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1.
PubMed; 2021.
Preprint in English | PubMed | ID: ppcovidwho-296585

ABSTRACT

Characterizing SARS-CoV-2 evolution in specific geographies may help predict the properties of variants coming from these regions. We mapped neutralization of a SARS-CoV-2 strain that evolved over 6 months from the ancestral virus in a person with advanced HIV disease. Infection was before the emergence of the Beta variant first identified in South Africa, and the Delta variant. We compared early and late evolved virus to the ancestral, Beta, Alpha, and Delta viruses and tested against convalescent plasma from ancestral, Beta, and Delta infections. Early virus was similar to ancestral, whereas late virus was similar to Beta, exhibiting vaccine escape and, despite pre-dating Delta, strong escape of Delta-elicited neutralization. This example is consistent with the notion that variants arising in immune-compromised hosts, including those with advanced HIV disease, may evolve immune escape of vaccines and enhanced escape of Delta immunity, with implications for vaccine breakthrough and reinfections. Highlights: A prolonged ancestral SARS-CoV-2 infection pre-dating the emergence of Beta and Delta resulted in evolution of a Beta-like serological phenotypeSerological phenotype includes strong escape from Delta infection elicited immunity, intermediate escape from ancestral virus immunity, and weak escape from Beta immunityEvolved virus showed substantial but incomplete escape from antibodies elicited by BNT162b2 vaccination. Graphical abstract:

2.
PubMed; 2021.
Preprint in English | PubMed | ID: ppcovidwho-296584

ABSTRACT

The emergence of the SARS-CoV-2 Omicron variant, first identified in South Africa, may compromise the ability of vaccine and previous infection (1) elicited immunity to protect against new infection. Here we investigated whether Omicron escapes antibody neutralization elicited by the Pfizer BNT162b2 mRNA vaccine in people who were vaccinated only or vaccinated and previously infected. We also investigated whether the virus still requires binding to the ACE2 receptor to infect cells. We isolated and sequence confirmed live Omicron virus from an infected person in South Africa. We then compared neutralization of this virus relative to an ancestral SARS-CoV-2 strain with the D614G mutation. Neutralization was by blood plasma from South African BNT162b2 vaccinated individuals. We observed that Omicron still required the ACE2 receptor to infect but had extensive escape of Pfizer elicited neutralization. However, 5 out of 6 of the previously infected, Pfizer vaccinated individuals, all of them with high neutralization of D614G virus, showed residual neutralization at levels expected to confer protection from infection and severe disease (2). While vaccine effectiveness against Omicron is still to be determined, these data support the notion that high neutralization capacity elicited by a combination of infection and vaccination, and possibly by boosting, could maintain reasonable effectiveness against Omicron. If neutralization capacity is lower or wanes with time, protection against infection is likely to be low. However, protection against severe disease, requiring lower neutralization levels and involving T cell immunity, would likely be maintained.

3.
Arab Journal of Basic and Applied Sciences ; 28(1):225-233, 2021.
Article in English | Scopus | ID: covidwho-1246678

ABSTRACT

Coronavirus disease (COVID-19) is a communicable disease caused by a recently discovered coronavirus. The disease was first reported in Wuhan, China at the end of 2019 and has resulted in 1.71 million global deaths and over 77 million infections. Common symptoms of the disease include fever, dry cough, and fatigue. This literature review aims to summarize the following topics: review the clinical trials conducted on nine COVID-19 vaccines and follow their efficacy and modes of action through the three stages of the vaccine clinical development process. The analysis follows the individual vaccines through the three trials, examining and analysing drawn results to identify their capacity to contain severe acute respiratory syndrome (SARS-CoV-2). Four COVID-19 vaccines have been approved for use in different parts of the world and many other vaccines are under clinical trials 1, 2 and 3. In conclusion, these vaccines which are under clinical trials provide a great hope to fight against COVID-19 in near future. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the University of Bahrain.

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