Background Influenza-associated neurological complications (IANC) encompass a broad spectrum ranging from febrile seizures to severe encephalopathy with substantial morbidity and mortality. We aimed to describe the clinical characteristics and outcomes of pediatric IANC and evaluate the prognostic utility of the Neuroinfluenza Severity Score (NISS). Methods This retrospective multicenter study included children aged 1 month to 18 years hospitalized with laboratory-confirmed influenza and neurological manifestations at 21 tertiary centers in Türkiye during the 2023–2025 influenza seasons. Clinical, laboratory, neuroimaging, treatment, and six-month follow-up data were analyzed. NISS was developed using variables reflecting disease severity, and outcome analysis was performed. Results Among 5,093 hospitalized children with influenza, 397 (7.8%) developed neurological complications. The median age was 45.6 months, and 70.8% were younger than five years. Seizures were the most frequent manifestation (70.8%), followed by encephalopathy (10.9%) and meningoencephalitis (5.0%). Complete neurological recovery occurred in 90.2% of patients, whereas 5.0% developed long-term neurological sequelae, and overall mortality was 1.3%. ROC analysis demonstrated excellent predictive performance of NISS for unfavorable neurological outcomes, with an optimal cutoff ≥ 2 yielding 82.1% sensitivity and 91.9% specificity (AUC 0.913, 95% CI 0.856–0.969; p < 0.001). Patients with severe neuroinfluenza were associated with delayed oseltamivir initiation, prolonged hospitalization, elevated inflammatory markers, and more frequent high-risk neuroimaging abnormalities and had significantly long-term neurological sequelae (29.5% vs. 0.6%), and mortality (8.2% vs. 0%). Conclusions IANC should be considered in children presenting with acute neurological manifestations, even in the absence of respiratory symptoms. The NISS demonstrated excellent ability to identify patients at increased risk of poor neurological outcomes, long-term sequelae, and mortality, providing a practical tool for early risk stratification and timely escalation of care.

Background/Objectives: COVID-19 vaccines may be given without requiring a negative test or absence of symptoms; however, this recommendation needs further safety evaluation. This study aimed to compare the adverse events following immunization (AEFI) between PCR-positive (asymptomatic/mildly symptomatic) and PCR-negative individuals at the time of vaccination, with a secondary objective of comparing the two vaccines (TURKOVAC and CoronaVac). Methods: This descriptive study was a secondary analysis of phase III clinical trials. Individuals who were positive for SARS-CoV-2 PCR at the time of vaccination constituted the PCR(+) group and those who tested negative or became positive after the 4th day following vaccination constituted the PCR(−) group. Whether participants had a history of COVID-19 was not considered. Results: Data from 5207 individuals were analyzed. AEFIs were more frequent in the PCR(+) group than PCR(−) group: site pain (24.5% vs. 16.7%, p < 0.001), arm pain (9.5% vs. 7.8%, p = 0.008), headache (14.8% vs. 10.0%, p < 0.001), fatigue (14.5% vs. 8.9%, p < 0.001), myalgia (12.3% vs. 7.5%, p < 0.001), sore throat (11.9% vs. 8.1%, p < 0.001), cough (7.9%; 11.1% vs. 6.9%, p < 0.001). These AEFIs were more frequent in the PCR(+) group with both vaccine groups separately. The distribution of AEFIs over time followed similar patterns in PCR(+) and PCR(−) individuals. Local AEFIs were slightly more common with the TURKOVAC, systemic AEFIs with the CoronaVac. Conclusions: While AEFIs were more common among PCR(+) group, they were mild, tolerable, and easily manageable. Our results support the suggestion that routine PCR testing prior to vaccination may not be warranted solely to mitigate concerns about anticipated adverse events.

Measles remains a significant public health concern due to its high transmissibility and potential for severe complications. Infection occurring in early childhood is associated with increased morbidity and mortality, resulting from both early and late complications. This guideline, developed by the Turkish Society of Pediatric Infectious Diseases and Immunization, presents evidence-based recommendations informed by current scientific data and national practices on the identification of measles exposures, assessment of immune status, implementation of post-exposure prophylaxis, and follow-up of exposed individuals. Post-exposure interventions play a critical role in interrupting transmission and facilitating the early identification of secondary cases. The recommendations outlined in this document emphasize the coordinated implementation of case management, contact tracing, and prophylactic measures across clinical and public health settings. By integrating national and international evidence, this guideline aims to support healthcare professionals and public health authorities with a standardized, up-to-date, and actionable framework for the prevention and control of measles.

Bugune kadar ulkemizde rutin olarak ilkogretim birinci sinifta, okullarda yapilan difteri-tetanos-aseluler bogmaca ve inaktif polio (DaBT-IPA) hatirlatma asi dozu ile kizamik-kizamikcik-kabakulak hatirlatma asi dozu, aile hekimliginde ve 48 ayda uygulanacak Cok kisa bir cevap ile, bagisiklama hizmetleri;rutin asi takvimimizin uygulanmasi, gebe asilamasi, yetiskin asilamasi-risk grubu asilamasi, koruyucu hizmetlerin temelidir ve salgin doneminde de aksatilmadan devam etmesi saglanmalidir Yazisma Adresi/Correspondence Address Ates Kara Hacettepe Universitesi Tip Fakultesi, Cocuk Sagligi ve Hastaliklari Anabilim Dali, Cocuk Enfeksiyon Hastaliklari Bilim Dali, Ankara, Turkiye E-mail: ateskara@hacettepe edu tr Gelis Tarihi: 29 06 2020 Kabul Tarihi: 30 06 2020 Cevrimici Yayin Tarihi: 04 08 2020 ©Telif Hakki 2020 Cocuk Enfeksiyon Hastaliklari ve Bagisiklama Dernegi

Background/Objectives: Hand, foot and mouth disease (HFMD) has recently emerged as a serious health threat, as certain serotypes can cause severe illness. Serotype distribution vary by region, and seroprevalence studies helps in developing preventive strategies. This study aimed to determine the seroprevalence of enterovirus type 71 (EV-A71), Coxsackievirus A16 (CV-A16), Coxsackievirus A10 (CV-A10), and Coxsackievirus A6 (CV-A6), the main causative agents of HFMD and to investigate risk factors for seropositivity. Methods: This multicenter, cross-sectional study was conducted across five major cities in Türkiye. Children (6 months–17 years) who presented to outpatient clinics for any reason were included between May 2024 and January 2025. Neutralizing antibodies were measured using a microneutralization assay. Statistical analyses included descriptive methods, appropriate group comparisons (Chi-square/Fisher’s Exact), and backward logistic regression to identify factors associated with HFMD seropositivity. Results: The study included 998 participants (mean age: 8.6 ± 5.2 years; 51.3% male). CV-A6 antibodies were detected in 68.5%, EV-A71 in 66.5%, CV-A10 in 60.2%, and CV-A16 in 46.0% of samples. No viral antibodies were detected in 5.3% of serum samples (All-Negative group); antibodies against at least one HFMD agent were detected in 94.7% (Any-Positive group). HFMD seropositivity increased significantly with age. Handwashing habits did not differ between the groups. The any-positive group more often had a household member aged 12–18 years, a mother with lower education, and higher kindergarten attendance. In logistic regression analysis, age, average monthly household income, and mother’s education level were the factors influencing seropositivity. Conclusions: The seroprevalence of HFMD-causing viruses in Türkiye is high from six months of age onward. Beyond promoting personal protective measures, the implementation of a vaccination program should also be considered.

Measles remains among the most important global health threats worldwide. A global increase has been reported since 2022, peaking in 2024, which heightens the risk of imported infections, particularly from unvaccinated children and adults, and measles outbreaks persist where immunity gaps remain. The aim of this study was to assess the clinical severity, complications, and outcomes of measles in hospitalised children as well as the effect of vaccination status on measles in Türkiye in 2023. We performed a retrospective, multicentre cohort study that included 34 medical centres between 1 January and 31 December 2023. Children ≤ 18 years who were hospitalised with WHO-confirmed measles were included. A standard electronic case report form captured demographics, vaccination status, clinical features, complications, and outcomes. Our study outcomes included any major complication, severe disease defined as PICU admission, and in-hospital mortality. We also performed a secondary analysis of the differences in presentation, complications, therapy, and resource use according to vaccination status. A total of 504 children with measles were analysed (median age 26 months, IQR 9–88; 56.3

Infectious complications remain the major cause of treatment-related morbidity and mortality in pediatric patients with acute lymphoblastic leukemia (ALL). This study retrospectively compared the patterns of infection in children treated with either the modified St. Jude Total XV protocol (n = 181) or the ALL-IC BFM 2009 protocol (n = 61) at a single center. Although the overall number of infection episodes was similar between the two groups, their distributions across treatment phases differed markedly. The ALL-IC BFM 2009 protocol was associated with a significantly greater incidence of infections during the induction phase, particularly in high-risk patients, who often presented with skin and gastrointestinal tract infections. In contrast, modified St. Jude Total XV protocol presented a greater infection risk during the re-induction phase. Gram-positive bacteria, especially Staphylococcus epidermidis, were the most frequently isolated pathogens in both cohorts, although the BFM group exhibited a higher proportion of gram-negative infections. The rates of documented viral infections in BFM cohort and modified St. Jude Total XV cohort were 21.4 % vs 9.2 %, respectively. Invasive fungal infection rate was found as 6.7 % in the modified St. Jude group and 4.0 % in the BFM group is in line with the literature. Multivariate analysis confirmed that severe neutropenia and the presence of a central venous catheter were strong independent predictors of infection frequency. These findings underscore protocol-specific differences in infectious risk profiles and emphasize the importance of tailored supportive care strategies in the management of pediatric ALL.

Background The rapid spread of the SARS-CoV-2 virus has led to a global health crisis, necessitating swift responses in medical science, mainly through vaccination strategies. While short-term vaccine effectiveness is evident, immune protection's long-term effects and duration remain incompletely understood. Systematic monitoring of these responses is essential for optimizing vaccination strategies.Aims This study aimed to explore the durability of antigen-specific T and B cell responses and antibody levels up to 8 months post-immunization with the inactivated TURKOVAC vaccine in volunteers. Additionally, the impact of two versus three doses of vaccination on these parameters was analyzed.Methods Volunteers (n = 80) received two or three doses of TURKOVAC. Spike-specific B cells, CD4+ T cells, CD8+ T cells, and antibody levels were measured at multiple time points post-immunization.Results Spike-specific B cells remained elevated up to 8 months post-immunization. SARS-CoV-2-specific CD4+ and CD8+ T cells peaked at 4 months but declined thereafter. TURKOVAC resulted in durable antigen-specific humoral and cellular immune memory with distinct kinetics. Still, most assessments observed no significant differences between two and three doses, except for antigen specific-IL-2 and CD4+ LAMP1 responses.Conclusion TURKOVAC vaccination induces durable immune responses, with spike-specific B cells persisting up to 8 months and T cell responses peaking at 4 months before declining. These findings suggest that TURKOVAC contributes to long-term immune protection against SARS-CoV-2.

Background/Objectives: The rapid evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the emergence of variants with enhanced transmissibility and immune evasion, challenging existing vaccines. This study aimed to evaluate the immunogenicity and protective efficacy of inactivated bivalent vaccine formulations incorporating the ancestral SARS-CoV-2 strain (ERAGEM) with either Delta or Omicron (BA.5) variants. Methods: Bivalent vaccine formulations were prepared using beta-propiolactone-inactivated SARS-CoV-2 antigens and administered to K18-hACE2 transgenic mice. Following prime and booster immunizations, neutralizing antibody titers and viral loads were assessed through ELISA, microneutralization assays, and quantitative PCR. Mice were challenged with the respective variants, and the survival rates, temperature, and body weight changes were monitored for 21 days. Results: Both vaccine formulations elicited significant increases in neutralizing antibody titers post-booster immunization. The ERAGEM + Delta group demonstrated geometric mean titers (GMTs) of 6938.1 and 4935.0 for the ancestral and Delta variants, respectively, while the ERAGEM + Omicron (BA.5) group achieved GMTs of 16,280.7 and 24,215.9 for the ancestral and Omicron (BA.5) variants. Complete survival (100%) was observed in all the vaccinated groups post-challenge, with no detectable viral titers in the lungs and substantial reductions in the nasal turbinate viral loads compared to the unvaccinated controls. Conclusions: The bivalent inactivated vaccines demonstrated strong immunogenicity and complete protection against severe disease in preclinical models. These findings indicate the potential of bivalent vaccine strategies in addressing antigenic diversity and preparing for future pandemics caused by rapidly evolving pathogens.

Antibiotic-associated diarrhea (AAD) is one of the side effects that occur during and after antibiotic use. Some probiotics have strain-specific beneficial effects on AAD development when used in combination with antibiotics. The aim of this study was to evaluate the effect of Limosilactobacillus reuteri DSM 17938 on the prevention of AAD in children. This is a prospective, multicenter, randomized, double-blind, placebo-controlled clinical trial in Türkiye between 2017–2019, among outpatient children with acute otitis media (AOM) or acute rhinosinusitis (ARS). Group 1 (n = 330) received amoxicillin-clavulanate and L. reuteri DSM 17938 (2 × 108 CFU) and Group 2 (n = 324) received amoxicillin-clavulanate and a placebo during the antibiotic treatment or continued for 21 days after antibiotic cessation. The primary end point of this study was the percentage of children with AAD in the first 14, 21, and 56 days of follow-up. Secondary endpoints are the percentage of children with AAD regarding the AOM vs ARS, amoxicillin-clavulanate dose, age groups, and the comparison between 14- and 21-days use of L. reuteri. The percentage of children with AAD was significantly lower in the L. reuteri group compared to the placebo group at 14 days (7.9 https://clinicaltrials.gov/study/NCT02765217?term=NCT02765217 rank=1 ).

Objective: Streptococcus pneumoniae is a pathogen that causes widespread and contagious diseases and poses a serious global public health threat, especially for infants, children and the elderly in the first two years of life. S. pneumoniae is a bacterium that can colonize the nasopharynx of adults, especially children, and can cause acute otitis media, respiratory tract infections and even life-threatening invasive infections (serious clinical conditions such as sepsis and meningitis). Serotyping of S. pneumoniae plays a critical role especially in infection management, epidemiological studies and vaccine development. There are more than one hundred known serotypes of S. pneumoniae. Each serotype has different pathogenicity, prevalence, infectivity and antimicrobial resistance patterns. Understanding the serotype distribution is important for monitoring the prevalence of serotypes covered by existing vaccines in the community and for planning future vaccines. Material and Methods: Considering all these issues, this study aimed to develop a rapid and cost-effective analysis method for pneumococcal serotyping using Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) spectroscopy. For this purpose, four different S. pneumoniae isolates (serotype 3, serotype 19A, serotype 23B and serotype 9L) were provided by the General Directorate of Public Health. Cultivated bacterial isolates were incubated at 37 oC in a 5% carbon dioxide atmosphere for 24 hours. Then, these culture samples were analyzed using Shimadzu FTIR-ATR device and a method was developed to create a serotype library Results: According to the results obtained from FTIR-ATR spectra of different S. pneumoniae isolates, peaks between 3100 and 950 nanometers belong to different regions that can allow serotyping of S. pneumoniae bacteria. Because the peaks in these regions belong to carbohydrates, lipids, nucleic acids and proteins that can present the unique fingerprint of each serotype. Conclusion: However, since the changes between the peaks in all analyzed data were minimal, it was seen that the sensitivity of the methods in distinguishing serotypes was limited. On the other hand, the overlapping of the spectra in the analysis of the obtained data indicates the high reproducibility of the method.

Objective: Poliovirus is an enterovirus consisting of three serotypes that has caused serious epidemics throughout history. With the widespread use of vaccines, the global incidence has decreased significantly, and types 2 and 3 have been eradicated. The only subtype currently circulating is wild poliovirus type 1. Today, wild poliovirus is found only in Afghanistan and Pakistan, while circulating vaccine-derived poliovirus type 2 (cVDPV2) is the most common type worldwide. While most infections are asymptomatic or mild, a very small proportion can lead to paralytic polio. Diagnosis is made with stool samples in cases of acute flaccid paralysis, and treatment is supportive. Oral and inactivated polio vaccines are used to prevent the disease, and novel oral polio vaccine type 2 is used for cVDPV2 outbreak control when necessary.