This study analyzes the strategies of the World Health Organization (WHO) and the Pan American Health Organization (PAHO) to promote access to COVID-19 vaccines in Latin America and the Caribbean, exploring the vaccines administered, vaccination coverage in the countries, and inequalities in vaccination in the region. The study method combines analysis of secondary data and of documents, and interviews with key informants. The results show advances and limitations of the WHO and PAHO initiatives to promote vaccine equity, adopt redistributive measures to reduce inequalities in access to vaccines, and achieve the established global coverage goals. This study identified structural and political-institutional factors that favored or hindered the action of these organizations in vaccine distribution and promotion of vaccination equity during the pandemic. The role of these multilateral organizations in global and regional health arrangements is critically discussed in terms of their legitimacy, institutional capacity, and technical competence. The conclusions highlight the importance of strengthening mechanisms of global solidarity and helping Latin American nations overcome structural problems, such as limited national production and scientific and technological dependence, which hampered vaccination processes and aggravated inequalities between countries during the health emergency.

The article analyzes health policies in Brazil from 2016 to 2022, a period marked by a shift in national politics and the COVID-19 pandemic. The study examines federal health policy management under the administrations of Michel Temer (2016-2018) and Jair Bolsonaro (2019-2022), considering the context, the political process, and policy content, as well as the different phases of the pandemic response. Drawing on historical institutionalism and the concept of critical juncture, the analysis explores continuities, changes, and disputes surrounding the Brazilian Unified National Health System (SUS). The study drew on document research, news articles, and the academic literature. The results indicate that the period was a critical juncture, with immediate and severe effects on policy implementation and the pandemic response. There were constraints on sectoral funding, setbacks in specific policies, institutional weakening, and forms of resistance within the state and society. During the period studied, no radical changes were observed in the direction of the Brazilian health system, due to structural factors, the institutional density of the SUS, competing policy agendas, the interaction of coalitions of actors with varied interests, or even the period's short duration. However, fully understanding the impact of this critical juncture, which is still recent, requires assessing its medium- and long-term repercussions at the global, regional, and national levels.

Primary spontaneous pneumothorax is characterized by the accumulation of air within the pleural space in the absence underlying lung diseases. This study aims to evaluate the clinical characteristics, treatment modalities, and recurrence rates of child and adolescent patients diagnosed with primary spontaneous pneumothorax in our clinic.

Patients under the age of 18 diagnosed with primary spontaneous pneumothorax via chest X-ray and thoracic computed tomography were included in the study. Patients' age, gender, presenting complaints, side of pneumothorax, treatment method, complication status, history of recurrence, smoking status, body mass index, and Haller index were recorded. The pneumothorax ratio was calculated radiologically according to the British Thoracic Society guidelines and using the Kircher-Swartzel formula.

Total of 33 patients were included in the study. During follow-up, 15 recurrent episodes occurred, yielding a total of 48 pneumothorax episodes for analysis. No patient experienced more than two total episodes. A statistically significant relationship was identified between the pneumothorax percentage and the development of recurrence. No statistically significant difference was found between body mass/Haller/gender index and the development of recurrence. No significant association was found between the side of pneumothorax (left, right, or bilateral) and the development of either recurrence or complications.

Although management strategies similar to adult protocols are applied in childhood pneumothorax, individualized treatment planning based on patient characteristics is of paramount importance. Large-scale studies are required to establish a standardized treatment protocol.

The aim of this study was to evaluate prenatal characteristics, associated anomalies, and perinatal and postnatal outcomes of fetuses diagnosed with congenital pulmonary airway malformation at a tertiary referral center.

This retrospective study analyzed data from 56 fetuses diagnosed prenatally with congenital pulmonary airway malformation by ultrasonography between January 2015 and December 2024. Maternal age, gestational age at diagnosis and delivery, lesion localization and ultrasonographic type, congenital pulmonary airway malformation volume ratio, presence of hydrops fetalis and associated anomalies, karyotype results, perinatal losses, postnatal surgical requirement, and long-term outcomes were evaluated.

The median gestational age at diagnosis was 23 weeks (range: 15-32). Lesions were located in the right lung in 58.9% and in the left lung in 41.1% of cases. Mixed lesions were most common (44.6%), followed by microcystic (30.4%) and macrocystic (25.0%) types. Congenital pulmonary airway malformation volume ratio >1.6 was observed in 17.9% of cases, and hydrops fetalis developed in 12.5%. Associated structural anomalies were detected in 12.5% of fetuses. Pregnancy termination, intrauterine fetal demise, and neonatal death occurred in 7.1, 1.8, and 1.8% of cases, respectively. Spontaneous lesion regression was observed in 62.5% of cases, while only 12% of live-born infants required postnatal surgery. During a mean follow-up of 72.5 months (range: 22-96), no congenital pulmonary airway malformation-related mortality was observed.

Most fetuses with prenatal congenital pulmonary airway malformation diagnosis have favorable perinatal and long-term outcomes. High congenital pulmonary airway malformation volume ratio and hydrops fetalis are key predictors of adverse outcomes, whereas conservative management is safe and effective in asymptomatic cases.

This paper aiming at the formulation of a parsimonious two-parameter family of lifetime distributions obtained by a simple but flexible exponential-type transformation of an arbitrary baseline CDF (the Flexible Exponential-Type Family, FETF) and study in detail its Exponential-Type Weibull (ETW) special case. The ETW retains analytical tractability while permitting bathtub-shaped and unimodal hazard rate behavior frequently observed in epidemiology and reliability. To theoretically validate the model, we derive key distributional properties, including the probability density function, survival function, and hazard rate. We present maximum-likelihood estimation (MLE): score equations, observed Fisher information, and asymptotic confidence intervals. We address requirements that guarantee negative definiteness and provide explicit formulas for the Hessian (observed information). Monte Carlo simulations evaluating bias, mean squared error, and model selection frequency as well as application to COVID-19 data (n = 106) from Mexican public records are used to empirically validate the performance of the proposed ETW distribution. The ETW consistently performs better than well-known competing models, such as the Weibull and other state-of-the-art distributions, across information requirements and goodness-of-fit metrics. For simulating non-monotonic hazard issues in epidemiology and reliability investigations, the ETW distribution provides a flexible and computationally easy tool.

Accurately predicting optimal continuous positive airway pressure (CPAP) using traditional PSG parameters remains challenging. Respiratory endotypes derived from PSG can reflect the pathophysiological mechanisms of diseases to a certain extent and are expected to provide a novel perspective for individualized pressure prediction. 114 Chinese adults with obstructive sleep apnea (OSA) underwent two overnight in-laboratory PSG recordings. Optimal CPAP pressure was defined by standardized manual titration performed on the second night. The analysis incorporated three sets of variables: respiratory endotypes, anthropometric indicators, and PSG respiratory parameters. After initial correlation screening, significant variables were entered into a stepwise multiple linear regression model. The dataset was randomly split into training (80%) and validation (20%) sets to assess predictive performance. A total of 114 participants (15 mild, 38 moderate, 61 severe OSA) were included. The prediction model included loop gain (LG1), ventilation capacity (Vpassive, Vmin), BMI, apnea index (AI), mean respiratory event-related oxygen desaturation (RE-OD-Mean), longest apnea duration (Ap-Dur-Long), and respiratory-related arousal index (RR-ArI): CPAP = 0.708 + 1.804×LG1 + 0.023×Vpassive - 0.015×Vmin + 0.117×BMI + 0.003×AI - 0.074×RE-OD-Mean + 0.019×Ap-Dur-Long + 0.043×RR-ArI. The final model demonstrated acceptable predictive performance in the internal validation set (R² = 0.497; RMSE = 1.507 cmH₂O). Among the retained predictors, LG1 showed the largest effect size, with each 1-unit increase associated with an approximately 1.8 cmH₂O higher predicted CPAP pressure. Integrating respiratory endotypes with anthropometric indicators and PSG respiratory parameters provides a mechanism-based framework for CPAP pressure prediction. Collapsibility traits (Vpassive, Vmin) and ventilatory control stability (LG1) substantially enhance predictive accuracy, offering a more individualized approach to PAP therapy.

Influenza A and B viruses are considerable public health threats. Annual seasonal epidemics are driven by antigenic drift and cause an estimated 3-5 million severe cases and 290,000-650,000 deaths annually. The clinical presentation of seasonal influenza is typically an abrupt, uncomplicated acute respiratory illness with full recovery; however, it can lead to severe, life-threatening complications in individuals at high risk. Antigenic shift caused by reassortment of a seasonal influenza A virus with avian and/or swine influenza A viruses has led to unpredictable pandemics. The successful cross-species transmission of influenza A viruses requires key viral adaptations, including changes in receptor specificity and compatibility with host factors such as ANP32A. Host defence involves a layered innate response, which is antagonized by proteins, such as non-structural protein 1, and a robust adaptive immunity comprising cytotoxic CD8⁺ T cells targeting conserved internal proteins and B cells producing neutralizing antibodies. Diagnosis primarily depends on highly sensitive PCR-based methods and multiplexed rapid antigen tests. Prevention involves annually updated seasonal vaccines (including inactivated, live attenuated and protein-based vaccines), while treatment relies on early use of neuraminidase and polymerase acidic protein inhibitors. Research priorities include the development of improved vaccines and a better understanding of influenza virus transmission from animals to humans.

Large language models (LLMs) are increasingly applied in clinical decision support, yet their diagnostic performance in Chinese-language settings and under realistic clinical workflows remains unclear. In particular, how LLMs perform across diseases with different prevalence and under stepwise diagnostic processes has not been well characterized.

This study aimed to evaluate the diagnostic capabilities of LLMs for common diseases and rare diseases using clinical vignettes within a hypothetico-deductive framework and to identify their potential and limitations for clinical diagnosis.

We evaluated 4 Chinese LLMs (Doubao 1.5, DeepSeek-V3, Kimi K1.5, and Leftdoctor GPT 3.5) using 56 clinical cases (28 chronic obstructive pulmonary disease [COPD], and 28 relapsing polychondritis [RP]) sourced from the China Clinical Case Results Database (March 31-April 14, 2025). Patient information was provided incrementally, starting with the initial medical history, followed by physical examination, and laboratory results. Evaluation metrics included top-3 accuracy (RTop3D), top-1 accuracy (RTopD), final diagnostic accuracy (RFA), and mean reciprocal rank (MRR). Statistical analysis was performed using generalized estimating equations (GEE), Friedman tests, and Wilcoxon signed-rank tests with Bonferroni correction. In addition, a qualitative analysis was conducted to characterize recurrent patterns of diagnostic errors.

LLMs demonstrated significantly higher diagnostic accuracy for COPD compared to RP across all metrics (P<.001). Diagnostic accuracy improved after additional clinical information was provided, with the improvement mainly observed in RP cases. In RP, diagnostic accuracy increased from 32.14% to 71.43% for DeepSeek and from 35.71% to 78.57% for Doubao, whereas COPD accuracy remained consistently high across all diagnostic stages (82.14%-92.86%). For COPD, ranking performance was high and comparable among all models (MRR range: 0.82-0.89; P=.71). In RP, diagnostic performance differed significantly among models (MRR range: 0.10-0.39; P<.001). Qualitative analysis showed that COPD errors were mainly related to a failure to recognize specific features, whereas RP errors involved more diverse patterns, particularly the neglect of negative evidence and the failure to recognize specific features.

Chinese LLMs demonstrated relatively strong diagnostic performance for common diseases such as COPD, but lower and less stable performance for rare diseases such as RP. Additional clinical information improved diagnostic accuracy primarily in RP cases, although differences between models remained evident under diagnostically complex conditions. Error patterns in RP cases suggest that current LLMs remain limited in their ability to integrate complex clinical information and exclusionary findings. Careful evaluation and appropriate clinical oversight remain important for their application in clinical practice.

To describe the patterns of medication use among individuals with Covid-19 to treat the disease in Brazil, according to area of residence, demographic and socioeconomic characteristics, religion, and level of trust in scientists.

Epicovid 2.0 National Survey (2024) in 133 municipalities. The analysis included participants who reported having had an episode of Covid-19. The use of antibiotics, azithromycin, antipyretics, chloroquine, and ivermectin was assessed, in addition to the composite outcomes: use of chloroquine and/or ivermectin; chloroquine, ivermectin, and/or azithromycin (CIA); and use of any medication. The frequency of use and 95% confidence intervals were estimated, considering the complex sampling design and sample weighting.

The frequency of use of any medication to treat Covid-19 was 63.0% (95%CI 60.0-65.9). Antipyretics were the most commonly used (53.7%), followed by antibiotics (36.2%) and azithromycin (27.2%). The isolated use of ivermectin was reported by 23.6% and that of chloroquine by 12.1%; the use of ivermectin and/or chloroquine reached 27.8% and that of CIA, 39.0%. Overall, medication use was more frequent in the North, Northeast, and Central-West regions and among women. Use was concentrated among adults aged 40-59, people with low educational attainment, and those with lower incomes. Self-identified black and brown individuals reported higher use of chloroquine. Use of chloroquine, ivermectin, and combinations of these medications was more common among evangelicals (0.05 < p < 0.1) and among people who consulted doctors (p < 0.001). Participants who reported distrusting scientists reported higher use of chloroquine and chloroquine/ivermectin compared to those who reported trusting scientists.

Four out of ten people who reported episodes of Covid-19 consumed medications not recommended by science to treat the disease. Medication use tended to be more frequent among women, in the northern half of Brazil, among evangelicals, and among people with lower income and education levels. These groups should be prioritized in future campaigns on the appropriate use of medications.

A 28-year-old man with HIV (diagnosed eight years prior, last CD4 count 23 cells/mm3) and prior tuberculosis (cured, then confirmedly reinfected with treatment default) presented with cachexia, diarrhea, chest pain, and tachypnea with increased work of breathing that required orotracheal intubation. Admission chest CT showed extensive bilateral consolidations with air bronchograms, suggestive of previous mycobacterial infection and/or possible new bacterial infection. Initially managed as sepsis, blood cultures grew Rhodococcus equi (four samples). Molecular testing confirmed Mycobacterium tuberculosis in sputum and tracheal aspirate, establishing coinfection and exceeding the similarities in acid-fast staining, clinical, and radiological findings between the two organisms. Treatment included antituberculosis therapy associated with clarithromycin and vancomycin (14 days). The patient achieved complete clinical improvement with partial radiological resolution (residual cavitations). He was discharged after 25 days, but was lost to follow-up and died three months later from probable septic shock. This report highlights a rare M. tuberculosis/R. equi coinfection in an immunosuppressed patient, emphasizing diagnostic challenges and the importance of therapeutic adherence in advanced HIV.