Hydroxychloroquine safety, comparison between no Covid-19 and Covid-19 patients. Data from the Spanish Pharmacovigilance Database (preprint)

Aim: To compare the cases reported to the Spanish Pharmacovigilance System (SEFV-H) with HCQ used in COVID-19 vs. HCQ used in other indications. Methods. All cases of adverse drug reactions (ADR) submitted to the Spanish Pharmacovigilance database (FEDRA) from 1 January 1982 to 19 February 2021 suspected to be induced by HCQ were identified. Cases were classified into two groups: no-Covid patients and Covid patients. Frequencies of ADR were compared. Reporting Odds Ratios (ROR) with its lower limit of the 95% confidence interval (-ROR) and Omega (Ω) and its lower limit of the 95% credibility interval (Ω -025) were obtained to estimate disproportionalities. Results. More severe cases were reported with the use of HCQ in Covid. Main differences in frequency were observed in hepatobiliary, skin, gastrointestinal, eye, nervous system and heart ADRs. During the Covid-19 pandemic, disproportionality was found for Torsade de Pointes/QT prolongation with a ROR (-ROR) of 132.8 (76.7); severe hepatotoxicity, 18.7 (14.7); dyslipidaemias, 12.1 (6.1); shock, 9.5 (6.9) and ischaemic colitis, 8.9 (2.6). Myopathies, haemolytic disorders and suicidal behaviour increased their disproportionality during the pandemic. Disproportionality was observed for neoplasms, haematopoietic cytopaenias and interstitial lung disease in the pre-Covid period. Ω showed potential interactions between HCQ and azithromycin, ceftriaxone, lopinavir and tocilizumab . Conclusions. The use of HCQ in Covid-19 changed its safety profile. Of particular concern during the pandemic were arrhythmias, hepatotoxicity, severe skin reactions and suicide risk, but not ocular disorders. Some ADRs identified as signals would require more detailed analyses.

Comparison of chest radiological findings between coronavirus disease 2019 pneumonia and anti-melanoma differentiation-associated gene 5 antibody- positive interstitial pneumonia by artificial intelligence-based quantitative computed tomography image analysis (preprint)

Background Coronavirus disease 2019 (COVID-19) pneumonia and anti-melanoma differentiation-associated gene 5 antibody-positive interstitial pneumonia (MDA5-IP) share many similarities; however, the treatment and management of the two diseases are different. In the early stages of developing a treatment plan, it is crucial to distinguish between the two diseases. This study was conducted to compare the radiological findings between COVID-19 pneumonia and MDA5-IP.Methods We recruited patients with COVID-19 pneumonia between January and June 2020. The control group comprised patients with MDA5-IP admitted between April 2013 and December 2019. Patients with thin-slice computed tomography (CT) images within 2 days of admission were enrolled. The CT images were analyzed using an artificial intelligence-based quantitative CT software program. Radiological findings were classified as faint ground-glass opacity (GGO), GGO, reticulation, consolidation, honeycombing, nodules, hyperlucency, or interlobular septum. The volumes of these radiological findings were compared between the two groups. A classification and regression tree algorithm was used to develop a prediction model to stratify the risk of COVID-19 pneumonia.Results We enrolled 72 and 15 patients in the COVID-19 pneumonia and MDA5-IP group, respectively. Faint GGO and consolidations were observed more extensively in patients with MDA5-IP. The prediction model was developed at cut-off values of faint GGO, < 30%; GGO, ≥ 10%, and consolidation < 1%. This prediction model contributed to changing post-test probability in 26% of cases.Conclusion The COVID-19 group showed fewer faint GGO and consolidation volumes than the MDA5-IP group. We developed a predictive model to stratify the risk of COVID-19 pneumonia.

COVID-19 Caused by the Omicron Variant in Lung Transplant Recipients: A Single Center Case Series (preprint)

Background: Limited data from the Chinese experience are available regarding the infection status, clinical characteristics, treatments and early outcomes of lung transplant recipients (LTRs) afflicted with coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 Omicron Variant. Methods: We conducted a study on LTRs with COVID-19 caused by the Omicron Variant from November 17, 2022, to May 1, 2023. Clinical information was gathered through electronic medical records, questionnaires, or follow-up telephone calls. To identify potential risk factors for severe disease progression, a multivariate logistic analysis was performed. Results: 178 LTRs with COVID-19 were included, with 50% (89/178) requiring hospitalization for an average stay of 16 days (IQR: 9.5-25.5 days). The most common symptoms were fever (79.8%), dry cough (75.3%) and fatigue (61.8%). Ultimately, 17 recipients succumbed to COVID-19-related respiratory failure or secondary multiple organ dysfunction, resulting in an overall mortality rate of 9.6%. Of the 89 hospitalized patients, 41.6% (37/89) eventually progressed to severe or critical disease, forming the Severe/Critical Group (S/C group), while the remaining 58.4% (52/89) had mild to moderate disease (M/M group). In comparison to the M/M group, the S/C group had higher CRP (59.6 vs. 16.8 mg/L, P＜0.01), ESR (45.5 vs. 22.5mm/h, P＜0.01) and D-dimer (1.09 vs. 0.65 mg/L, P＜0.05), but lower CD3+ T lymphocytes (577 vs. 962 cells/ul, P＜0.01) and CD4+ T lymphocytes (217 vs. 427 cells/ul, P＜0.01). The S/C group had significantly higher rates of combined pulmonary bacterial infection (67.6% vs. 38.5%, P＜0.01) and pulmonary fungal infection (73.0% vs. 38.5%, P＜0.01) during the course of COVID-19, nearly double that of the M/M group. In a multivariate logistic analysis, elevated CRP (>41.8mg/L), combined pulmonary fungal infection, and interstitial lung disease(ILD) as primary disease emerged as high-risk factors for developing the severe disease phenotype following Omicron variant infection in LTRs, with respective OR values of 4.23 (95% CI: 1.68-11.23), 4.76 (95% CI: 1.59-15.64), and 5.13 (95% CI: 1.19-29.17). Conclusions: LTRs displayed an increased vulnerability to combined lung bacterial or fungal infections following Omicron infection. CRP> 41.8mg/L, ILD as primary disease, and combined pulmonary fungal infection are high-risk factors for developing severe disease.

A 50-gene high-risk profile predictive of COVID-19 and Idiopathic Pulmonary Fibrosis mortality originates from a molecular imbalance in monocyte and T-cell subsets that reverses in survivors with post-COVID-19 Interstitial Lung Disease (preprint)

Background: We aim to study the source of circulating immune cells expressing a 50-gene signature predictive of COVID-19 and IPF mortality. Methods: Whole blood and Peripheral Blood Mononuclear cells (PBMC) were obtained from 231 subjects with COVID-19, post-COVID-19-ILD, IPF and controls. We measured the 50-gene signature (nCounter, Nanostring), interleukin 6 (IL6), interferon gamma;-induced protein (IP10), secreted phosphoprotein 1 (SPP1) and transforming growth factor beta (TGF-beta) by Luminex. PCR was used to validate COVID-19 endotypes. For single-cell RNA sequencing (scRNA-seq) we used Chromium Controller (10X Genomics). For analysis we used the Scoring Algorithm of Molecular Subphenotypes (SAMS), Cell Ranger, Seurat, Propeller, Kaplan-Meier curves, CoxPH models, Two-way ANOVA, T-test, and Fisher exact. Results: We identified three genomic risk profiles based on the 50-gene signature, and a subset of seven genes, associated with low, intermediate, or high-risk of mortality in COVID-19 with significant differences in IL6, IP10, SPP1 and TGF{beta}-1. scRNA-seq identified Monocytic-Myeloid-Derived Suppressive cells (M-MDSCs) expressing CD14+HLA DRlowCD163+ and high levels of the 7-gene signature (7Gene-M-MDSC) in COVID-19. These cells were not observed in post-COVID-19-ILD or IPF. The 43-gene signature was mostly expressed in CD4 T and CD8 T cell subsets. Increased expression of the 43 gene signature was seen in T cell subsets from survivors with post-COVID-19-ILD. The expression of these genes remained low in IPF. Conclusion: A 50-gene, high-risk profile in COVID-19 is characterized by a genomic imbalance in monocyte and T-cell subsets that reverses in survivors with post-COVID-19 Interstitial Lung Disease.

Immunomodulators and risk for breakthrough infection after third COVID-19 mRNA vaccine among patients with rheumatoid arthritis: A cohort study (preprint)

Objectives: To investigate COVID-19 breakthrough infection after third mRNA vaccine dose among patients with RA by immunomodulator drug class, and we hypothesized that CD20 inhibitors (CD20i) would have higher risk for breakthrough COVID-19 vs. TNF inhibitors (TNFi). Methods: We performed a retrospective cohort study investigating breakthrough COVID-19 among RA patients at Mass General Brigham in Boston, MA, USA. Patients were followed from the date of 3rd vaccine dose until breakthrough COVID-19, death, or end of follow-up (18/Jan/2023). Covariates included demographics, lifestyle, comorbidities, and prior COVID-19. We used Cox proportional hazards models to estimate breakthrough COVID-19 risk by immunomodulator drug class. We used propensity score (PS) overlap-weighting to compare users of CD20i vs. TNFi. Results: We analyzed 5781 patients with RA that received 3 mRNA vaccine doses (78.8% female, mean age 64.2 years). During mean follow-up of 12.8 months, 1173 (20.2%) had breakthrough COVID_19. Use of CD20i (adjusted HR 1.74, 95%CI 1.30-2.33) and glucocorticoid monotherapy (adjusted HR 1.47, 95%CI 1.09-1.98) were each associated with breakthrough COVID-19 compared to TNFi use. In the PS overlap-weighted analysis, CD20i users also had higher breakthrough COVID-19 risk than TNFi users (HR 1.62, 95%CI 1.02-2.56). A sensitivity analysis excluding patients with cancer or interstitial lung disease yielded similar findings. Conclusions: We identified CD20i and glucocorticoid monotherapy as risk factors for breakthrough COVID-19 among patients with RA after a 3rd vaccine dose. This contemporary study highlights the real-world impact of blunted immune responses in these subgroups and the need for effective risk mitigation strategies.

Expansion of profibrotic monocyte-derived alveolar macrophages in patients with persistent respiratory symptoms and radiographic abnormalities after COVID-19 (preprint)

As many as 10-30% of the over 760 million survivors of COVID-19 develop persistent symptoms, of which respiratory symptoms are among the most common. To understand the cellular and molecular basis for respiratory PASC, we combined a machine learning-based analysis of lung computed tomography (CT) with flow cytometry, single-cell RNA-sequencing analysis of bronchoalveolar lavage fluid and nasal curettage samples, and alveolar cytokine profiling in a cohort of thirty-five patients with respiratory symptoms and radiographic abnormalities more than 90 days after infection with COVID-19. CT images from patients with PASC revealed abnormalities involving 73% of the lung, which improved on subsequent imaging. Interstitial abnormalities suggestive of fibrosis on CT were associated with the increased numbers of neutrophils and presence of profibrotic monocyte-derived alveolar macrophages in BAL fluid, reflecting unresolved epithelial injury. Persistent infection with SARS-CoV-2 was identified in six patients and secondary bacterial or viral infections in two others. These findings suggest that despite its heterogenous clinical presentations, respiratory PASC with radiographic abnormalities results from a common pathobiology characterized by the ongoing recruitment of neutrophils and profibrotic monocyte-derived alveolar macrophages driving lung fibrosis with implications for diagnosis and therapy.

Frequency of slight interstitial lung lesions in coronavirus disease 2019 autopsy cases - potential risk factor of severe pneumonia (preprint)

The aim of this study was to clarify subclinical hidden interstitial lung disease (ILD) as a risk factor of severe pneumonia associated with coronavirus disease 2019 (COVID-19). We carefully examined autopsied lungs and chest computed tomography scanning (CT) images from patients with COVID-19 for interstitial lesions and then analyzed their relationship with disease severity. Among the autopsy series, subclinical ILD was found in 13/27 cases (48%) in the COVID-19 group, and in contrast, 8/65 (12%) in the control autopsy group (p=0.0006; Fisher’s exact test). We reviewed CT images from the COVID-19 autopsy cases and verified that subclinical ILD was histologically detectable in the CT images. Then, we retrospectively examined CT images from another series of COVID-19 cases in the Yokohama, Japan area between February–August 2020 for interstitial lesions and analyzed the relationship to the severity of COVID-19 pneumonia. Interstitial lesion was more frequently found in the group with the moderate II/severe disease than in the moderate I/mild disease (severity was evaluated according to the COVID-19 severity classification system of the Ministry of Health, Labor, and Welfare [Japan]) (moderate II/severe, 11/15, 73.3% versus moderate I/mild, 108/245, 44.1%; Fisher exact test, p=0.0333). In conclusion, it was suggested that subclinical ILD could be an important risk factor for severe COVID-19 pneumonia. A benefit of these findings could be the development of a risk assessment system using high resolution CT images for fatal COVID-19 pneumonia.

Effects of COVID-19 infection in patients with autoimmune pulmonary alveolar proteinosis: a single-center study (preprint)

Background:Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare interstitial lung disease. COVID-19 is associated with worse prognosis in previous lung diseases patients. But the prognosis of aPAP patients after infection with COVID-19 is unclear. In December 2022, China experienced a large-scale outbreak of Omicron variant of the SARS-CoV-2. In this study, we aim to explore the clinical outcomes of aPAP patients infected with COVID-19. Results: A total of 39 aPAP patients were included in this study. 30.77% patients had a decrease in oxygen saturation after COVID-19 infection. We compared the two groups of patients with or without decreased oxygen saturation after COVID-19 infection and found that patients who had previous oxygen therapy (decreased oxygen saturation vs. non decreased oxygen saturation: 6/12 vs. 4/27, P = 0.043), with lower baseline arterial oxygen partial pressure (74.50 ± 13.61 mmHg vs. 86.49 ± 11.92 mmHg, P = 0.009), lower baseline DLCO/VA% [77.0 (74.3, 93.6) % vs. 89.5 (78.2, 97.4) %, P = 0.036], shorter baseline 6MWD [464 (406, 538) m vs. 532 (470, 575) m, P = 0.028], higher disease severity score (P = 0.017), were more likely to have decreased oxygen saturation after COVID-19 infection. Conclusion: aPAP patients with poor baseline respiration have a higher probability of hypoxia after COVID-19 infection, but fatal events were rare.

The Role of Pulmonary Surfactant Phospholipids in Fibrotic Lung Diseases.

Diffuse parenchymal lung diseases (DPLD) or Interstitial lung diseases (ILD) are a heterogeneous group of lung conditions with common characteristics that can progress to fibrosis. Within this group of pneumonias, idiopathic pulmonary fibrosis (IPF) is considered the most common. This disease has no known cause, is devastating and has no cure. Chronic lesion of alveolar type II (ATII) cells represents a key mechanism for the development of IPF. ATII cells are specialized in the biosynthesis and secretion of pulmonary surfactant (PS), a lipid-protein complex that reduces surface tension and minimizes breathing effort. Some differences in PS composition have been reported between patients with idiopathic pulmonary disease and healthy individuals, especially regarding some specific proteins in the PS; however, few reports have been conducted on the lipid components. This review focuses on the mechanisms by which phospholipids (PLs) could be involved in the development of the fibroproliferative response.

Anti-synthetase syndrome masquerading as recurrent pneumonia.

Anti-synthetase syndrome (ASS) is a rare inflammatory myopathy with a wide variety of clinical presentations. ASS-related interstitial lung disease (ASS-ILD) presents with rapid onset and progression, which could often be confused with other more common acute processes such as pneumonia, especially when ILD can be the sole manifestation. A woman in her 50s presented with recurrent dyspnoea for 2 months requiring multiple hospital admissions, and each time, she was diagnosed with multifocal pneumonia and treated with antibiotics. On admission, the evaluation revealed a markedly elevated creatine kinase level at 3258 U/L and a CT scan of the chest revealed worsening scattered ground-glass opacities. Given the concern for ILD as the cause of antibiotic failure, she underwent bronchoscopy with bronchoalveolar lavage which revealed non-specific interstitial pneumonia. A subsequent myositis panel revealed a positive anti-Jo-1 antibody, and she was diagnosed with ASS-ILD. She completed a course of intravenous immunoglobulin and methylprednisolone and experienced significant clinical improvement with the resolution of hypoxaemia and improved polyarthralgia.ASS could often be misdiagnosed as other more common acute lung processes, as a clinically subtle course can escape detection given its rarity, as well as its non-specific and highly variable presentations. This case highlights the importance of early suspicion and consideration of performing specific autoantibody testing when evaluating patients with a suspicion of undifferentiated autoimmune condition.

Clinical and Immunological Characteristics of Prolonged SARS-CoV-2 Omicron Infection in Hematologic Disease (preprint)

Prolonged viral shedding (PVS) occurs when severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is not adequately cleared and has been associated with poor outcomes. However, it remains unclear whether the immunological and clinical characteristics of Omicron PVS in hematologic disease (HD) are identical to those of earlier variants. We retrospectively analyzed 160 patients with HD with Omicron breakthrough infections. Although the hospitalization rate was high (21.3 %), deaths attributable to COVID-19 occurred in only 2.5% of the cases. PVS developed in 36.9% of the evaluable patients. Factors such as B- and CD4+ T-cell depletion, recent use of anti-CD20 antibodies and bendamustine were found to be significant predictors of PVS. Analysis of T cell phenotypes showed an increase in exhausted CD4+ T cells in PVS, but not in CD8+ cells.  Neutralizing activities against recombinant spike proteins for three Omicron subvariants were significantly reduced. Notably, despite the high frequency of PVS, many patients previously treated with anti-CD20 antibodies and bendamustine ultimately recovered. Late-onset interstitial pneumonia is a fatal complication that can occur regardless of viral clearance. Despite the use of high-dose corticosteroids and potent antivirals, the optimal treatment for PVS remains unclear and should be individualized until a more effective strategy is established.

The fatal trajectory of pulmonary COVID-19 is driven by lobular ischemia and fibrotic remodelling.

BACKGROUND: COVID-19 is characterized by a heterogeneous clinical presentation, ranging from mild symptoms to severe courses of disease. 9-20% of hospitalized patients with severe lung disease die from COVID-19 and a substantial number of survivors develop long-COVID. Our objective was to provide comprehensive insights into the pathophysiology of severe COVID-19 and to identify liquid biomarkers for disease severity and therapy response. METHODS: We studied a total of 85 lungs (n = 31 COVID autopsy samples; n = 7 influenza A autopsy samples; n = 18 interstitial lung disease explants; n = 24 healthy controls) using the highest resolution Synchrotron radiation-based hierarchical phase-contrast tomography, scanning electron microscopy of microvascular corrosion casts, immunohistochemistry, matrix-assisted laser desorption ionization mass spectrometry imaging, and analysis of mRNA expression and biological pathways. Plasma samples from all disease groups were used for liquid biomarker determination using ELISA. The anatomic/molecular data were analyzed as a function of patients' hospitalization time. FINDINGS: The observed patchy/mosaic appearance of COVID-19 in conventional lung imaging resulted from microvascular occlusion and secondary lobular ischemia. The length of hospitalization was associated with increased intussusceptive angiogenesis. This was associated with enhanced angiogenic, and fibrotic gene expression demonstrated by molecular profiling and metabolomic analysis. Increased plasma fibrosis markers correlated with their pulmonary tissue transcript levels and predicted disease severity. Plasma analysis confirmed distinct fibrosis biomarkers (TSP2, GDF15, IGFBP7, Pro-C3) that predicted the fatal trajectory in COVID-19. INTERPRETATION: Pulmonary severe COVID-19 is a consequence of secondary lobular microischemia and fibrotic remodelling, resulting in a distinctive form of fibrotic interstitial lung disease that contributes to long-COVID. FUNDING: This project was made possible by a number of funders. The full list can be found within the Declaration of interests / Acknowledgements section at the end of the manuscript.

Role of GM-CSF in lung balance and disease.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor originally identified as a stimulus that induces the differentiation of bone marrow progenitor cells into granulocytes and macrophages. GM-CSF is now considered to be a multi-origin and pleiotropic cytokine. GM-CSF receptor signals activate JAK2 and induce nuclear signals through the JAK-STAT, MAPK, PI3K, and other pathways. In addition to promoting the metabolism of pulmonary surfactant and the maturation and differentiation of alveolar macrophages, GM-CSF plays a key role in interstitial lung disease, allergic lung disease, alcoholic lung disease, and pulmonary bacterial, fungal, and viral infections. This article reviews the latest knowledge on the relationship between GM-CSF and lung balance and lung disease, and indicates that there is much more to GM-CSF than its name suggests.

Contemporary Concise Review 2022: Interstitial lung disease.

Novel genetic associations for idiopathic pulmonary fibrosis (IPF) risk have been identified. Common genetic variants associated with IPF are also associated with chronic hypersensitivity pneumonitis. The characterization of underlying mechanisms, such as pathways involved in myofibroblast differentiation, may reveal targets for future treatments. Newly identified circulating biomarkers are associated with disease progression and mortality. Deep learning and machine learning may increase accuracy in the interpretation of CT scans. Novel treatments have shown benefit in phase 2 clinical trials. Hospitalization with COVID-19 is associated with residual lung abnormalities in a substantial number of patients. Inequalities exist in delivering and accessing interstitial lung disease specialist care.

Experience of severe and critical COVID-19 in interstitial lung disease patients (preprint)

Background Since the first case of severe COVID-19, its effect on patients with previous interstitial lung disease (ILD) has been uncertain. We aimed to describe baseline clinical characteristics in ILD patients hospitalized by several or critical COVID and compare mortality during hospitalization.Methods We studied patients with ILD plus COVID-19 and a control group, matched by age, 1:2 ratio of patients with COVID-19 without chronic lung disease. On admission, laboratory tests and sociodemographic variables we evaluated. We classified patients as severe or critically ill and compared baseline characteristics and mortality in each group. Additionally, we performed a sub-analysis of patients who died versus survivors.Results 41 patients and 82 controls were analyzed. We found differences in the ILD group, women 65 versus 33% (p < 0.001); lower leukocytes (9 ± 6 versus 11 ± 7, p = 0.01), lower neutrophils (8 ± 5 vs 10 ± 6, p = 0.02). Also, higher mortality in the ILD plus critical COVID-19 group (63 vs. 33%, p = 0.007). Patients who died had higher BMI (28 ± 6 vs. 25 ± 4kg/m2, p = 0.05), less extended hospital stay (20 ± 17 vs. 36 ± 27 days, p = 0.01), and less days of evolution (9 ± 7 vs. 16 ± 16, p = 0.05).Conclusions We found higher mortality in patients with ILD plus critical COVID-19. Higher BMI and comorbidities were present in the non-survivors. The most common presented ILD was secondary to autoimmune diseases.

[Follow-up of patients after COVID-19 pneumonia. Pulmonary sequelae]. / Seguimiento de los pacientes después de neumonía por COVID-19. Secuelas pulmonares.

Coronavirus disease 2019 (COVID-19) is an infection caused by SARS-CoV-2 that has caused an unprecedented pandemic with a high rate of morbidity and mortality worldwide. Although most cases are mild, there are a considerable number of patients who develop pneumonia or even acute respiratory distress syndrome (ARDS). After having recovered from the initial disease, many patients continue with various symptoms (fatigue, dry cough, fever, dyspnea, anosmia, and chest pain, among others.), which has led to consider the possible existence of "post-COVID-19 syndrome". Although the definition and validity of this syndrome are not clear yet, several studies report that individuals who have recovered from COVID-19 may have persistent symptoms, radiological abnormalities, and compromised respiratory function. Current evidence suggests that there is a large number of pulmonary sequelae after COVID-19 pneumonia (interstitial thickening, ground glass opacities, crazy paving pattern, and bronchiectasis, among others.). Likewise, it seems that pulmonary function tests (spirometry, DLCO, 6MWT, and measurement of maximum respiratory pressures), in addition to high-resolution computed axial tomographies (CAT scan), are useful for the assessment of these post-COVID-19 pulmonary sequelae. This review aims to describe the possible pulmonary sequelae after COVID-19 pneumonia, as well as to suggest diagnostic procedures for their correct assessment and follow-up; thus, allowing proper management by a multidisciplinary medical team.

COVID-19 es la enfermedad causada por el virus SARS-CoV-2, la cual ha ocasionado una pandemia sin precedentes, con gran cantidad de infectados y muertos en el mundo. Aunque la mayoría de los casos son leves, existe una cantidad considerable de pacientes que desarrollan neumonía o, incluso, síndrome de distrés respiratorio agudo (SDRA). Luego de recuperarse del cuadro inicial, muchos pacientes continúan con diversos síntomas (fatiga, tos seca, fiebre, disnea, anosmia, dolor torácico, entre otras), lo que ha llevado a considerar la posible existencia del "síndrome pos-COVID-19". Aunque la definición y validez de este síndrome aún no son claras, varios estudios reportan que los individuos recuperados de la COVID-19 pueden tener persistencia de síntomas, anormalidades radiológicas y compromiso en la función respiratoria. La evidencia actual sugiere que existe gran cantidad de secuelas pulmonares despues de una neumonía por COVID-19 (engrosamiento intersticial, infiltrado en vidrio esmerilado, patrón en empedrado, bronquiectasias, entre otras.). De igual forma, parece ser que las pruebas de función pulmonar (espirometría, prueba de difusión pulmonar de monóxido de carbono, prueba de caminata de seis minutos y la medición de las presiones respiratorias máximas), además de la tomografía axial computarizada de alta resolución, son útiles para evaluar las secuelas pulmonares pos-COVID-19. En esta revisión se pretende describir las posibles secuelas a nivel pulmonar posteriores a neumonía por COVID-19, así como sugerir procedimientos diagnósticos para su correcta evaluación y seguimiento, que permitan el manejo adecuado por parte de un equipo médico multidisciplinario.