Plaque Reduction Neutralization Test (PRNT) Accuracy in Evaluating Humoral Immune Response to SARS-CoV-2.

Massive vaccination positively impacted the SARS-CoV-2 pandemic, being a strategy to increase the titers of neutralizing antibodies (NAbs) in the population. Assessing NAb levels and understanding the kinetics of NAb responses is critical for evaluating immune protection. In this study, we optimized and validated a PRNT50 assay to assess 50% virus neutralization and evaluated its accuracy to measure NAbs to the original strain or variant of SARS-CoV-2. The optimal settings were selected, such as the cell (2 × 105 cells/well) and CMC (1.5%) concentrations and the viral input (~60 PFU/well) for PRNT-SARS-CoV-2 with cut-off point = 1.64 log5 based on the ROC curve (AUC = 0.999). The validated PRNT-SARS-CoV-2 assay presented high accuracy with an intraassay precision of 100% for testing samples with different NAb levels (low, medium, and high titers). The method displays high selectivity without cross-reactivity with dengue (DENV), measles (MV), zika (ZIKV), and yellow fever (YFV) viruses. In addition, the standardized PRNT-SARS-CoV-2 assay presented robustness when submitted to controlled variations. The validated PRNT assay was employed to test over 1000 specimens from subjects with positive or negative diagnoses for SARS-CoV-2 infection. Patients with severe COVID-19 exhibited higher levels of NAbs than those presenting mild symptoms for both the Wuhan strain and Omicron. In conclusion, this study provides a detailed description of an optimized and validated PRNT50 assay to monitor immune protection and to subsidize surveillance policies applied to epidemiologic studies of COVID-19.

Pulmonary function and exercise capacity six months after hospital discharge of patients with severe COVID-19.

INTRODUCTION: The long-term consequences of COVID-19, especially pulmonary impairment, are frequent but not well understood. The knowledge about sequels or long COVID-19 are necessary, considering the high prevalence and need for specific public strategies. METHOD: The study was conducted to evaluate symptoms (standardized questionnaire), pulmonary function (spirometry), and exercise capacity (6-minute-walk-test) at 30 (D30), 90 (D90), and 180 (D180) days after hospital discharge of patients surviving to severe COVID-19. We excluded in this follow up patients with comorbidities before COVID infection. RESULTS: 44 patients were included and 31 (26 men) completed the 6-month follow-up (age mean 53.6 ± 9.6 years). At D180, 28% presented still at least one symptom. The most common was dyspnea (17.2%), followed by cough (13.8%), and myalgia (10.3%). All spirometric parameters showed progressive improvement from D30 to D180. However, 16% maintained a restrictive pattern on spirometry test, 44% presented desaturation on the 6-minute walk-test, and 25% walked < 75% of the predicted value. CONCLUSION: 6-months after hospital discharge, reduced pulmonary function and reduced exercise capacity was founded frequently and more than a quarter remained symptomatic. The persistent symptoms and functional impairment suggest that sequels and development of Long COVID-19 are very common. The identification of these patients to provide the necessary health care is a challenging task, considering the large number of patients infected and surviving to COVID-19 disease.

Clinical risk factors for predicting anti-Sars-Cov-2 antibody immunoreactivity duration after mild COVID-19 infection / Fatores de risco clínicos para predizer a duração da imunoresatividade do anticorpo anti-Sars-Cov-2 após infecção leve por COVID-19

Introduction: coronavirus disease 2019 (COVID-19) is a complex multisystem disorder. It is not yet well known whether symptoms in the acute phase correlate with the duration of the immune response and the persistence of chronic symptoms.Objective: this study aimed to assess and monitor the clinical symptoms of COVID-19 and correlate them with the production of neutralizing antibodies.Methods: a cohort of 69 health workers at the University Hospital of the Federal University of Espírito Santo (HUCAM-UFES/EBSERH) diagnosed with SARS-CoV-2 infection confirmed via RT-PCR (Real-Time Reverse Transcription­Polymerase Chain Reaction) were evaluated from the onset of symptoms up to six months. SARS-CoV-2 IgG and IgM assays were used to detect the presence of IgG and IgM against the nucleocapsid protein of SARS-CoV-2 in serum samples. IgG and IgM antibody serology, pulmonary function via spirometry, and the clinical evolution of patients were performed at 15, 30, 45, 60, 90, and 180 days after the onset of COVID-19 symptoms.Results: sixty-nine health workers (age, 40 ± 10 years; 74% women) were evaluated for six months. All subjects showed mild to moderate COVID-19. The mean number of symptoms was 5.1 (± 2.3). The most common initial symptoms were muscle pain (77%), headache (75%), anosmia (70%), ageusia (64%), runny nose (59%), fever (52%), and coughing (52%). After 30 days, the patients had anosmia (18%), asthenia (18%), adynamia (14%), muscle pain (7%), and ageusia (7%). Regarding lung function, 9.25% presented with an obstructive pattern, and all recovered after six months. Of all analyzed participants, 18/69 (26%) did not have any reactive IgG or IgM values in any of the assessments. The IgG serology curve showed a peak, whereas IgM had the highest mean value on the 15th day. There was a progressive decrease and levels similar to those at baseline after 90 days, and 15/53 (28%) remained with reactive IgG after six months. Sore throat and shortness of breath were found to be independent risk factors, and patients with these symptoms were 5.9 times more likely to have reactive IgG on the 180th day. Patients with diarrhea were four times more likely to have reactive IgM.Conclusion: our findings showed that 26% of patients did not produce a humoral response post-mild COVID-19. Their antibody titers dropped significantly after 90 days, and only 28% maintained reactive IgG antibodies after six months. Sore throat and shortness of breath are predictors of a longer duration of the humoral immune response.

Introdução: a doença causada pelo coronavírus (COVID-19) é complexa e multissistêmica. Ainda não se sabe se os sintomas da fase aguda estão correlacionados com a duração da resposta imune e com a persistência dos sintomas crônicos.Objetivo: o presente estudo visa acessar e monitorar os sintomas clínicos do COVID-19, correlacionando-os com a produção de anticorpos neutralizantes.Método: uma coorte de 69 profissionais da saúde da Universidade Federal do Espírito Santo (HUCAM-UFES/EBSERH) diagnosticados com infecção por SARS-CoV-2 confirmada via RT-PCR (Real-Time Reverse Transcription-Polymerase Chain Reaction) foram avaliados do início dos sintomas até seis meses depois. Exames laboratoriais de IgG e IgM foram utilizados para detectar a presença de IgG e IgM contra a proteína do nucleocapsídeo do vírus SARS-CoV-2 nas amostras de plasma sanguíneo. Sorologia de anticorpos IgG e IgM, função pulmonar via espirometria e avaliação clínica dos pacientes foram realizadas nos dias 15, 30, 45, 60, 90 e 180 após o início dos sintomas da doença.Resultados: sessenta e nove profissionais da saúde (idade, 40 ± 10 anos; 74% mulheres) foram avaliados por seis meses. Todos apresentaram a forma leve a moderada do COVID-19. O número médio de sintomas foi 5.1 (± 2.3). O sintoma inicial mais comum foi dor muscular (77%), cefaleia (75%), anosmia (70%), ageusia (64%), coriza (59%), febre (52%), e tosse (52%). Após 30 dias, os pacientes mantiveram anosmia (18%), astenia (18%), adinamia (14%), dor muscular (7%), e ageusia (7%). Em relação à função pulmonar, 9.25% apresentaram padrão obstrutivo e todos recuperaram ao final dos seis meses. Dentre todos os participantes analisados, 18/69 (26%) não obtiveram nenhum valor de IgG e IgM considerados reagentes nos exames realizados. A curva sorológica de IgG mostrou um pico enquanto a de IgM apresentou seu maior valor médio no 15º dia. Houve um declínio progressivo e níveis similares aos basais aos 90. 15/53 (28%) permaneceram com IgG reagente após seis meses. Dor de garganta e dispneia foram considerados fatores de risco independentes, e os pacientes com esses sintomas tiveram 5,9 vezes mais chances de apresentar IgG reativa no 180º dia. Pacientes com diarreia tiveram quatro vezes mais chances de apresentar IgM reagente.Conclusão: nossos achados mostraram que 26% dos pacientes não produziram uma resposta humoral pós-COVID-19 leve. Seus títulos de anticorpos caíram significativamente após 90 dias e apenas 28% mantiveram anticorpos IgG reativos após seis meses. Dor de garganta e dispneia foram preditores de maior duração da resposta imune humoral

Pulmonary function and exercise capacity six months after hospital discharge of patients with severe COVID-19

ABSTRACT Introduction: The long-term consequences of COVID-19, especially pulmonary impairment, are frequent but not well understood. The knowledge about sequels or long COVID-19 are necessary, considering the high prevalence and need for specific public strategies. Method: The study was conducted to evaluate symptoms (standardized questionnaire), pulmonary function (spirometry), and exercise capacity (6-minute-walk-test) at 30 (D30), 90 (D90), and 180 (D180) days after hospital discharge of patients surviving to severe COVID-19. We excluded in this follow up patients with comorbidities before COVID infection. Results: 44 patients were included and 31 (26 men) completed the 6-month follow-up (age mean 53.6 ± 9.6 years). At D180, 28% presented still at least one symptom. The most common was dyspnea (17.2%), followed by cough (13.8%), and myalgia (10.3%). All spirometric parameters showed progressive improvement from D30 to D180. However, 16% maintained a restrictive pattern on spirometry test, 44% presented desaturation on the 6-minute walk-test, and 25% walked < 75% of the predicted value. Conclusion: 6-months after hospital discharge, reduced pulmonary function and reduced exercise capacity was founded frequently and more than a quarter remained symptomatic. The persistent symptoms and functional impairment suggest that sequels and development of Long COVID-19 are very common. The identification of these patients to provide the necessary health care is a challenging task, considering the large number of patients infected and surviving to COVID-19 disease.

Anti-SARS-CoV-2 antibody immunoreactivity profiles during COVID-19 recurrence.

BACKGROUND: This study aimed to evaluate IgG and IgM levels in COVID-19 recurrence. METHODS: The serum antibody levels and clinical data from 73 healthcare workers with SARS-CoV-2 divided into seroconverted (n=51) and non-seroconverted (n=22) groups were assessed. The presence of specific anti-nucleocapsid (anti-N) IgM and IgG for SARS-CoV-2 was evaluated. IgG antibodies to the SARS-CoV-2 spike receptor-binding domain were used to confirm non-seroconversion in all negative anti-N. RESULTS: Four recurrent cases displayed mild symptoms and were non-seroconverted until the recurrence of symptoms. CONCLUSIONS: Undetectable anti-nucleocapsid IgM and IgG levels may be correlated with symptomatic COVID-19 recurrence.

Anti-SARS-CoV-2 antibody immunoreactivity profiles during COVID-19 recurrence

ABSTRACT Background: This study aimed to evaluate IgG and IgM levels in COVID-19 recurrence. Methods: The serum antibody levels and clinical data from 73 healthcare workers with SARS-CoV-2 divided into seroconverted (n=51) and non-seroconverted (n=22) groups were assessed. The presence of specific anti-nucleocapsid (anti-N) IgM and IgG for SARS-CoV-2 was evaluated. IgG antibodies to the SARS-CoV-2 spike receptor-binding domain were used to confirm non-seroconversion in all negative anti-N. Results: Four recurrent cases displayed mild symptoms and were non-seroconverted until the recurrence of symptoms. Conclusions: Undetectable anti-nucleocapsid IgM and IgG levels may be correlated with symptomatic COVID-19 recurrence.

Pulmonary function evaluation after hospital discharge of patients with severe COVID-19.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) may be associated with prolonged symptoms and post-recovery health impairment. This study aimed to evaluate the persistence of symptoms, lung function, and pulmonary diffusion for carbon monoxide (DLCO) in patients between 15 and 30 days after hospital discharge after admission for severe COVID-19. METHODS: The evaluation consisted of 1) comparative analysis between the initial symptoms and symptoms still present at the post-discharge evaluation 2) analysis of the chest images obtained during hospitalization, and 3) conducting spirometry, plethysmography, and DLCO assessment. RESULTS: Forty-one patients who were hospitalized for 16±8 days with severe COVID-19 were included. Patients were predominantly men (73%) and had a mean age of 51±14 years. The most frequent comorbidities were arterial hypertension (51%) and diabetes mellitus (37%). Pulmonary evaluation was performed a mean of 36 days after the onset of symptoms, with the most frequent persistent symptoms being dyspnea (83%) and coughing (54%). Approximately 93% of patients still had at least one symptom, and 20% had more than five symptoms. Chest imaging revealed a typical pattern of COVID-19 on X-ray (93%) and computer tomography (95%). Lung function test results showed a restrictive pattern with a reduction in forced vital capacity (FVC) in 54% of individuals, with an average FVC of 78±14%. A reduction in DLCO was observed in 79% of patients. CONCLUSIONS: We observed a high prevalence of symptoms, in addition to a significant change in lung function and DLCO, in the post-discharge assessment of patients requiring hospitalization after admission for COVID-19.

Pulmonary function evaluation after hospital discharge of patients with severe COVID-19

OBJECTIVES: Coronavirus disease 2019 (COVID-19) may be associated with prolonged symptoms and post-recovery health impairment. This study aimed to evaluate the persistence of symptoms, lung function, and pulmonary diffusion for carbon monoxide (DLCO) in patients between 15 and 30 days after hospital discharge after admission for severe COVID-19. METHODS: The evaluation consisted of 1) comparative analysis between the initial symptoms and symptoms still present at the post-discharge evaluation 2) analysis of the chest images obtained during hospitalization, and 3) conducting spirometry, plethysmography, and DLCO assessment. RESULTS: Forty-one patients who were hospitalized for 16±8 days with severe COVID-19 were included. Patients were predominantly men (73%) and had a mean age of 51±14 years. The most frequent comorbidities were arterial hypertension (51%) and diabetes mellitus (37%). Pulmonary evaluation was performed a mean of 36 days after the onset of symptoms, with the most frequent persistent symptoms being dyspnea (83%) and coughing (54%). Approximately 93% of patients still had at least one symptom, and 20% had more than five symptoms. Chest imaging revealed a typical pattern of COVID-19 on X-ray (93%) and computer tomography (95%). Lung function test results showed a restrictive pattern with a reduction in forced vital capacity (FVC) in 54% of individuals, with an average FVC of 78±14%. A reduction in DLCO was observed in 79% of patients. CONCLUSIONS: We observed a high prevalence of symptoms, in addition to a significant change in lung function and DLCO, in the post-discharge assessment of patients requiring hospitalization after admission for COVID-19.

The use of portable monitoring for sleep apnea diagnosis in adults.

Due to increasing demand for sleep services, there has been growing interest in ambulatory models of care for patients with obstructive sleep apnea (OSA). The implementation of alternative approaches to the current management by full polysomnography (PSG) in the sleep laboratory is necessary for diagnosing this syndrome due to the high cost of full-night PSG. A good alternative option for OSA diagnosis is portable monitoring (PM), which is known for its accuracy, ease of management and lower cost when compared with full PSG. PM has not been well validated for OSA diagnosis in patients with medical comorbidities or in elderly individuals and children. PM may be recommended as an alternative method to PSG for patients with high clinical risk for OSA. In the present review, we describe the use of PM for OSA diagnosis and evaluate the current progress, costs, limitations and applications of these devices in various groups of patients, particularly for patients with comorbid diseases.

Is portable monitoring for diagnosing obstructive sleep apnea syndrome suitable in elderly population?

PURPOSE: Obstructive sleep apnea syndrome (OSAS) is highly prevalent in the elderly. Unattended, at-home portable monitoring (PM) is a diagnostic alternative to polysomnography in adults with high clinical probability of OSAS. However, no studies have evaluated the diagnostic accuracy of PM in elderly population. The aim of our study was to evaluate the effectiveness of PM in elderly patients. METHODS: We selected patients aged over 65 years with suspected OSAS. Two-order randomized evaluations were performed: one night of at-home PM (PMhome) and one night of simultaneous PM and polysomnography (PSG) in the sleep lab (PSG+PM). We obtained three different apnea-hypopnea index (AHI): AHI from PSG (AHI PSG), AHI from at-home PM (AHI PMhome), and AHI from PM+PSG (AHI PM+PSG). Two technicians, blinded to the recording order, scored each sleep study. RESULTS: We studied a total of 43 patients. No difference between the AHI values for each of the different recordings was found (p > 0.05). There was good correlation between AHI PSG and AHI PMhome (r = 0.67) and AHI PSG+PM (r = 0.84). The area under the receiver operator curve was above 0.83, indicating good sensitivity and a positive predictive value for AHI with cutoffs of 5, 15, and 30 and good specificity and negative predictive value for AHI values above 15. Correlation, accuracy, and agreement were greater when the recordings were made simultaneously. CONCLUSIONS: PM was effective for diagnosing OSAS in the elderly and can be used as an alternative to PSG in elderly patients with a high clinical probability of OSAS.

Portable monitoring devices in the diagnosis of obstructive sleep apnea: current status, advantages, and limitations.

Recent years have seen a growing interest in the use of portable monitoring devices for the diagnosis of obstructive sleep apnea syndrome. These have the potential to be used in lieu of the more complicated and uncomfortable alternative, polysomnography, which has long been considered to be the gold standard for the diagnosis of this relatively prevalent condition. Following their approval in 2008 by the Center of Medicare and Medicaid Services, the federal agency which administers Medicare and Medicaid in the United States, there has been extensive discussion about the utility and validity of these devices for use in the diagnosis of obstructive sleep apnea syndrome. Although there are various models of portable monitoring devices, the literature contains little information regarding how each device should be used in specific age groups, patients presenting comorbidities, and asymptomatic patients. Additionally, studies about the cost-effectiveness of this diagnostic method are scarce and conflicting. Therefore, this objective of this study was to review what has been learned about portable monitoring devices over time, as well as to examine the recent progress, advantages, limitations, and applications of these devices in the diagnosis of obstructive sleep apnea syndrome in different groups of patients.

Monitorização portátil no diagnóstico da apneia obstrutiva do sono: situação atual, vantagens e limitações / Portable monitoring devices in the diagnosis of obstructive sleep apnea: current status, advantages, and limitations

Nos últimos anos, é crescente o interesse pela utilização de aparelhos de monitoramento portáteis para o diagnóstico da síndrome da apneia obstrutiva do sono, como uma alternativa mais simples e confortável à polissonografia, que é o exame considerado o padrão ouro para o diagnóstico dessa condição relativamente prevalente. A liberação do uso desses equipamentos pelo Center of Medicare and Medicaid Services, agência federal que administra os serviços médicos nos Estados Unidos da América, em 2008, resultou em ampla discussão sobre a utilidade e validade desses equipamentos para o diagnóstico de síndrome da apneia obstrutiva do sono. Apesar de haver vários modelos de equipamentos de monitorização portátil, há pouca informação na literatura a respeito de como cada equipamento deveria ser utilizado em grupos etários específicos, portadores de comorbidades e pacientes assintomáticos. Além disso, estudos de custo-efetividade desse método diagnóstico são escassos e conflitantes. Portanto, o objetivo do presente estudo foi revisar a evolução dos conhecimentos no uso de equipamentos de monitorização portátil, bem como examinar os avanços recentes, vantagens, limitações e aplicações desses equipamentos para o diagnóstico de apneia obstrutiva do sono em diferentes grupos de pacientes.

Recent years have seen a growing interest in the use of portable monitoring devices for the diagnosis of obstructive sleep apnea syndrome. These have the potential to be used in lieu of the more complicated and uncomfortable alternative, polysomnography, which has long been considered to be the gold standard for the diagnosis of this relatively prevalent condition. Following their approval in 2008 by the Center of Medicare and Medicaid Services, the federal agency which administers Medicare and Medicaid in the United States, there has been extensive discussion about the utility and validity of these devices for use in the diagnosis of obstructive sleep apnea syndrome. Although there are various models of portable monitoring devices, the literature contains little information regarding how each device should be used in specific age groups, patients presenting comorbidities, and asymptomatic patients. Additionally, studies about the cost-effectiveness of this diagnostic method are scarce and conflicting. Therefore, this objective of this study was to review what has been learned about portable monitoring devices over time, as well as to examine the recent progress, advantages, limitations, and applications of these devices in the diagnosis of obstructive sleep apnea syndrome in different groups of patients.