Tuesday, July 21, 2020



Dr K Aggarwal
President CMAAO
With inputs from Dr Monica Vasudev

994:   When the prevalence of COVID-19 is high, even atypical imaging features are more likely to be COVID-19.

995: Typical chest CT findings in COVID-19 pneumonia include bilateral, peripheral and basal-predominant ground-glass opacities (GGOs) and/or consolidation, followed later by a mixed pattern of crazy paving, architectural distortion and perilobular abnormalities superimposed on GGOs that slowly resolve.

996: Upper lobe or peribronchovascular distribution of GGOs, cavitation, lymphadenopathy, and pleural thickening are found atypically

997: Other viral pneumonias can be more challenging to distinguish from COVID-19. For example, GGOs can be seen in up to 75% of adenovirus cases, more than 75% of cytomegalovirus and herpes simplex virus cases, and up to 25% of measles and human meta-pneumovirus cases. GGOs can be widespread in pneumocystis pneumonia, but, unlike in COVID-19, they tend to predominate in the upper lobes.

998: GGOs can also be common in hypersensitivity pneumonitis, lung injury from use of electronic cigarettes or vaping products, pulmonary edema, diffuse alveolar hemorrhage, pulmonary alveolar proteinosis, and eosinophilic pneumonia. But clinical features and GGO patterns are generally useful for differentiating these conditions from COVID-19.

999: Singapore scientists have uncovered T cell immunity specific to SARS-CoV-2 in recovered Covid-19 & SARS patients, and also in uninfected individuals. The study is published in Nature. T cells, along with antibodies, are part of the human immune response against viral infections. The T cells directly target and kill infected cells. In the study, the specific T cells were found in all subjects who recovered from SARS 17 years ago, and in over 50% of both SARS-CoV-1 and SARS-CoV-2 uninfected individuals tested. This suggests that a level of pre-existing SARS-CoV-2 immunity is present in the general population. They inferred that infection and exposure to coronaviruses induces long-lasting memory T cells, which could help in the management of the current pandemic. This could be due to cross-reactive immunity obtained from exposure to other coronaviruses, such as those causing the common cold. The researchers said it is important to understand if this could explain why some individuals are able to better control the infection. Source: Duke-NUS Medical School

1000: The incidence of stillbirth has increased since the COVID-19 pandemic began, according to a comparative study of pregnancy outcomes in a London hospital. This may have resulted from indirect effects such as reluctance to attend hospital when needed (e.g., with reduced fetal movements), fear of contracting infection, or not wanting to add to the National Health Service burden as reported by Dr Asma Khalil of St George's University of London in JAMA.

1001: A phase I/II trial of a vaccine against SARS-CoV-2 being developed by the University of Oxford has found that the vaccine is safe, causes few side effects, and induces strong immune responses. The early stage results, published in The Lancet, found that the candidate vaccine provoked a T-cell response peaking 14 days after vaccination, and an antibody response within 28 days. The trial, which has so far involved 1077 healthy adults, caused minor side effects when compared with a control group given a meningitis vaccine. Fatigue and headache were the most commonly reported reactions. However, there were no serious adverse events from the vaccine. The chimpanzee adenovirus viral vector vaccine (ChAdOx1) against the COVID-19 coronavirus is developed at Oxford University.

Phase II data on a competing vaccine from China, also using an adenovirus vector to deliver a gene encoding SARS-CoV-2 antigen, also indicated the product could be effective.
Phase I results on Moderna's mRNA vaccine published last week, all suggest that a vaccine -- and perhaps more than one -- to ameliorate the COVID-19 pandemic may soon be in reach.

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