Pediatric Infectious Disease Journal

The evolving epidemiology of COVID-19, driven by successive SARS-CoV-2 variants of concern (VOCs), has prompted ongoing evaluation of their impact on disease severity in children. In low- and middle-income countries (LMICs), children experience a higher burden of severe respiratory illness and pneumonia-related mortality due to factors such as malnutrition, incomplete immunisation, HIV exposure or infection, tuberculosis, and disparities in access to healthcare services. Hospital-based paediatric studies from LMICs are therefore needed to understand how the epidemiology and severity of COVID-19 have changed across pandemic waves. This study examined 354 hospitalised children with SARS-CoV-2 infection during the ancestral, pre-Omicron (Beta and Delta), and Omicron waves at Tygerberg Hospital in Cape Town, South Africa. We analysed data collected over an extended period, from March 2020 to June 2022. Statistical analyses were used to describe clinical characteristics across variant periods, and multivariable logistic regression models were applied to evaluate associations between potential risk factors and disease severity. Paediatric COVID-19 severity varied across VOC periods, with the highest burden observed during the pre-Omicron (Beta and Delta) waves. In multivariable analyses, younger age and circulating variants were associated with disease severity; CRP levels emerged as a marker associated with more severe illness, and corticosteroid treatment, while also associated with disease severity, reflects clinical response to more severe cases. These findings contribute to a better understanding of the epidemiology and clinical impact of COVID-19 in children and highlight the importance of context-specific surveillance and treatment strategies in resource-limited settings.

Background Risk stratification tools for childhood pneumonia have been proposed to improve identification of children at highest risk of death, particularly in low-resource settings. However, their added value over the WHO Integrated Management of Childhood Illness (IMCI) criteria and danger signs remains uncertain. Methods We conducted a secondary analysis of a multi-country randomised controlled trial of children without HIV hospitalised with pneumonia in Mozambique, South Africa, Uganda, Zambia, and Zimbabwe. We evaluated the performance of five published risk scores alongside WHO IMCI severity classification and danger signs. Discrimination for (1) in-hospital mortality, (2) 28-day mortality, and (3) 28-day readmission or death was assessed using area under the receiver operating characteristic curve (AUC). Comparative performance and clinical utility were examined. Results Of the 1010 participants, 18 (1.8%) died in hospital, 22 (2.2%) died in hospital or in the 7 days post-discharge, and 63 (6.2%) died or were readmitted by day 28. Univariate case-fatality rates were highest for variables associated with malnutrition, convulsions, and hypoxaemia. All risk scores demonstrated moderate discrimination for in-hospital and in-hospital+7-day mortality (AUC range approximately 0.75-0.84), with no meaningful differences between models, and performed similarly to the WHO danger signs and IMCI severity classification. In contrast, all approaches performed poorly in predicting 28-day readmission or death (AUC approximately 0.54-0.58). No risk score consistently outperformed simple clinical criteria. Conclusions In this multi-country dataset, we found no evidence that published paediatric pneumonia risk scores meaningfully outperform WHO IMCI-based clinical assessment for predicting mortality. The relatively small number of mortality events limits precision, and modest differences cannot be excluded. These findings suggest that, in low-resource settings, strengthening implementation of existing WHO clinical criteria may be more effective than adopting more complex prediction tools.

Background Despite cerebrospinal fluid (CSF) analysis being the gold standard for definitively diagnosing meningitis, its practical application has presented considerable difficulties, especially in environments with limited resources. Cranial ultrasound (CUS), while not a replacement for CSF analysis, provides rapid imaging to identify meningeal irregularities. Nevertheless, achieving a timely diagnosis of meningitis, particularly in its nascent stages, remains problematic, and healthcare professionals exhibit a notably low awareness of CUS's utility in diagnosing this condition. Methods This was a prospective cohort that recruited 273 term mother-neonate pairs. The neonates were initially divided into those with sepsis-meningitis (exposure group) and those with sepsis (non-exposure group) based on clinical assessment done by the admitting team. The research team further divided the participants into 4 diagnostic subgroups based on CUS findings: positive CUS for meningitis, positive clinical diagnosis for meningitis, positive CUS & clinical diagnosis for meningitis and those with negative CUS & clinical diagnosis for meningitis /sepsis only. Data on socio-demographics, clinical characteristics, blood works and CSF analysis reports, neurologic deficits and mortality outcomes were recorded for each neonate. Descriptive and inferential statistics were performed. Results The 4 diagnostic subgroups based on CUS findings were: positive CUS for meningitis (24.5%), positive clinical diagnosis for meningitis (4.4%), positive CUS & clinical diagnosis for meningitis (6.6%) and those with negative CUS & clinical diagnosis for meningitis /sepsis only (64.5%). Overall, duration of hospitalization was 11 days (range 2-45 days; interquartile range [IQR] 6,16) and the median chronological age of the neonates was 13 days (IQR 7, 21). Meningitis was suspected in 11% of neonates admitted with clinical sepsis. Uptake for lumbar puncture (LP) or ventricular tap (VT) was low at 4.4% (n = 12), underlining barriers to CSF-based diagnosis in this setting. Late-onset sepsis was associated with only 31.9% of NSM. The chronological age of the neonates at admission (p=0.002) and their duration of hospitalization (p=0.042) were significantly different across the 4 categories of neonates. Prominent sulci, hyperechoic brain lesions, ventriculitis, and lateral ventriculomegaly were the most common abnormal findings on CUS. Overall, neonates with meningitis presented later in age and stayed longer on the ward than those with sepsis: clinical meningitis diagnosis was likely to be made in older neonates and was associated with a shorter duration of hospitalization than CUS-diagnosed meningitis. Overall mortality rate was 2.2%. Mortality (16.7%) was highest amongst those with clinical & CUS diagnosed-NSM. Prevalence of Near-Miss cases of NSM was at least 27.6%. A neonate with clinical diagnosis of NSM was 3.94 times (95% CI 1.80, 8.62; p<0.001) more likely to have abnormal CUS at the time of admission. Percent agreement between the clinical and CUS diagnosis for NSM was 71.1%. Nine (75%) out of the 12 CSF reports was positive for meningitis; and the majority 55.6% (5) of the positive CSF report belonged to the category of neonates with sepsis only. Compared to CSF analysis, sensitivity of clinical diagnosis of NSM was 22.2%; specificity was 33.3%; positive predictive value (PPV) was 50%; negative predictive value (NPV) was 12.5% and likelihood ratio (LR) was 0.33. Whereas, sensitivity of CUS was 44.4%; specificity of CUS was 66.7%; PPV was 80%; NPV was 28.6% and LR was 1.33. Conclusion The CUS was only moderately effective at diagnosing meningitis whereas the presence of positive CSF among neonates with sepsis only within this study, further reaffirms the irreplaceability of CSF analysis in the diagnosis of NSM. Nevertheless, the integration of clinical assessment and CUS findings for diagnosing NSM emerged as possessing greater clinical significance in contexts characterized by limited resources. The systematic adoption of CUS for neonates exhibiting features suggestive of sepsis or meningitis (while exploring measures to improve on uptake of CSF analysis) could enhance the promptness of diagnosis, inform the selection of suitable therapeutic interventions, and potentially mitigate mortality rates and the occurrence of long-term neurological impairments, especially within environments facing resource limitations.

Background Otitis media is a leading cause of childhood morbidity and presents a significant healthcare burden worldwide. Streptococcus pneumoniae is a major aetiological agent of OM, and the introduction of pneumococcal conjugate vaccines into the Malaysian National Immunisation Programme in 2020 would have altered pneumococcal carriage and serotype distribution. This study aimed to determine pneumococcal carriage, serotype distribution, and associated risk factors among children with OM in the early post-PCV era in Peninsular Malaysia. Methods and Findings A total of 360 children with OM were recruited from hospitals on the east and west coasts of Peninsular Malaysia between 2023 and 2025. Nasopharyngeal and middle ear fluid samples were collected for Spn isolation by culture, followed by serotyping using multiplex PCR. Sociodemographic, environmental, and medical history data were analysed for associations with pneumococcal carriage using chi-square, Fishers exact tests, and logistic regression. Pneumococcal carriage was detected in 26.7% of children in either NP or MEF samples, with carriage rates of 25.6% and 1.9% in NP and MEF samples, respectively. The most prevalent serotypes were 23A, 15B/15C, non-typable strains, 19F, and 11A/11D. Daycare attendance (p = 0.012, aOR [95% CI]: 2.177 [1.186 - 3.995] and residence in rural areas (p = 0.019, aOR [95% CI]: 2.476 [1.159 - 5.292] were significantly associated with pneumococcal carriage. The main limitation of the study was the reliance on self-reported questionnaire data, which may have introduced recall bias and reporting errors. Conclusions The predominance of non-vaccine serotypes and non-typable Spn indicates ongoing serotype replacement and the emergence of phase-variant strains in the early post-PCV era. Continued surveillance is essential to monitor these changes and inform the development of next-generation pneumococcal vaccines. This study was registered under clinical trial registration number NCT05429541.

Background Klebsiella pneumoniae is a leading cause of sepsis in young infants. We evaluated the association of invasive K. pneumoniae disease (iKPnD) in relation to antigen-specific immunoglobulin G (IgG) and serum bactericidal activity (SBA) to four polysaccharide capsular (K) serotypes and five lipopolysaccharide (O) serotypes, as well as IgG to MrkA, in infants less than 90 days of age. Methods We conducted a retrospective case-control study in Kenyan and South African infants with blood culture-confirmed iKPnD. Serotype-specific antigen IgG concentrations of cases were compared with hospitalised controls without iKPnD. Geometric mean concentrations (GMCs) were estimated, and scaled covariate-adjusted models were used to estimate risk reduction over a grid of antibody concentrations. Results Transplacental transfer of IgG against various K. pneumoniae antigens increased with advancing gestational age. Serum IgG GMCs (expressed in RLU/mL) to disease-causing homotypic K- or O-serotypes were lower in cases compared with controls for anti-K2 (396 [95%CI: 250-628] vs 660 [95%CI: 562-776]), anti-K25 (396 [95%CI: 251-623 ] vs 1170 [95%CI: 988-1385]), anti-K149 (327 [95%CI: 204-521] vs 492 [95%CI: 435-557]); as well as anti-O1{beta},2 IgG (1282 [95%CI: 782-2101] vs 2250 [95%CI:1904-2658]). Furthermore, overall anti-MrkA IgG was lower in cases (945; 95%CI: 757-1179) compared with controls (1610; 95%CI: 1378-1880). SBA titres (expressed as IC50) did not differ between case and controls by K types, but were lower for O1{beta},2{beta} in cases (27; 95%CI: 12-63 vs. 136; 95% CI: 84-221). Conclusion Our findings provide preliminary evidence that low antibodies against three of four K-antigens, O1{beta},2{beta} and MrkA are inversely associated with iKPnD, and should be explored as potential vaccine antigens.

Background: Neonatal meningitis and pneumonia are important causes of morbidity and mortality among hospitalized newborns in low-resource settings. Numerous single-centre studies have been conducted in Ethiopian public hospitals, yet no quantitative synthesis of neonatal meningitis prevalence previously existed, and the depth of the pneumonia-specific evidence base was undocumented. This review aimed to estimate the pooled prevalence of neonatal meningitis, and to establish the state of the evidence base for neonatal pneumonia, among neonates treated at public hospitals in Ethiopia. Methods: A systematic search of PubMed/MEDLINE, PubMed Central, PLOS, BioMed Central, Frontiers, Taylor & Francis Online, and institutional repositories was conducted without date restriction. Cross-sectional and retrospective studies reporting a standalone prevalence of neonatal meningitis or neonatal pneumonia among neonates treated at Ethiopian public hospitals were eligible. Methodological quality was appraised using the JBI Critical Appraisal Checklist for prevalence studies. A random-effects meta-analysis pooled meningitis prevalence; heterogeneity was quantified with I2 and Cochran's Q. Results: Of 26 full-text articles assessed for eligibility, four studies (N = 3,522 neonates) met inclusion criteria for neonatal meningitis; none met inclusion criteria for a standalone neonatal pneumonia prevalence outcome. The pooled prevalence of neonatal meningitis was 6.26% (95% CI: 2.81-13.35%; I2 = 96.6%), with individual study estimates ranging from 1.73% to 19.30%. A sensitivity analysis restricted to the three studies using a "suspected-meningitis" denominator yielded a pooled prevalence of 4.23% (95% CI: 1.92-9.05%). No eligible primary study reported neonatal pneumonia prevalence as a standalone, separately ascertained outcome across the accessible literature, pneumonia is consistently subsumed within composite "neonatal sepsis" case definitions. Conclusion: An estimated 1 in 16 to 1 in 24 neonates tested for suspected meningitis at Ethiopian public hospitals had a culture-confirmed or clinically diagnosed case, with wide variation across settings and case-ascertainment methods. A previously undocumented evidence gap exists for standalone neonatal pneumonia prevalence in Ethiopia. Future primary studies should report pneumonia as a distinct, separately ascertained neonatal outcome to enable future quantitative synthesis.

Background. Obesity has been associated with higher risk of dengue virus (DENV) infection and disease, yet its influence on antibody responses to DENV remains undefined. Methods. We evaluated whether nutritional status -- based on BMI z-score (BMIz) -- or blood markers of body fat -- leptin and adiponectin --are associated with binding and/or neutralizing antibody responses to DENV in 85 children in the Nicaraguan Pediatric Dengue Cohort Study who experienced a primary DENV infection in 2019. Associations were estimated using linear models adjusting for age, sex, and DENV infection outcome. Results. Compared to children with normal weight, those with obesity had higher quantities of DENV binding antibodies (fold-change [FC] 1.89, 95% confidence interval [CI] 1.02, 3.48) but no difference in neutralizing antibodies. Likewise, leptin concentration was associated with higher quantities of binding antibodies (FC 1.22, 95%CI 1.09, 1.37), while adiponectin was associated with lower quantities (FC 0.79, 95%CI 0.67, 0.94), and neither was associated with neutralizing antibodies. Lower neutralizing efficiency (neutralizing/binding antibodies) was observed in children with obesity (FC 0.67, 95%CI 0.48, 0.93). Conclusions. Our results indicate that obesity is associated with higher antibody quantity (binding) but not higher quality (neutralization) post-primary DENV infection -- implying that antibodies generated by children with obesity have lower neutralization efficiency, requiring greater quantities to reach similar levels of neutralization than children with normal weight. Further, the agreement among the three models using distinct proxies of body fat -- BMIz, leptin, and adiponectin -- demonstrates that adipokines are useful in supplementing BMIz analysis or as independent predictors of immune responses.

Background: Vitamin K prophylaxis is universally recommended for newborns to prevent life threatening vitamin K deficiency bleeding. Although not on the immunization schedule, vitamin K prophylaxis is often coadministered with hepatitis B birth dose and erythromycin ophthalmic ointment, and rising hesitancy around vaccines/preventive care may spill over into vitamin K administration. Methods: We conducted a retrospective cohort study using Truveta electronic health record data with linked mother-child dyads. Live births to mothers aged 15-49 from January 1, 2019 through June 30, 2026 were included. Vitamin K administration was defined as documentation on the birth date or following day. Logistic regression assessed sociodemographic predictors of non-receipt, and interrupted time series analysis evaluated changes after January 2026. Results: Among 1,026,375 infants, 995,628 (96.97%) had documented vitamin K administration. Non-receipt increased from an average of 2.1% during 2019-2022 to 4.3% in 2025 and 6.1% in 2026, reaching 8.10% in June 2026. Older maternal age, non-Hispanic or Latino ethnicity, Medicaid or unknown insurance, and year of delivery were associated with greater odds of non-receipt. After January 2026, there was no immediate step change, but the odds of vitamin K receipt declined an additional 10% per month (OR: 0.90; 95% CI, 0.88-0.91). Conclusions: Vitamin K non-receipt increased over the study period and accelerated after January 2026. Because vitamin K recommendations were not changed by the January vaccine schedule, this association may reflect broader impacts to confidence in newborn preventive care. Future studies should examine causal mechanisms, parental decision-making, and associated clinical outcomes.

In newborns seen a median of 11 days after birth, 97/1699 (5.7%) had conjunctivitis, including 13/97 (13.4%) with Chlamydia trachomatis or Neisseria gonorrhoeae detected. Among all babies, we estimated that 6.6% (95% confidence interval 3.8-9.9%) would have C. trachomatis or N. gonorrhoeae detected, of which 87.0% (74.8-93.8%) would be asymptomatic.

Rationale: Infections due to Extended-spectrum {beta}-lactamases-producing Enterobacterales (ESBL-PE) require empirical treatment with carbapenems. ESBL-PE carriage is considered as a risk factor for ESBL-PE involvement during ICU infection. Our aim was to determine factors that may predict the actual involvement of ESBL-PE. Methods: A two-periods bicentric ambispective study including ICU ESBL-PE carriers patients from April 2011 to January 2019. All ESBL-PE carriers who developed an infection were analyzed. Results: 6112 patients and 4902 patients were screened during the two periods. 384 and 232 ESBL-PE carriers were identified. Total number of infectious episodes were 146 and 114, respectively. A total of 144 pneumonias, 42 urinary tract infection and 45 digestive infections were studied. An ESBL-PE was involved in 35 (24.3%) episodes of pneumonia, and 44 (37.9%) of extra-pulmonary infections. The most frequent ESBL-PE involved were K. pneumoniae, E. cloacae and E. coli. Similar species and phenotypes were present in colonisation and infection in 29 (82.8%) of pneumonia and in 40 (90.9%) of extra-respiratory infection. Multivariate analysis identified Klebsiella pneumonia or Enterobacter cloacae carriage as risk factor for ESBL-PE involvement in pneumonia and E. coli carriage and detection of ESBL-PE carriage before ICU admission as protective factors. Conclusion: In our study an ESBL-PE involvement is infrequent in pneumonia. A known carriage before ICU admission and E. coli carriage are factors associated with the absence of ESBL-PE un the episode of respiratory infection. A confirmation of our findings could lead to a reduction in the empirical use of carbapenems in this population.

Importance: Respiratory syncytial virus (RSV) hospitalization rates are highest among children <2 years of age. RSV immunization with infant monoclonal antibody or maternal vaccine is recommended to protect all U.S. infants in their first RSV season. For certain high-risk children aged 8-19 months entering their second RSV season, the monoclonal antibody nirsevimab is recommended. Little is known regarding preexisting health conditions as risk factors for RSV-associated respiratory failure in children during their second season. Objectives: To describe children admitted to the pediatric intensive care unit (PICU) for RSV during their second RSV season by preexisting health conditions, and to compare demographic and clinical characteristics across groups. Design, Setting, and Participants: Surveillance registry of children 8- <24 months old admitted to the PICU in 30 pediatric hospitals in the 2023-2024/2024-2025 RSV seasons. All children had an RSV-positive respiratory sample and received respiratory support with high flow nasal cannula, noninvasive ventilation, or invasive mechanical ventilation (IMV). Exposure: Preexisting health conditions potentially increasing risk of severe RSV disease. Main Outcomes and Measures: Patients were classified into four mutually exclusive groups by preexisting health conditions: 1) U.S. nirsevimab eligible criteria, 2) other identified RSV risk conditions (with some evidence of increased risk for severe RSV), 3) other preexisting conditions, and 4) no preexisting conditions. Patient demographic characteristics and level of respiratory support received were compared. Results: Among 574 children: 47 (8.2%) had U.S. nirsevimab eligibility criteria, 76 (13.2%) had other RSV risk conditions, 96 (16.7%) had other preexisting conditions, and 355 (61.8%) had none. A higher proportion of children with nirsevimab eligibility factors (40.4%) than those with other identified RSV risk conditions (17.1%) required IMV, which was higher than other (10.4%) or no (5.9%) preexisting health conditions (ptrend<0.001). Conclusions and Relevance: Approximately 20% of children admitted to the PICU with severe RSV were in the defined groups that met U.S. nirsevimab-eligibility criteria or that had an identified RSV risk condition associated with known risk for severe RSV. A considerable proportion of both groups of children required IMV for respiratory support. These findings may help inform future deliberations regarding U.S. second season nirsevimab-eligibility recommendations.

Background: Risk adjustment for disease severity in pediatric intensive care research commonly relies on clinical organ dysfunction scores requiring detailed clinical and laboratory information, which is often unavailable in administrative healthcare datasets. We therefore evaluated the feasibility of a coding-based Pediatric Organ Dysfunction Index (PODI) derived from International Classification of Diseases (ICD-10) and Operation and Procedure System (OPS) codes, for approximating sepsis-related organ dysfunction and adjusting for disease severity, using the pediatric Sequential Organ Failure Assessment (pSOFA) score as a reference standard. Methods: In this retrospective single-center cohort study, pediatric sepsis episodes treated between November 2011 and November 2021 were identified. Discrimination for in-hospital mortality and calibration were assessed. Agreement between PODI and pSOFA was quantified using Spearman's rank correlation, and organ-specific agreement using sensitivity, specificity, and predictive values. An expanded PODI incorporating additional ICD-10 and OPS codes was evaluated in sensitivity analyses. Results: A total of 488 pediatric sepsis episodes were included, with an in-hospital mortality of 14.1%. The PODI showed good discrimination for in-hospital mortality (AUC 0.85, 95% CI 0.80-0.89), comparable to the maximum pSOFA (pSOFAmax) (AUC 0.78, 95% CI 0.72-0.83) and superior to pSOFA at sepsis onset (pSOFAonset) (AUC 0.73, 95% CI 0.67-0.80). Agreement between PODI and pSOFA organ-specific components varied considerably across organ systems, with the highest sensitivity to detect pulmonary dysfunction. Correlation between both scores was moderate (0.54 for pSOFAonset and 0.60 for pSOFAmax), indicating that comparable predictive performance does not render the scores interchangeable. The expanded PODI improved organ-level sensitivity for selected components but did not meaningfully improve mortality discrimination. Conclusions: The standard PODI may represent a practical approach to adjust for organ dysfunction and therapy intensity in administrative datasets with ICD-10 coding where clinical and laboratory information is unavailable. Given only moderate agreement with the pSOFA, the PODI should be understood as a covariate for risk adjustment at the group level rather than as a substitute for clinical organ dysfunction scores in individual patients. Further validation and refinement in non-sepsis cohorts are required before broader implementation in large-scale administrative research can be recommended.

Enteric pathogen infections are a major global health challenge, influenced by a variety of host and environmental factors, and their clinical presentation and treatment can be complicated by the presence of co-infections. The prevalence of enteric infections and co-infections tend to vary between rural and urban contexts, likely driven by underlying environmental, geographic, and demographic characteristics. To improve understanding of urbanicity and age on enteric pathogen prevalence and on co-infection risk, we measured 22 enteric pathogens in fecal samples collected from children aged 6, 12, and 18 months across a rural-urban gradient within the ECoMiD birth cohort study (n=473). Enteric pathogen burden was high and increased with age, with at least one pathogen detected in 91% of children at 6 months, 97% at 12 months, and 98% at 18 months. However, prevalence of some pathogens-- notably Salmonella enterica, enterovirus, and rotavirus-- decreased with age. Co-infections were also common (88%), and children were infected with as many as 11 pathogens simultaneously. The most frequently observed co-infection profiles included enteroaggregative E. coli and atypical enteropathogenic E. coli, followed by combinations with diffusely adherent E. coli, enterovirus, enterotoxigenic E. coli, and/or adenovirus. Enteric pathogen detection generally was higher in more rural settings, though patterns varied by pathogen. These results provide useful information for future examination of pathogen dynamics of co-occurrence. Given the ubiquity of enteric infections in high transmission settings, strategies that aim to reduce overall microbial exposure may be needed to supplement interventions targeting control of individual pathogens.

Objectives. Perinatal illness and preterm birth carry lifelong multiorgan complications and are associated with hematologic derangements during neonatal intensive care unit (NICU) admission. Despite this, long term hematologic morbidities following neonatal critical illness remain undefined. Our objective was to identify associations between prematurity, perinatal critical illness, and later hematologic dysfunction. Study design. Single neonatal care network retrospective cohort study with cohorts divided by gestational age and the presence of critical illness markers. The association between hematologic dysfunction, critical illness, and prematurity was investigated using multivariate logistic regression. Results. Among 13073 infants, critical illness or prematurity was found to increase the odds of developing pancytopenia post-NICU discharge. Subsequent analyses stratified on prematurity demonstrate that a diagnosis of shock or sepsis was associated with pancytopenia. Conclusions. Our findings suggest that perinatal insults are associated with hematopoietic system dysfunction and long term morbidity. Importantly, critical illness, not prematurity itself, may drive this association in preterm infants.

Background: Repeated enteric infections and chronic enteric dysfunction have been associated with undernutrition in children. Interventions that reduce enteric pathogen exposure in young children could thereby improve growth and developmental outcomes. We assessed enteric pathogen prevalence in Bangladeshi infants, the impact of a combined homestead food production and food hygiene intervention on pathogen infections, and associations between pathogen infections, enteric dysfunction markers, and child growth outcomes. Methods: We analyzed panel data from 231 children born between April and December 2018 within the Food and Agricultural Approaches to Reducing Malnutrition (FAARM) cluster-randomized trial in Sylhet, Bangladesh. Stool samples were collected at 0-3, 6-8, and 10-13 months of age and assessed for enteric dysfunction biomarkers (myeloperoxidase, alpha-1 antitrypsin, and neopterin) by ELISA and 14 enteric pathogens by multiplex RT-PCR. Diarrhea prevalence was recorded using 7-day recall. Child length and weight were measured at birth and trial endline. Multilevel regression assessed the intervention effect and quantified associations between pathogen exposure, enteric dysfunction, and growth outcomes. Findings: Enteric pathogen prevalence was high (84%) despite low 7-day diarrhea prevalence (5%), and co-infections were common. There was no intervention effect on the prevalence of enteric pathogens. Shigella spp. and Giardia lamblia were associated with higher myeloperoxidase concentrations, while sapovirus was associated with higher alpha-1 antitrypsin concentrations. Repeated protozoan infections (mainly Giardia lamblia) were associated with lower length-for-age, while repeated viral infections (mainly rotavirus and sapovirus) and Cryptosporidium infections were associated with lower weight-for-height and weight-for-age. There was marginal evidence that bacterial infections were associated with lower length-for-age. Conclusion: The intervention was insufficient to reduce the high burden of enteric pathogens in infants, and subclinical infections were associated with enteric dysfunction and poorer growth outcomes. Comprehensive strategies addressing all key exposure pathways are needed to limit pathogen infections and their consequences for child development.

Background Klebsiella pneumoniae (Kpn) is a major cause of neonatal sepsis in Africa. 3rd generation cephalosporin and gentamicin resistant Kpn is the norm in many sites, rendering WHO recommended first- and second-line antimicrobials ineffective. An understanding of which neonates and infants are most at risk of sepsis caused by Kpn would support the case for improved access to WHO watch and reserve antimicrobials (i.e. carbapenems) for patients most likely to benefit from them. Methods A prospective case-control study was conducted at Queen Elizabeth Central Hospital, Malawi. Cases were infants <3 months of age with blood or CSF culture confirmed Kpn infection. Controls were healthy infants from the same wards and were matched 2:1. Univariate and multivariate logistic regression were performed on mean-centred data to determine risk factors for infection with Kpn. Results We analysed data from 38 cases and 76 controls between August 2021 and April 2023. Mortality at 3 months of age was 21/38 (29%) for cases, with 14/38 (37%) identified postmortem and 6/76 (7.9%) for controls (OR 14.0 (95% CI 4.59, 49.2, p>0.001). Cases were more likely to be born out of QECH than controls (42% vs. 24%, p = 0.043), and cases had lower birthweights (median 2200g vs. 2850g, p = 0.005). Multivariate logistic regression analysis revealed that increasing birthweight was protective against Kpn infection (OR: 0.858 [95% CI: 0.745, 0.987] per 100g increase), while longer hospital stay was associated with increased odds of infection (OR: 1.148 [95% CI: 1.012, 1.1.303] per additional day). Most infecting isolates (34/38 [89%]) were resistant to first- and second-line antimicrobial agents, but all were sensitive to meropenem and 33/36 [92%] to amikacin. Conclusion Low birthweight infants with prolonged hospital stay were at greatest risk of Kpn infections that were typically resistant to WHO first- and second-line antimicrobial therapy. These infants should be prioritised for antibiotics that have the potential to be life-saving. The overlapping and evolving nature of these risk factors makes it difficult to design a simple tool to support empiric initiation of meropenem. Neonates critically ill with Kpn sepsis cannot, however, afford to wait for blood culture confirmation before receiving effective treatment. This highlights the need for empiric decision making frameworks that allow rapid initiation of effective therapy in high-risk neonates.

Background: Refractory and macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) has emerged as a major challenge in pediatric respiratory medicine, amplified by the post-2023 resurgence. However, a systematic overview of the research landscape specific to treatment-refractory and drugresistant disease in children remains lacking. Methods: Research articles and reviews on pediatric refractory or macrolide-resistant MPP published between 2000 and 2025 were retrieved from OpenAlex using Boolean searches. After screening, 2,286 records were quantitatively analyzed for annual output, contributing countries/institutions, thematic clusters, and citation-burst dynamics using Python. Results: Annual publications grew exponentially, with a pronounced surge after 2023 (n=378 in 2025). China produced the highest volume (45.1%) but recorded fewer citations per publication than the US, Japan, and Canada. The literature resolved into four clusters: macrolide resistance/molecular basis, epidemiology, etiology/co-infection, and refractory disease management. Burst analysis showed an evolution from earlier fronts like 23S rRNA mutations and azithromycin to recent emerging trends like pandemic-related co-circulation, genotype surveillance, and co-infection. Conclusions: Research on pediatric refractory and resistant MPP is expanding rapidly, shifting in emphasis from etiologic descriptions toward resistance mechanisms and clinical management. Standardizing the treatment of macrolide-unresponsive disease and post-pandemic epidemiological surveillance represent the principal directions for future work. Keywords: Mycoplasma pneumoniae; children; macrolide resistance; refractory pneumonia; bibliometric analysis; research trends

Background Obtaining uncontaminated urine samples from children can be difficult. Clean catch urine (CCU) is non-invasive but may be slow and lead to a contaminated sample, whereas transurethral bladder catheterisation (TUBC) and suprapubic aspiration (SPA) are invasive. We assessed the feasibility of randomising children to a definitive trial. Methods FROG was a multicentre, randomised feasibility trial with a mixed-methods perspectives study, health-economic analysis and stakeholder consensus meeting. Children under 16 years requiring urine testing for suspected urinary tract infection (UTI) who could not provide a midstream sample were eligible for the feasibility trial. Parents, children and healthcare professionals were eligible for the perspectives study and consensus meeting. Results Of 703 children screened, 170 were offered the study and 99 were recruited. Overall, 64/170 (37.6%) consented to randomisation, exceeding the feasibility threshold (33%); 32 were allocated to CCU and 32 to TUBC. The allocated method was received by 46/64 (71.9%); delays, unsuccessful collection and distress contributed to non-receipt. Among participants with available cultures, contamination occurred in 2/12 (16.7%) allocated CCU and 0/6 allocated TUBC. No participants consented to randomisation involving SPA. The perspectives study included 14 parent interviews, 89 parent questionnaires and 28 staff across 5 focus groups and 1 interview. CCU and TUBC were considered acceptable, although participants balanced speed and accuracy against pain and distress. SPA availability and acceptability were limited. A total of 19 stakeholders attended the consensus meeting; 94% supported recruiting children aged under 18 months and 100% supported comparing CCU with TUBC, without SPA. Accuracy was the highest-ranked outcome. Conclusions A definitive trial comparing CCU-first with TUBC-first in children aged under 18 months is feasible. Its primary outcomes should reflect diagnostic accuracy and clinical consequences of contamination, with successful collection, collection time, pain and distress assessed as key secondary outcomes.

Background Serosurveillance can estimate the prevalence of antibodies (Ab) acquired through vaccination or current and/or past infection. Multi-pathogen serosurveillance that measures multiple Ab simultaneously, can enable identification of vulnerable sub-populations with immunity gaps to vaccine preventable diseases (VPD) and concurrent burden of neglected tropical disease (NTD), including those nearing elimination (lymphatic filariasis [LF], trachoma) and eradication (yaws). This study aimed to estimate seroprevalence and identify temporal trends of selected VPDs and NTDs in Samoa to inform targeted public health action. Methodology/Principal Findings Dried blood spots were collected from four repeated community-based surveys in eight primary sampling units (PSU) in Samoa in 2018, 2019, 2023 and 2024. Multiplex bead assays were used to detect Abs against antigens (Ag) for diphtheria, measles, rubella, tetanus, LF [Wb123 or Bm14], yaws [both Rp17 and TmpA; <14 years only], and trachoma [Pgp3; <14 years only]. Seroprevalence estimates were adjusted for sampling design and standardised for age and sex. Overall, 2,871 participants were included in this analysis. Seroprevalence of measles increased from 42% in 2018 to 95% in 2024, whereas diphtheria decreased from 79% in 2018 to 65% in 2024. Seroprevalence to yaws remained <1% for all years, whereas trachoma decreased from 21% to 7% (2018-2024). LF seroprevalence decreased between 2018 and 2024 for Bm14 (37% to 9%) and increased for Wb123 (10% to 22%). This study identified 15 (0.5%) individuals who were seronegative to all VPDs (7 in 2018; 8 in 2019); of these, five were seronegative to all VPDs and seropositive to at least one NTD. Conclusions/Significance Identification of sub-populations with concurrent seronegativity to VPDs and seropositivity to NTDs underscores the potential role of multi-pathogen serosurveillance in directing public health interventions to those at greatest risk. Examination of temporal patterns offer a valuable tool for measuring intervention impacts and progress towards elimination goals.

Background: Mortality and hospital admissions due to Severe Acute Respiratory Infection (SARI) peaked between January and August 2025 in Brazil. Methods: The Brazilian Ministry of Health data on hospital admissions and deaths caused by SARI were compiled by age group (<5, 5-14, 15-49, 50-64, 65+ years) and quarter between January 2023 and June 2025. SARI causes were aggregated into SARS-Cov-2, Influenza, Respiratory Syncytial Virus (RSV), and other viruses (parainfluenza, adenovirus, rhinovirus, bocavirus, metapneumovirus). Multinomial regression was used to impute likely causes of death when these were not laboratory confirmed. Results: In the second quarter of 2025 (2025/2), RSV mortality rate among children <5 years reached 60 per 100,000, which is a 43% increase compared with 2024/2. Mortality rate for the joint impact of parainfluenza, adenovirus, rhinovirus, bocavirus, and metapneumovirus in the same age group doubled from 20 to 40 on the same scale in 2025/2 compared to 2024/2. Over the same period, influenza mortality tripled among the aged, whereas mortality due to other respiratory viruses increased less dramatically, except for SARS-CoV-2, which decreased among the aged from 150 to 25 per 100,000 between 2023/1 and 2025/2. Other age groups remained relatively stable over the period. The variation in hospital admissions largely followed that of mortality. Conclusions: While deaths and hospital admissions caused by SARS-CoV-2 declined rapidly since 2023, mortality rates of other respiratory viruses, mainly influenza and RSV, increased significantly among children <5 years and the aged in 2025/2. Public health policies that facilitate vaccine uptake against these infections should be given high priority.