vitro, in a cell culture system that cannot capture the complexity of a living host, including immune responses, pharmacokinetics, metabolism and tissue distribution. The moderate cytotoxicity profile, with a CC50 close to the antiviral concentrations used, means that any future therapeutic application will require careful optimization of dose, formulation and potentially the isolation of active compounds to improve the therapeutic window. The study was performed in accordance with the Declaration of Helsinki and approved by the Ethics Committee of Shiraz University of Medical Sciences, and it was funded by Shiraz University of Medical Sciences. The authors also disclosed that they used ChatGPT for assistance with English language editing while retaining full responsibility for the scientific content, data analysis, interpretation and conclusions.

Looking forward, the research team recommends two priorities: identifying the specific active components of the extract and determining the exact stage of viral replication at which inhibition occurs. Both are essential steps on the long road from cell culture to clinic. If a discrete molecule can be isolated, characterized and shown to inhibit influenza A(H1N1) at achievable, non-toxic concentrations, it could become a lead compound for drug development or a standardized herbal medicine candidate. Even short of that, the demonstration that a traditional fern remedy can achieve a 99.9 percent reduction in viral load in pre-treated cells, and can synergize with a widely used antiviral drug, adds weight to the growing argument that ethnobotanical knowledge remains a rich and underexplored reservoir of antiviral potential. As influenza continues to mutate and evade single-target drugs, the maidenhair fern, a humble plant steeping in a laboratory beaker in Shiraz, may yet contribute something unexpected to the arsenal against one of humanity’s oldest viral adversaries.

Subject of Research: Antiviral activity of Adiantum capillus-veneris L. plant extract against influenza A(H1N1) in vitro

Article Title: Unveiling the antiviral activity of Adiantum capillus-veneris L. against influenza A(H1N1)

Article References: Edalat, F., Jahedi, F., Taghiabadi, Z., Letafati, A., Pirbonyeh, N., Pourghanbari, G., Shatizadeh Malekshahi, S., & Moattari, A. (2026). Unveiling the antiviral activity of Adiantum capillus-veneris L. against influenza A(H1N1). BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05584-z

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05584-z

Keywords: influenza A(H1N1), Adiantum capillus-veneris, antiviral activity, herbal extract, oseltamivir, TCID50, MDCK cells, real-time PCR, hemagglutination assay, cytotoxicity, synergy, natural remedies

At the molecular level, the circulating strain belongs to the family Orthomyxoviridae and carries a negative-sense, single-stranded, segmented RNA genome that encodes the structural and non-structural proteins required for its replication cycle. The two primary surface glycoproteins, hemagglutinin and neuraminidase, govern the critical steps of host cell attachment, viral entry, and release of progeny virions. Hemagglutinin binds to alpha-2,6-linked sialic acid receptors, which are abundantly expressed on human upper respiratory epithelial cells, anchoring the virus to its preferred portal of entry. Once attached, the virion is taken up by receptor-mediated endocytosis, and the low pH of the endosome triggers a conformational change in hemagglutinin that fuses the viral envelope with the endosomal membrane. This allows uncoating of the viral ribonucleoprotein complexes and their import into the host cell nucleus, where the viral RNA-dependent RNA polymerase executes replication and transcription. Neuraminidase then cleaves terminal sialic acid residues from the host cell surface, preventing newly formed virions from aggregating and permitting efficient budding and dissemination throughout the respiratory tract.

Environmental conditions in the National Capital Region play a decisive role in shaping transmission dynamics, and they differ sharply from the patterns seen in temperate climates. Rather than producing a single crisp winter peak, northern India experiences seasonal viral persistence predisposed by high ambient humidity, monsoon precipitation, and subsequent winter thermal inversions that trap polluted air close to the ground. High humidity and poor air circulation in enclosed spaces facilitate the stability and transport of fine micro-aerosols alongside the larger respiratory droplets generated by coughing, sneezing, and even vocalization. Indoor crowding during spells of inclement weather increases close-contact exposure, while contaminated environmental surfaces serve as secondary vectors for indirect mucosal self-inoculation when people touch their faces after contact with contaminated fomites. Following exposure, the virus exhibits an incubation period of roughly one to four days, a window during which asymptomatic or presymptomatic viral shedding can seed community transmission chains well before the first overt clinical presentation, complicating efforts to contain spread through symptom-based screening alone.

The clinical spectrum of A(H1N1) infection ranges from mild, uncomplicated upper respiratory illness to fulminant, life-threatening systemic disease. Typical uncomplicated cases present with abrupt-onset fever, non-productive cough, pharyngeal erythema, nasal congestion, severe retro-orbital or generalized headache, diffuse myalgia, and profound constitutional fatigue. Pediatric cohorts frequently show prominent gastrointestinal involvement, including nausea, vomiting, and diarrhea, layered on top of systemic febrile illness. In a subset of patients, viral tropism for the lower respiratory tract precipitates rapid tissue damage, characterized by necrotizing tracheobronchitis, diffuse alveolar damage, impaired gas exchange, and eventual acute respiratory distress syndrome. Viral destruction of the respiratory epithelium also strips away a critical innate barrier, leaving the lower airways highly vulnerable to secondary bacterial superinfections, most notably those caused by Streptococcus pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes. These bacterial complications historically account for a substantial share of influenza-related morbidity and mortality, which is why clinicians are urged to watch for clinical deterioration beyond the expected viral course.

Identifying high-risk populations is central to early intervention and rational allocation of scarce clinical resources. Pregnant women represent an exceptionally vulnerable cohort because physiological alterations in cell-mediated immunity, decreased chest wall compliance, and elevated maternal oxygen consumption collectively heighten the risk of rapid pulmonary decompensation. The extreme age groups face elevated danger as well: infants under five years experience heightened morbidity because of immature immune responses, while adults aged sixty-five and older are compromised by immunosenescence, the gradual decline of immune function with age. Individuals with underlying chronic comorbidities, including diabetes mellitus, chronic obstructive pulmonary disease, bronchial asthma, congestive heart failure, chronic renal insufficiency, hepatic dysfunction, neurological disorders, morbid obesity, and active immunosuppression, face significantly higher rates of hospitalization, intensive care unit admission, and death. For these groups, clinicians emphasize that even seemingly mild respiratory symptoms early in an influenza wave warrant a low threshold for testing and antiviral treatment.

Clinical monitoring during the surge must emphasize rapid detection of red-flag indicators that signal acute physiological deterioration. In adults, key warning signs requiring immediate emergency evaluation include progressive dyspnea, tachypnea, persistent central chest pressure, low peripheral oxygen saturation, central cyanosis, acute alteration of mental status, persistent high fever unresponsive to antipyretics, or a clinical relapse following transient symptom resolution. That last pattern, a biphasic worsening after apparent improvement, is particularly concerning because it often heralds secondary bacterial pneumonia. In pediatric patients, critical warning indicators include intercostal retractions, grunting, nasal flaring, lethargy, poor oral fluid intake leading to dehydration, persistent irritability, and breakthrough febrile seizures. Prompt recognition of these signs facilitates timely admission to higher-level care facilities capable of providing advanced respiratory support, including oxygen therapy and mechanical ventilation, which can be decisive in severe lower respiratory tract disease.

Definitive clinical management, the analysis stresses, relies on rigorous diagnostic testing and targeted pharmacological therapy rather than empirical broad-spectrum interventions. Reverse transcription-polymerase chain reaction remains the gold standard diagnostic technique for hospitalized or severe cases, enabling accurate differentiation of H1N1 from co-circulating respiratory pathogens such as SARS-CoV-2, respiratory syncytial virus, adenovirus, and bacterial pneumonia. This differential matters because treatment pathways diverge sharply: antivirals benefit influenza, whereas antibacterial agents are clinically ineffective against a primary viral pathogen and contravene global antimicrobial stewardship principles when used empirically. The authors are emphatic that antibiotics should be strictly reserved for cases with confirmed or highly suspected secondary bacterial co-infections, a discipline that protects both individual patients from unnecessary drug exposure and the broader community from accelerating antimicrobial resistance, an already serious problem in South Asian healthcare settings.

On the therapeutic front, neuraminidase inhibitors, particularly oral oseltamivir, form the cornerstone of antiviral therapy for patients with severe, progressive, or complicated disease, as well as for all high-risk individuals presenting with respiratory illness during the surge. Timing is critical: antiviral treatment provides optimal benefit when initiated within 48 hours of symptom onset, significantly dampening viral replication, shortening the duration of illness, and lowering the incidence of severe complications. Meta-analytic evidence from hospitalized H1N1pdm09 cohorts has linked early neuraminidase inhibitor use with reduced mortality, reinforcing the case for prompt empirical treatment of high-risk patients even before laboratory confirmation returns. Because the drug targets the neuraminidase protein rather than the hemagglutinin antigen that drifts seasonally, it retains activity against the A/Missouri/11/2025-like variant now circulating in India, providing a reliable pharmacological backstop while vaccination programs catch up.

Prevention, ultimately, remains the most cost-effective strategy, and the authors outline a comprehensive, layered framework. Annual seasonal influenza vaccination sits at its core, with the current vaccine exhibiting strong antigenic concordance with the circulating A(H1N1)pdm09 clade, a consequence of the World Health Organization’s strain selection for the 2025-2026 Northern Hemisphere season. Around that pharmacological anchor, the framework integrates non-pharmaceutical interventions: home isolation of symptomatic individuals, frequent hand hygiene, respiratory etiquette, enhanced indoor ventilation, and the use of well-fitted N95 respirators in high-density environments such as public transport, markets, and healthcare facilities. For a densely populated tropical and subtropical megaregion where monsoon humidity and winter thermal inversions prolong viral viability, these measures collectively reduce the effective reproduction number of the virus. The 2026 surge, the analysis concludes, is a reminder that seasonal influenza remains a formidable and recurring public health threat, but one whose trajectory can be substantially blunted by surveillance, vaccination, judicious antiviral use, and disciplined antimicrobial stewardship.

Subject of Research: The 2026 seasonal resurgence of influenza A(H1N1)pdm09 in India and evidence-based strategies for its prevention and clinical management

Article Title: H1N1 seasonal surge in India, 2026: Emerging public health threat and evidence based preventive strategies

Article References: Choudhary, O. P., & Choudhary, P. (2026). H1N1 seasonal surge in India, 2026: Emerging public health threat and evidence based preventive strategies. New Microbes and New Infections, 73, Article 101836. https://doi.org/10.1016/j.nmni.2026.101836

Image Credits: AI Generated

DOI: 10.1016/j.nmni.2026.101836

Keywords: H1N1, influenza A(H1N1)pdm09, India, Delhi-NCR, seasonal influenza, oseltamivir, neuraminidase inhibitors, influenza vaccination, RT-PCR, respiratory transmission, public health surveillance, antimicrobial stewardship