ABSTRACT
Background. Breakthrough infections post-COVID-19 vaccination increase with waning immunity and typically produce milder disease than infections in unvaccinated individuals. We investigated immuno-virologic responses and COVID-19 symptom burden upon breakthrough infection in participants from a Phase 3 study of 2-dose primary series AZD1222 vaccination (NCT04516746) to explore disease attenuation. Methods. Study participants who experienced protocol-defined COVID-19 symptoms initiated a series of illness visits over 28 days with collection of sera, nasopharyngeal (NP) swabs and saliva samples (SS), and documentation of symptoms (data-cut off: July 30, 2021). For baseline-seronegative participants with PCR-confirmed SARS-CoV-2 infection >=15 days after dose 2 of AZD1222 or placebo we assessed: anti-SARS-CoV-2 spike (S), nucleocapsid (N) and neutralizing antibody (Ab) titers by multiplex immunoassay and SARS-CoV-2 pseudovirus assay in sera;viral load by quantitative RT-PCR in NP swabs;and viral shedding by qualitative and quantitative RT-PCR in SS. Data were stratified by age and SARS-CoV-2 variant, and time since primary series dose 2. Results. Illness Day 1 (ILL-D1) S Ab GMTs in AZD1222 vaccinees were similar to peak GMTs seen 14 days after dose 2 of AZD1222 and were higher vs placebo at all timepoints. The magnitude of S Ab response differed by age: median GMTs were lower at ILL-D1 and higher at ILL-D14 in vaccinees aged >=65 vs 18-64 years (Fig.1). ILL-D1 overall, SARS-CoV-2 ancestral, alpha, and epsilon variant viral load titers in NP swabs were lower in vaccinees vs placebo (Fig 2). Mean viral load in NP swabs and viral shedding titers in SS were lower in vaccinees vs placebo at all timepoints. Vaccinees reported fewer COVID-19 symptoms than placebo participants, and experienced shorter symptom duration, particularly for fatigue and difficulty breathing. Figure 1. SARS-CoV-2 spike IgG antibody titers upon SARS-CoV-2 infection by participant age in AZD1222 vaccinees and placebo recipients during illness visits Figure 2. Quantification of viral load (nasopharyngeal swabs quantitative viral titer) by SARS- CoV-2 variant at Illness Visit Day 1 Conclusion. Improved S Ab responses, lower viral loads, and reduced symptom burden upon breakthrough infection in vaccinees vs placebo recipients, suggest that robust recall responses to AZD1222 vaccination may attenuate COVID-19 disease severity and duration. These findings alongside data on cellular immune responses to breakthrough infection will inform understanding of protective immunity to SARS-CoV-2 infection.
ABSTRACT
A new mutated coronavirus named Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) was detected first time in Wuhan, China, in 2019. The novel SARS-CoV-2 causes a respiratory disease in humans called COVID-19. Currently, the COVID-19 spread globally with over 127 million confirmed cases, of which 110 million recovered with 27 million deaths. Several broad-spectrum antivirals, remdesivir, lopinavir/ritonavir, and arbidol and antimalarial drug hydroxychloroquine, have been suggested to treat COVID-19. However, now COVID vaccines are available for SARS-CoV-2. Alternatively, researchers have been searching for novel anti-SARS-CoV-2 phytochemicals from plants, to be used as a framework for the development of new therapeutic agents for COVID-19. For this, researchers have been performing large-scale screening of anti-SARS-CoV-2 phytochemicals using in-silico approaches, against the SARS-CoV-2 targets such as spike glycoprotein (S), chymotrypsin-like cysteine protease (3CLpro), papain-like cysteine protease (PLpro), and RNA-dependent RNA polymerase (RdRp). In this chapter, we have discussed in-silico approaches and their contribution to the robust screening of phytochemicals with anti-SARS-CoV-2 potential. © 2022 Elsevier Inc. All rights reserved.
ABSTRACT
COVID-19 pandemic has become a major challenge for all the countries of the world. No medicine has been developed till now to cure it. Coronavirus (COVID-19) is the family of viruses that causes illness and has symptoms like the common cold, influenza, and severe acute respiratory syndrome (SARS) that spread via breathing droplets. Proper analysis and prediction of the COVID-19 patients and its increasing rate of spread will help the government and people to mitigate its effect. This gives a reason to analyze, compare, and predict the cases in India, China, and SAARC countries to make early decision for taking preventive measures to combat its effects in a timely manner. In this paper, we have analyzed COVID-19 cases from January 21, 2020 to June 25, 2020 and have predicted the cases of COVID-19 for the period of next two weeks using multiple linear regression and polynomial regression models of machine learning. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
ABSTRACT
Objectives: COVID-19 pneumonia is documented to produce pulmonary thromboembolism. Despite achievingCOVID negative status, few patients continue to be symptomatic, especially with respiratory distress. This has beennoted particularly in those patients who had severe pulmonary involvement requiring high flow oxygenadministration at the time of admission. It often becomes challenging to correlate the clinical findings, D-dimervalues and ultrasonographic evaluation to rule out deep vein thrombosis related acute pulmonary embolism in thesepatients. Computed tomography pulmonary angiography has many limitations in assessing pulmonary embolism inthese patients as there are several other lung findings which can be seen in this cohort. Lung perfusion scintigraphywith SPECT/CT is a valuable tool in evaluation of pulmonary embolism. Lung perfusion scintigraphy in thesepatients, as a part of evaluation of pulmonary thromboembolism after recovering from COVID-19 pneumonia shows a multitude of findings. The aim of this exhibit is to acquaint the imaging physicians with these findings and henceimprove the diagnostic accuracy of pulmonary embolism in these patients. Methods: Records of lung perfusion scintigraphy with SPECT/CT done in patients with post COVID-19 pneumoniawere reviewed. Those patients who had severe symptoms clinically were reviewed for the imaging findings. Typicalperfusion finding of a wedge shaped perfusion defect in the planar imaging along with no lung parenchymal changesshould be easy to identify as well as strongly suggests the diagnosis of pulmonary embolism. However, somepatients might show difficult to interpret images in the planar and SPECT/CT imaging which requires careful analysisof both the perfusion and corresponding CT images. Results: Different possible findings of lung perfusion scintigraphy with SPECT/CT are presented. These includesclassical wedge shaped segmental defects in the planar as well as SPECT/CT imaging with (matched defects) orwithout (mismatched defects) corresponding various lung parenchymal findings (diffuse ground glassing, subpleuralground glassing, subsegmental cystic areas, parenchymal consolidation, fibrosis, interlobular reticulation) in the CTimages. Apart from the classical segmental defects, a good number of subsegmental perfusion defects are alsonoted in many cases, which poses a challenge in diagnosing the pulmonary embolism in these patients. Conclusions: In the wake of COVID-19 pandemic, ventilation scintigraphy carries an inherent risk of COVID-19exposure to the imaging personnel. However, the lung perfusion scintigraphy with added SPECT/CT imaging servesto overcome the deficiency of ventilation imaging. This exhibit illustrates the common and uncommon perfusion andcomputed tomography lung findings in those patients who recovered from COVID-19 infection and continue to besymptomatic, requiring supportive therapy. The knowledge of these findings will help the readers in interpreting theclinical and laboratory findings and correlate it with the lung perfusion imaging in any patient who have recoveredfrom COVID-19 infection. (Figure Presented).