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Search Results (417)

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12 pages, 278 KiB  
Article
A Series of Severe and Critical COVID-19 Cases in Hospitalized, Unvaccinated Children: Clinical Findings and Hospital Care
by Vânia Chagas da Costa, Ulisses Ramos Montarroyos, Katiuscia Araújo de Miranda Lopes and Ana Célia Oliveira dos Santos
Epidemiologia 2025, 6(3), 40; https://doi.org/10.3390/epidemiologia6030040 - 4 Aug 2025
Abstract
Background/Objective: The COVID-19 pandemic profoundly transformed social life worldwide, indiscriminately affecting individuals across all age groups. Children have not been exempted from the risk of severe illness and death caused by COVID-19. Objective: This paper sought to describe the clinical findings, laboratory and [...] Read more.
Background/Objective: The COVID-19 pandemic profoundly transformed social life worldwide, indiscriminately affecting individuals across all age groups. Children have not been exempted from the risk of severe illness and death caused by COVID-19. Objective: This paper sought to describe the clinical findings, laboratory and imaging results, and hospital care provided for severe and critical cases of COVID-19 in unvaccinated children, with or without severe asthma, hospitalized in a public referral service for COVID-19 treatment in the Brazilian state of Pernambuco. Methods: This was a case series study of severe and critical COVID-19 in hospitalized, unvaccinated children, with or without severe asthma, conducted in a public referral hospital between March 2020 and June 2021. Results: The case series included 80 children, aged from 1 month to 11 years, with the highest frequency among those under 2 years old (58.8%) and a predominance of males (65%). Respiratory diseases, including severe asthma, were present in 73.8% of the cases. Pediatric multisystem inflammatory syndrome occurred in 15% of the children, some of whom presented with cardiac involvement. Oxygen therapy was required in 65% of the cases, mechanical ventilation in 15%, and 33.7% of the children required intensive care in a pediatric intensive care unit. Pulmonary infiltrates and ground-glass opacities were common findings on chest X-rays and CT scans; inflammatory markers were elevated, and the most commonly used medications were antibiotics, bronchodilators, and corticosteroids. Conclusions: This case series has identified key characteristics of children with severe and critical COVID-19 during a period when vaccines were not yet available in Brazil for the study age group. However, the persistence of low vaccination coverage, largely due to parental vaccine hesitancy, continues to leave children vulnerable to potentially severe illness from COVID-19. These findings may inform the development of public health emergency contingency plans, as well as clinical protocols and care pathways, which can guide decision-making in pediatric care and ensure appropriate clinical management, ultimately improving the quality of care provided. Full article
11 pages, 666 KiB  
Article
Low Hepatitis B Immunity Among Ukrainian Refugee Children and Adolescents in Poland: Need for Targeted Screening and Vaccination
by Lidia Stopyra, Karolina Banach, Magdalena Wood, Justyna Stala and Anna Merklinger-Gruchała
Vaccines 2025, 13(8), 816; https://doi.org/10.3390/vaccines13080816 - 31 Jul 2025
Viewed by 262
Abstract
Background: The 2022 conflict in Ukraine triggered mass migration, leading to a significant influx of Ukrainian refugee children into Poland. This situation raises concerns about hepatitis B virus immunity, as Ukraine’s hepatitis B vaccination coverage has been inconsistent compared to Poland’s high vaccination [...] Read more.
Background: The 2022 conflict in Ukraine triggered mass migration, leading to a significant influx of Ukrainian refugee children into Poland. This situation raises concerns about hepatitis B virus immunity, as Ukraine’s hepatitis B vaccination coverage has been inconsistent compared to Poland’s high vaccination rates. Objective: To evaluate hepatitis B immunity and infection prevalence among Ukrainian refugee children residing in Southern Poland and to assess implications for vaccination strategies in the host country. Methods: A prospective cross-sectional study was conducted on 1322 Ukrainian refugee children (0–18 years) presenting to a pediatric infectious diseases department in Southern Poland between February 2022 and March 2024. Data on vaccination history, demographic characteristics, and selected laboratory parameters, including hepatitis B surface antigen and anti-HBs antibody levels, were collected. Protective immunity was defined as anti-HBs antibody levels ≥10 IU/L. Results: Among the participants (mean age 9.9 years; 50.2% female), 83.2% were reported as vaccinated according to national immunization programs, but only 64.9% demonstrated protective anti-HBs antibody levels. Protective antibody prevalence declined significantly with age, with less than half of adolescents aged 15–18 years showing immunity. Five children (0.4%) were diagnosed with chronic hepatitis B, four of whom were unvaccinated. Conclusions: This study identifies a significant gap in hepatitis B immunity among Ukrainian adolescent refugees residing in Southern Poland, with less than half possessing protective anti-HBs antibody levels. This immunity gap and the high risk of sexual transmission of the hepatitis B virus in adolescents highlight the urgent need for comprehensive surveillance, screening, and catch-up vaccination programs. Full article
(This article belongs to the Special Issue Vaccination, Public Health and Epidemiology)
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13 pages, 2893 KiB  
Article
Vaccine Attitudes, Knowledge, and Confidence Among Nursing, Pediatric Nursing, and Midwifery Undergraduate Students in Italy
by Ersilia Buonomo, Daniele Di Giovanni, Gaia Piunno, Stefania Moramarco, Giuliana D’Elpidio, Ercole Vellone, Enkeleda Gjini, Mariachiara Carestia, Cristiana Ferrari and Luca Coppeta
Vaccines 2025, 13(8), 813; https://doi.org/10.3390/vaccines13080813 - 30 Jul 2025
Viewed by 182
Abstract
Background: Vaccine hesitancy (VH) represents a growing concern among healthcare professionals and students, potentially undermining public health efforts. Nursing, pediatric nursing, and midwifery students are future vaccinators and educators, making it essential to understand their attitudes, knowledge, and confidence toward vaccination. This study [...] Read more.
Background: Vaccine hesitancy (VH) represents a growing concern among healthcare professionals and students, potentially undermining public health efforts. Nursing, pediatric nursing, and midwifery students are future vaccinators and educators, making it essential to understand their attitudes, knowledge, and confidence toward vaccination. This study aims to assess vaccine-related perceptions and behaviors among these student populations in an Italian university. Methods: A cross-sectional survey was conducted between November 2022 and February 2024 at the University of Rome “Tor Vergata”. A structured, anonymous questionnaire, including the Vaccination Attitudes Examination (VAX) scale, vaccine knowledge items, and sources of information, was administered to students in nursing (n = 205), pediatric nursing (n = 46), and midwifery (n = 21). Statistical analyses included descriptive statistics, ANOVA, post hoc tests, and Mann–Whitney U tests. Results: Among the 272 participants, 20.6% reported refusing at least one recommended vaccine, and 18.4% delayed vaccination for non-medical reasons. Vaccine knowledge and confidence increased significantly with academic progression (p < 0.001). Midwifery students showed both the highest concern for long-term vaccine effects and the greatest confidence in vaccine safety. Institutional and scientific sources were the most trusted, though traditional and non-institutional media also influenced perceptions, particularly among midwifery students. Conclusions: Despite high COVID-19 vaccine uptake, VH persists among health professional students. Discipline-specific patterns highlight the need for early, targeted educational strategies to enhance vaccine literacy and reduce hesitancy. Tailored training may empower future professionals to become informed and credible advocates for vaccination. Full article
(This article belongs to the Special Issue Acceptance and Hesitancy in Vaccine Uptake: 2nd Edition)
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12 pages, 691 KiB  
Article
A Novel Approach to Estimate the Impact of PCV20 Immunization in Children by Incorporating Indirect Effects to Generate the Number Needed to Vaccinate
by Mark H. Rozenbaum, Maria J. Tort, Blair Capitano, Ruth Chapman, Desmond Dillon-Murphy, Benjamin M. Althouse and Alejandro Cane
Vaccines 2025, 13(8), 805; https://doi.org/10.3390/vaccines13080805 - 29 Jul 2025
Viewed by 264
Abstract
Background/Objectives: The number needed to vaccinate (NNV) is a metric commonly used to evaluate the public health impact of a vaccine as it represents the number of individuals that must be vaccinated to prevent one case of disease. Traditional calculations may underestimate vaccine [...] Read more.
Background/Objectives: The number needed to vaccinate (NNV) is a metric commonly used to evaluate the public health impact of a vaccine as it represents the number of individuals that must be vaccinated to prevent one case of disease. Traditional calculations may underestimate vaccine benefits by neglecting indirect effects and duration of protection (DOP), resulting in NNV overestimation. This study evaluated the NNV for the pediatric 20-valent pneumococcal conjugate (PCV20) US immunization program, as compared to PCV13, with a unique approach to NNV. Methods: A multi-cohort, population-based Markov model accounting for indirect effects was employed to calculate the NNV of PCV20 to avert a case of pneumococcal disease, invasive pneumococcal disease (IPD), hospitalized non-bacteremic pneumonia (NBP), ambulatory NBP, and otitis media (OM), as well as to prevent antibiotic-resistant cases and antibiotic prescriptions. Results: The mean NNV over a 25-year time horizon to prevent one case of pneumococcal disease was 6, with NNVs of 854 for IPD, 106 for hospitalized NBP, 25 for outpatient NBP, and 9 for OM, 11 for a course of antibiotic, and 4 for resistant disease. The mean NNV per year decreased over time, reflecting the DOP and increasing indirect effects over time. Conclusions: This study presents a novel approach to NNVs and shows that relatively few vaccinations are required to prevent disease. The decrease in NNV over time highlights the necessity of including DOP and indirect effects in NNV calculations, ensuring a more realistic assessment of a vaccine’s impact. Full article
(This article belongs to the Special Issue Estimating Vaccines' Value and Impact)
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15 pages, 271 KiB  
Review
The Number Needed to Immunize (NNI) to Assess the Benefit of a Prophylaxis Intervention with Monoclonal Antibodies Against RSV
by Sara Boccalini, Veronica Gironi, Primo Buscemi, Paolo Bonanni, Barbara Muzii, Salvatore Parisi, Marta Borchiellini and Angela Bechini
Vaccines 2025, 13(8), 791; https://doi.org/10.3390/vaccines13080791 - 25 Jul 2025
Viewed by 365
Abstract
Introduction: Respiratory Syncytial Virus (RSV) is the leading cause of lower respiratory tract infections in infants and children, as well as hospitalizations for respiratory infections in the pediatric population, representing a significant public health concern. Nirsevimab, a long-acting anti-RSV monoclonal antibody, has recently [...] Read more.
Introduction: Respiratory Syncytial Virus (RSV) is the leading cause of lower respiratory tract infections in infants and children, as well as hospitalizations for respiratory infections in the pediatric population, representing a significant public health concern. Nirsevimab, a long-acting anti-RSV monoclonal antibody, has recently been approved by the European Medicines Agency (EMA). The aim of this study is to assess the utility of certain parameters, such as the Number Needed to Immunize (NNI), in supporting decision-makers regarding the introduction of nirsevimab as a universal prophylactic measure. Methods: A literature review was conducted to identify the definition and application of the NNI in the context of infectious disease prevention. The following online databases were consulted: Scopus, MEDLINE, Google Scholar, Web of Science, and Cochrane Library. The search was restricted to English-language texts published between 1 January 2000 and 30 January 2025. Results: The NNI represents the number of individuals who need to be immunized to prevent clinical outcomes such as medical visits and hospitalizations caused by infectious diseases. Six studies were identified that utilized this parameter to outline the benefits of immunization and describe the advantages of using monoclonal antibodies for RSV disease. Finelli and colleagues report that to prevent one RSV-related hospitalization, 37–85 infants aged 0–5 months and 107–280 infants aged 6–11 months would need to be immunized with long-acting anti-RSV antibodies. A recent study by Mallah et al. on the efficacy of nirsevimab estimates that the NNI required to prevent one RSV-related hospitalization is 25 infants. Studies by Francisco and O’Leary report NNI values of 82 and 128 infants, respectively, to prevent one RSV-related hospitalization with nirsevimab. Mallah et al. describe NNI as a metric useful to quantify the immunization effort needed to prevent a single RSV hospitalization. A recent Italian study reports that 35 infants need to be immunized to prevent one hospitalization due to RSV-LRTI and 3 infants need to be immunized to prevent one primary care visit due to RSV-LRTI. The studies indicate that the NNI for anti-RSV monoclonal antibodies is lower than the corresponding Number Needed to Vaccinate (NNV) for vaccines already included in national immunization programs. The main limitations of using this parameter include the absence of a shared threshold for interpreting results and the lack of consideration for the indirect effects of immunization on the population. Conclusions: The NNI is an easily understandable tool that can be used to convey the value of an immunization intervention to a variety of stakeholders, thereby supporting public health decision-making processes when considered in association with the uptake of the preventative strategy. At the current status, the estimated NNI of monoclonal antibodies against RSV results favourable and confirms the use in the first year of life for the prevention of RSV disease. Full article
11 pages, 1036 KiB  
Article
The Re-Emergence of Pediatric Pertussis: Insights from a Regional Romanian Hospital
by Ioana Rosca, Alina Turenschi, Alexandru Dinulescu and Victoria Lichii
Antibiotics 2025, 14(7), 730; https://doi.org/10.3390/antibiotics14070730 - 21 Jul 2025
Viewed by 362
Abstract
Introduction: Pertussis, a vaccine-preventable disease caused by Bordetella pertussis, is resurging globally due to declining immunization rates. This study explores the clinical and epidemiological features of pediatric pertussis cases in a regional Romanian hospital amid growing vaccine hesitancy. Methods: We conducted a retrospective [...] Read more.
Introduction: Pertussis, a vaccine-preventable disease caused by Bordetella pertussis, is resurging globally due to declining immunization rates. This study explores the clinical and epidemiological features of pediatric pertussis cases in a regional Romanian hospital amid growing vaccine hesitancy. Methods: We conducted a retrospective cohort study on 99 children diagnosed with pertussis and admitted to Ploiești Pediatric Hospital between January 2024 and January 2025. Demographic, clinical, laboratory, and radiological data were analyzed using SPSS 25.0. Results: The median age was 11 months (IQR 4–25), with 12.1% under two months, and ineligible for the first DTaP dose. Notably, 72.7% of children were unvaccinated; 59.4% had missed scheduled doses. None of the mothers received the DTaP vaccination during pregnancy. Most cases (55.6%) had bilaterally accentuated interstitial patterns on chest X-ray, significantly associated with vaccination status (p = 0.019). The leukocyte count was higher in children with alveolar infiltrates (p = 0.028), and as the number of vaccine doses increased, the leukocyte count tended to slightly decrease (p = 0.022, R = −0.229). PCR confirmation was obtained after a mean of 2.2 days, with 12.1% of cases confirmed post-discharge. Azithromycin was used in 74.7% of cases, with good tolerability. Conclusions: Low pediatric and maternal vaccine uptake was a major contributor to pertussis resurgence in this cohort. Radiological severity correlated with vaccination status, suggesting that vaccination may confer protection not only against infection but also against severe pulmonary involvement. These findings support urgent public health efforts to restore vaccine confidence and coverage, particularly among vulnerable infant populations and expectant mothers. Full article
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25 pages, 5421 KiB  
Article
NOD2 (Nucleotide-Binding Oligomerization Domain-Containing Protein 2)-Mediated Modulation of the Immune Response Induced by BCG (Bacillus Calmette-Guérin) Bacilli
by Magdalena Jurczak, Joanna Kaczmarek, Magdalena Kowalewska-Pietrzak, Paulina Stelmach and Magdalena Druszczynska
Pathogens 2025, 14(7), 683; https://doi.org/10.3390/pathogens14070683 - 11 Jul 2025
Viewed by 405
Abstract
The Bacillus Calmette-Guérin (BCG) vaccine confers broad, non-specific immunity that may bolster defenses against respiratory viruses. While NOD2 (nucleotide-binding oligomerization domain-containing protein 2)-driven pathways are central to innate immune responses, the contribution of surface receptor modulation on monocytes to shaping these responses remains [...] Read more.
The Bacillus Calmette-Guérin (BCG) vaccine confers broad, non-specific immunity that may bolster defenses against respiratory viruses. While NOD2 (nucleotide-binding oligomerization domain-containing protein 2)-driven pathways are central to innate immune responses, the contribution of surface receptor modulation on monocytes to shaping these responses remains underexplored. We analyzed whole-blood cultures from BCG-vaccinated Polish children, stratified by serostatus to SARS-CoV-2 and RSV, and stimulated for 48 h with live BCG, purified viral antigens, or both. RT-qPCR quantified mRNA levels of NOD2 and key cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, TNF), while flow cytometry assessed CD14, HLA-DR, CD11b, and CD206 expression. Co-stimulation with BCG + RSV elicited the strongest transcriptional response, notably a 2–4-fold upregulation of NOD2, IL-1β, and IL-6 versus RSV alone. In SARS-CoV-2(+) donors, RSV alone induced higher NOD2 expression than BCG or BCG + RSV, while IL-2 peaked following BCG + SARS-CoV-2. Across conditions, NOD2 positively correlated with IL-4 and IL-6 but negatively correlated with IL-1β in SARS-CoV-2 cultures. Viral antigens increased CD14 and HLA-DR on monocytes, suggesting activation; CD206 rose only in dual-seropositive children. Our findings indicate that BCG stimulation affects pediatric antiviral immunity through NOD2-related cytokine production and induction of a CD14+HLA-DR+ phenotype, supporting its potential role in boosting innate defenses against respiratory pathogens. Full article
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12 pages, 631 KiB  
Review
Challenges and Limitations of Current RSV Prevention Strategies in Infants and Young Children: A Narrative Review
by Nicola Principi, Serafina Perrone and Susanna Esposito
Vaccines 2025, 13(7), 717; https://doi.org/10.3390/vaccines13070717 - 1 Jul 2025
Cited by 1 | Viewed by 750
Abstract
Background: Respiratory syncytial virus (RSV) remains a leading cause of lower respiratory tract infections and hospitalizations in infants and young children globally. Recently, RSV prevention has advanced with the introduction of nirsevimab, a long-acting monoclonal antibody, and the RSV preF vaccine for maternal [...] Read more.
Background: Respiratory syncytial virus (RSV) remains a leading cause of lower respiratory tract infections and hospitalizations in infants and young children globally. Recently, RSV prevention has advanced with the introduction of nirsevimab, a long-acting monoclonal antibody, and the RSV preF vaccine for maternal immunization. While these interventions have improved early protection, several limitations hinder their broader impact and long-term effectiveness. Methods: This narrative review synthesizes evidence from clinical trials, observational studies, and regulatory reports to evaluate the main limitations of nirsevimab and maternal RSV vaccination. Literature searches were conducted in major databases, focusing on efficacy, safety, immunogenicity, implementation, and population-specific challenges. Results: Both nirsevimab and maternal vaccination provide strong protection during the first six months of life, but their effectiveness wanes thereafter. This is concerning as nearly half of RSV-related deaths occur in children over six months old. Maternal vaccine efficacy is uncertain in very-preterm infants, and safety concerns persist, including potential associations with preterm birth, Guillain–Barré syndrome, and hypertensive disorders. Real-world data from low-income countries are lacking, limiting generalizability. Additionally, the risk of vaccine-associated enhanced disease (VAED), although unconfirmed, has delayed pediatric vaccine development. Emerging monoclonal antibodies and live-attenuated vaccines are under investigation to extend protection beyond infancy. Conclusions: Despite substantial progress, current RSV prevention strategies leave critical gaps, particularly for older infants and underserved populations. There is a pressing need for next-generation vaccines, enhanced pharmacovigilance, and equitable global implementation to ensure sustained and inclusive RSV protection. Full article
(This article belongs to the Special Issue Respiratory Syncytial Virus (RSV) Vaccine)
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13 pages, 461 KiB  
Article
How Immunization Information Systems Inform Age-Based HPV Vaccination Recommendations in the United States: A Mixed-Methods Study
by Nadja A. Vielot, Isabelle K. Bucklin, Kristy Westfall, Deanna Kepka, Gregory Zimet and Sherri Zorn
Vaccines 2025, 13(7), 716; https://doi.org/10.3390/vaccines13070716 - 30 Jun 2025
Viewed by 480
Abstract
Background: Immunization information systems (IISs) in the United States forecast vaccine due dates, which can inform when providers recommend vaccines to patients. IIS forecasting for HPV vaccination at 9 years, the minimum age of licensure, and when vaccination is likely most effective [...] Read more.
Background: Immunization information systems (IISs) in the United States forecast vaccine due dates, which can inform when providers recommend vaccines to patients. IIS forecasting for HPV vaccination at 9 years, the minimum age of licensure, and when vaccination is likely most effective is not documented or well-understood. Methods: We documented characteristics of HPV vaccination forecasts in jurisdictional IISs through Internet searches and requests to immunization program managers. Next, we conducted focus groups with stakeholders from seven jurisdictions to elucidate their processes for determining and implementing HPV vaccination forecasts. Results: Forecast data were available from 49 out of 64 CDC-funded jurisdictions, of which 14 (29%) recommended HPV vaccination at age 9 and 35 (71%) recommended HPV vaccination starting at ages 11 through to 15. Jurisdictions that recommended HPV vaccination at age 9 cited the positions of the American Cancer Society and American Academy of Pediatrics and reported little or no provider opposition to this recommendation. Jurisdictions reported variable flexibility in programming their forecasts. Those that changed their HPV vaccination forecast from 11 to 9 years did so easily while some experienced limitations. Other jurisdictions adhered strictly to the CDC’s routine recommendation at age 11–12 years and would only update the forecast in tandem with updated CDC guidance. The impact of IISs and electronic health record interoperability on how providers view and utilize IIS forecasting is unclear. Conclusions: Jurisdictions can share best practices for forecasting at 9 and future studies can evaluate the effects of forecasting age on the vaccination rates, providing evidence for nationwide vaccination recommendations. Full article
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13 pages, 277 KiB  
Case Report
Beyond Passive Immunity: Three Neonatal Influenza Cases Highlighting Impact of Missed Maternal Vaccination
by Irina Profir, Cristina-Mihaela Popescu, Gabriel Valeriu Popa and Aurel Nechita
Clin. Pract. 2025, 15(7), 124; https://doi.org/10.3390/clinpract15070124 - 30 Jun 2025
Viewed by 390
Abstract
Background: Neonatal influenza is a rare condition. Young infants have immature immune defenses and are unable to receive direct vaccination; this can result in significant illness. Maternal anti-influenza immunization during pregnancy provides passive antibodies to the newborn via transplacental transfer, significantly decreasing [...] Read more.
Background: Neonatal influenza is a rare condition. Young infants have immature immune defenses and are unable to receive direct vaccination; this can result in significant illness. Maternal anti-influenza immunization during pregnancy provides passive antibodies to the newborn via transplacental transfer, significantly decreasing the incidence and severity of influenza in early infancy. Nevertheless, the vaccination coverage during pregnancy remains low in many regions, leaving certain neonates without adequate protection. Methods: We present three cases of laboratory-confirmed influenza infection in neonates admitted to the “Sf. Ioan” Clinical Emergency Pediatric Hospital in Galați and conduct a literature review. The clinical presentation, co-infections, timing of antiviral therapy, laboratory findings, maternal vaccination status, and outcomes (including the hospitalization duration and recovery) were systematically analyzed for each case. Results: All three neonates were full-term and previously healthy, born to mothers who had not received influenza vaccinations during their pregnancies. They presented at ages ranging from 2 to 4 weeks with fever, respiratory symptoms including a cough, nasal congestion, and respiratory distress, as well as feeding difficulties. One case involved a co-infection with Bordetella pertussis, which manifested as a severe paroxysmal cough, cyanosis, and apnea. Laboratory findings in the cases with influenza alone indicated leukopenia accompanied by normal C-reactive protein levels. In the co-infection case, leukocytosis, lymphocytosis, and thrombocytosis were observed. All the infants received oseltamivir treatment within 48 h of the symptom onset; the case with pertussis co-infection also received azithromycin. Each infant required supplemental oxygen, but none necessitated mechanical ventilation. Clinical improvement was observed in all cases, with hospitalization ranging from 6 to 7 days and complete recovery without complications. Conclusions: Neonatal influenza may result in considerable morbidity, particularly in infants born to unvaccinated mothers. Positive outcomes, however, have been correlated with early diagnosis and antiviral treatment. Pertussis co-infection may exacerbate clinical progression, underscoring the importance of maternal immunization against both influenza and pertussis. In this case series, we aim to present three cases of laboratory-confirmed influenza in neonates born to mothers who were not immunized against influenza during pregnancy. These cases highlight the clinical presentations of neonatal influenza, underscore the risks associated with pertussis co-infection, and reinforce the importance of maternal influenza and Tdap vaccination for preventing severe outcomes in newborns. Full article
32 pages, 1959 KiB  
Review
hMPV Outbreaks: Worldwide Implications of a Re-Emerging Respiratory Pathogen
by Alexandra Lianou, Andreas G. Tsantes, Petros Ioannou, Efstathia-Danai Bikouli, Anastasia Batsiou, Aggeliki Kokkinou, Kostantina A. Tsante, Dionysios Tsilidis, Maria Lampridou, Nicoletta Iacovidou and Rozeta Sokou
Microorganisms 2025, 13(7), 1508; https://doi.org/10.3390/microorganisms13071508 - 27 Jun 2025
Viewed by 846
Abstract
Human metapneumovirus (hMPV), a member of the Pneumoviridae subfamily, has emerged as a significant etiological agent of acute respiratory tract infections across diverse age groups, particularly affecting infants, the elderly, and immunocompromised individuals. Since its initial identification in 2001, hMPV has been recognized [...] Read more.
Human metapneumovirus (hMPV), a member of the Pneumoviridae subfamily, has emerged as a significant etiological agent of acute respiratory tract infections across diverse age groups, particularly affecting infants, the elderly, and immunocompromised individuals. Since its initial identification in 2001, hMPV has been recognized globally for its seasonal circulation pattern, predominantly in late winter and spring. hMPV is a leading etiological agent, accounting for approximately 5% to 10% of hospitalizations among pediatric patients with acute respiratory tract infections. hMPV infection can result in severe bronchiolitis and pneumonia, particularly in young children, with clinical manifestations often indistinguishable from those caused by human RSV. Primary hMPV infection typically occurs during early childhood; however, re-infections are frequent and may occur throughout an individual’s lifetime. hMPV is an enveloped, negative-sense RNA virus transmitted through respiratory droplets and aerosols, with a 3–5-day incubation period. The host immune response is marked by elevated pro-inflammatory cytokines, which contribute to disease severity. Advances in molecular diagnostics, particularly reverse transcription–quantitative polymerase chain reaction (RT-qPCR) and metagenomic next-generation sequencing (mNGS), have improved detection accuracy and efficiency. Despite these advancements, treatment remains largely supportive, as no specific antiviral therapy has yet been approved. Promising developments in vaccine research, including mRNA-based candidates, are currently undergoing clinical evaluation. This review synthesizes current knowledge on hMPV, highlighting its virological, epidemiological, and clinical characteristics, along with diagnostic advancements and emerging therapeutic strategies, while underscoring the critical role of continued research and sustained preventive measures—including vaccines, monoclonal antibodies, and non-pharmaceutical interventions—in mitigating the global burden of hMPV-related disease. Full article
(This article belongs to the Special Issue Emerging and Re-Emerging Infections in the Immunocompromised Host)
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16 pages, 959 KiB  
Article
Impact of Prior SARS-CoV-2 Infection on COVID-19 Vaccine Effectiveness in Children and Adolescents in Norway and Italy
by Elisa Barbieri, Nhung T. H. Trinh, Costanza Di Chiara, Giovanni Corrao, Riccardo Boracchini, Ester Rosa, Cecilia Liberati, Daniele Donà, Angela Lupattelli, Carlo Giaquinto and Anna Cantarutti
Vaccines 2025, 13(7), 698; https://doi.org/10.3390/vaccines13070698 - 27 Jun 2025
Viewed by 459
Abstract
Background and objective: The approval of mRNA-based vaccines for children and adolescents has contributed to global efforts to control the SARS-CoV-2 pandemic. While hybrid immunity—combining prior SARS-CoV-2 infection and vaccination—may offer enhanced protection, data on its effectiveness versus vaccine-induced immunity in the [...] Read more.
Background and objective: The approval of mRNA-based vaccines for children and adolescents has contributed to global efforts to control the SARS-CoV-2 pandemic. While hybrid immunity—combining prior SARS-CoV-2 infection and vaccination—may offer enhanced protection, data on its effectiveness versus vaccine-induced immunity in the pediatric population are limited. Methods: This retrospective matched cohort study used linked health data from Norwegian nationwide health registries and the Italian Pedianet network. The study included children and adolescents aged 5–14 years eligible for COVID-19 vaccination at the time of approval (May/September 2021 and November 2021/January 2022, respectively). Mono- and two-dose vaccination schedules were assessed, and hybrid immunity was defined as prior SARS-CoV-2 infection followed by vaccination within 12 months. Conditional Cox regression models were used to estimate hazard ratios (HRs) for SARS-CoV-2 infection risk, adjusting for sociodemographics, comorbidities, and healthcare utilization. Results: The study included 626,537 children and adolescents in Norway and 38,938 in Italy. A single dose of the vaccine did not reduce the risk of infection among SARS-CoV-2–naive individuals in Norway (HR: 1.05; 95% CI: 1.04–1.07), whereas it was associated with an 8% risk reduction in Italy (HR: 0.92; 95% CI: 0.88–0.96). Among individuals with a recent prior infection (within 12 months), vaccination was associated with a reduced risk of reinfection in Norway (HR: 0.10; 95% CI: 0.05–0.13), but not in Italy (HR: 1.22; 95% CI: 0.83–1.80), compared to no vaccination. Among those with prior infection, vaccination was associated with a significantly reduced risk of reinfection in Norway (HR = 0.10; 95% CI: 0.05–0.20), but not in Italy (HR = 0.55; 95% CI: 0.27–1.11). Hybrid immunity provided greater protection against (re-)infection compared to vaccine-induced immunity alone, with a 26% risk reduction observed in Norway (HR = 0.74; 95% CI = 0.47–0.1.16) and an 86% reduction in Italy (HR = 0.14; 95% CI = 0.09–0.21). Conclusions: This analysis supports the effectiveness of SARS-CoV-2 vaccines in children, with hybrid immunity offering enhanced protection against reinfection. Given the waning effectiveness of vaccines over time, continued research and booster strategies are essential to sustain protection and mitigate transmission. Full article
(This article belongs to the Special Issue Advance Public Health Through Vaccination)
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19 pages, 1819 KiB  
Article
Rotavirus alphagastroenteritidis: Circulating Strains After the Introduction of the Rotavirus Vaccine (Rotarix®) in Luanda Province of Angola
by Dikudila G. Vita, Cristina Santiso-Bellón, Manuel Lemos, Zoraima Neto, Elsa Fortes-Gabriel, Miguel Brito, Cruz S. Sebastião, Jesus Rodriguez-Diaz, Celso Cunha and Claudia Istrate
Viruses 2025, 17(6), 858; https://doi.org/10.3390/v17060858 - 17 Jun 2025
Viewed by 850
Abstract
Rotavirus alphagastroenteritidis (R. alphagastroenteritidis) remains the leading cause of pediatric diarrhea. Although Angola introduced Rotarix®, the human monovalent R. alphagastroenteritidis vaccine since 2014 as part of its routine childhood immunization program, no follow-up study has been conducted. [...] Read more.
Rotavirus alphagastroenteritidis (R. alphagastroenteritidis) remains the leading cause of pediatric diarrhea. Although Angola introduced Rotarix®, the human monovalent R. alphagastroenteritidis vaccine since 2014 as part of its routine childhood immunization program, no follow-up study has been conducted. The aim of this study was to evaluate the distribution of R. alphagastroenteritidis genotypes among children under five years of age, hospitalized with acute gastroenteritis (AGE), after the introduction of the rotavirus vaccine. To achieve this goal, stool samples collected between 2021 and 2022 from children under 5 years of age diagnosed with AGE at six hospitals in Luanda Province were analyzed. The R. alphagastroenteritidis-antigen immunochromatographic test (SD Bioline™, Abbott, Chicago, IL, USA) was performed, and 121 positive samples were genotyped. Ten samples were randomly selected for further Sanger sequencing. The results showed that the G9P[6] was the most prevalent genotype (17.3%), followed by G9P[8] (16.5%), G2P[4] (14.9%), G3P[6] (13.2%), G8P[6] (11.5%), and less frequently G12P[8] (9.1%), G1P[6] (4.1%), and G1P[8] (2.5%). The genotype combinations G3P[6], G8P[6], and G12P[8] were detected for the first time in Luanda Province. In conclusion, the emergence of new genotype combinations supports the need for continuous surveillance to identify the trend in R. alphagastroenteritidis infection and the emergence of new strains circulating in Luanda Province in the post-vaccination period. Full article
(This article belongs to the Special Issue Viruses Associated with Gastroenteritis)
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13 pages, 499 KiB  
Article
Public Health Impact of Potential Infant MenACWY Vaccination Strategies in Spain
by Katharina Schley, Jamie Findlow, Carlos Molina, Shannon M. Sullivan and Eszter Tichy
Vaccines 2025, 13(6), 642; https://doi.org/10.3390/vaccines13060642 - 13 Jun 2025
Viewed by 643
Abstract
Background: The Spanish Interterritorial Council of the National Health System (a central government body) currently recommends vaccination against meningococcal serogroup C (MenC) at 4 and 12 months of age for prevention of invasive meningococcal disease (IMD). The Advisory Committee on Vaccines of the [...] Read more.
Background: The Spanish Interterritorial Council of the National Health System (a central government body) currently recommends vaccination against meningococcal serogroup C (MenC) at 4 and 12 months of age for prevention of invasive meningococcal disease (IMD). The Advisory Committee on Vaccines of the Spanish Association of Pediatrics (a professional medical association) and numerous Spanish regional bodies instead recommend quadrivalent vaccination against serogroups A, C, W, and Y (MenACWY) at 4 and 12 months of age. The central government and Spanish Association of Pediatrics also recommend MenACWY vaccination at 12 years of age. This study assessed the potential public health effects of replacing the MenC vaccination schedule with different MenACWY vaccination schedules in infants. Methods: Here, a static multi-cohort population model was used to evaluate potential effects on public health of IMD due to meningococcal serogroups C/W/Y, comparing MenC infant vaccination (reference strategy) against four different strategies including quadrivalent tetanus toxoid conjugate vaccine (MenACWY-TT; Nimenrix®, Pfizer Europe MA EEIG, Brussels, Belgium) infant vaccination; all strategies included MenACWY-TT vaccination at 12 years of age. Results: The most effective strategy for infant vaccination was MenACWY-TT at 2, 4, and 12 months, preventing an estimated additional 103 IMD cases, 17 deaths, and 41 cases with long-term sequelae (LTS) versus the reference strategy in the base-case IMD incidence scenario. When strategies included a two-dose infant schedule, the earlier the infant MenACWY-TT vaccine was administered, the more additional cases, deaths, and cases with LTS were prevented (base-case and high-incidence scenarios). Conclusions: This analysis supports implementation of MenACWY-TT as a replacement for MenC vaccination. Full article
(This article belongs to the Section Vaccines and Public Health)
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14 pages, 1461 KiB  
Case Report
Fatal Influenza B–MRSA Coinfection in a Healthy Adolescent: Necrotizing Pneumonia, Cytokine Storm, and Multi-Organ Failure
by Irina Profir, Cristina-Mihaela Popescu and Aurel Nechita
Children 2025, 12(6), 766; https://doi.org/10.3390/children12060766 - 13 Jun 2025
Viewed by 951
Abstract
Background: Influenza B usually causes mild illness in children. Severe and fatal cases can occur when complicated by secondary Staphylococcus aureus (S. aureus) pneumonia, including community-acquired methicillin-resistant Staphylococcus aureus (MRSA). We present a rare, rapidly progressive fatal case in an adolescent with [...] Read more.
Background: Influenza B usually causes mild illness in children. Severe and fatal cases can occur when complicated by secondary Staphylococcus aureus (S. aureus) pneumonia, including community-acquired methicillin-resistant Staphylococcus aureus (MRSA). We present a rare, rapidly progressive fatal case in an adolescent with no known medical history to highlight diagnostic and therapeutic pitfalls. Case Presentation: A 16-year-old boy with no known underlying conditions (unvaccinated for influenza) presented critically ill at “Sf. Ioan” Clinical Emergency Pediatric Hospital in Galați after one week of high fever and cough. He was in respiratory failure with septic shock, requiring immediate intubation and vasopressors. Chest X-ray (CXR) showed diffuse bilateral infiltrates (acute respiratory distress syndrome, ARDS). Initial laboratory tests revealed leukopenia, severe thrombocytopenia, disseminated intravascular coagulation (DIC), rhabdomyolysis, and acute kidney injury (AKI). Reverse transcription polymerase chain reaction (RT-PCR) confirmed influenza B, and blood cultures grew MRSA. Despite maximal intensive care, including mechanical ventilation, antibiotics (escalated for MRSA), antiviral therapy, and cytokine hemoadsorption therapy, the patient developed refractory multi-organ failure and died on hospital day 6. Autopsy revealed bilateral necrotizing pneumonia (NP) without radiographic cavitation, underscoring the diagnostic challenge. Discussion: The initial chest radiography showed diffuse bilateral pulmonary infiltrates, predominantly in the lower zones, with an ill-defined, patchy, and confluent appearance. Such appearance, in our case, was more suggestive of rapid progressive NP caused by MRSA rather than the typical pneumococcal one. This is one of the few reported cases of influenza B–MRSA coinfection with fulminant rhabdomyolysis and autopsy-confirmed necrosis. Our fulminant case illustrates the synergistic virulence of influenza and MRSA. Toxin-producing MRSA strains can cause NP and a “cytokine storm,” causing capillary leak, ARDS, shock, and DIC. Once multi-organ failure ensues, the prognosis is grim despite aggressive care. The absence of early radiographic necrosis and delayed anti-MRSA therapy (initiated after culture results) likely contributed to the poor outcome. Conclusions: Influenza B–MRSA co-infection, though rare, demands urgent empiric anti-MRSA therapy in severe influenza cases with leukopenia or shock, even without radiographic necrosis. This fatal outcome underscores the dual imperative of influenza vaccination and early, aggressive dual-pathogen targeting in high-risk presentations. Full article
(This article belongs to the Section Pediatric Infectious Diseases)
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