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Virus World provides a daily blog of the latest news in the Virology field and the COVID-19 pandemic. News on new antiviral drugs, vaccines, diagnostic tests, viral outbreaks, novel viruses and milestone discoveries are curated by expert virologists. Highlighted news include trending and most cited scientific articles in these fields with links to the original publications. Stay up-to-date with the most exciting discoveries in the virus world and the last therapies for COVID-19 without spending hours browsing news and scientific publications. Additional comments by experts on the topics are available in Linkedin (https://www.linkedin.com/in/juanlama/detail/recent-activity/)
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Reduced Neutralizing Activity of post-SARS-CoV-2 Vaccination Serum Against Variants B.1.617.2, B.1.351, B.1.1.7+E484K and a Sub-Variant of C.37 | medRxiv

Reduced Neutralizing Activity of post-SARS-CoV-2 Vaccination Serum Against Variants B.1.617.2, B.1.351, B.1.1.7+E484K and a Sub-Variant of C.37 | medRxiv | Virus World | Scoop.it

Highly efficacious vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed. However, the emergence of viral variants that are more infectious than the earlier SARS-CoV-2 strains is concerning. Several of these viral variants have the potential to partially escape neutralizing antibody responses warranting continued immune-monitoring. Here, we tested a number of currently circulating viral variants of concern/interest, including B.1.526 (Iota), B.1.1.7+E484K (Alpha), B.1.351 (Beta), B.1.617.2 (Delta) and C.37 (Lambda) in neutralization assays using a panel of post-mRNA vaccination sera. The assays were performed with authentic SARS-CoV-2 clinical isolates in an assay that mimics physiological conditions.

 

We found only small decreases in neutralization against B.1.526 and an intermediate phenotype for B.617.2. The reduction was stronger against a sub-variant of C.37, followed by B.1.351 and B.1.1.7+E484K. C.37 is currently circulating in parts of Latin America and was detected in Germany, the US and Israel. Of note, reduction in a binding assay that also included P.1, B.1.617.1 (Kappa) and A.23.1 was negligible. Taken together, these findings suggest that mRNA SARS-CoV-2 vaccines may remain effective against these viral variants of concern/interest and that spike binding antibody tests likely retain specificity in the face of evolving SARS-CoV-2 diversity.

 

Preprint Available in medRxiV (July 23, 2021):

https://doi.org/10.1101/2021.07.21.21260961 

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Why Health Officials Are Watching New 'Lambda' Coronavirus Variant | Live Science

Why Health Officials Are Watching New 'Lambda' Coronavirus Variant | Live Science | Virus World | Scoop.it

A coronavirus variant known as "lambda" is gaining the attention of health officials as it spreads around the world. The variant, also known as C.37, was first detected in Peru in August 2020, according to the World Health Organization (WHO). On June 14, the agency designated C.37 a global "variant of interest," or VOI, and named it lambda. VOI means the variant is increasingly showing up in communities and has mutations that are predicted to have some effect on viral characteristics, such as increased transmissibility. In contrast, officials use the term "variant of concern," or VOC, once reliable data shows that the variant has increased transmissibility — such as what's been seen with the delta variant — or other worrying features. So far, lambda has been detected in 29 countries, with high levels of spread in South American countries. In recent months, the lambda variant was detected in 81% of COVID-19 cases in Peru that underwent genetic sequencing, according to the WHO. And in Chile, the variant was detected in about one-third of cases, the WHO said. 

 

Most recently, the variant popped up in the United Kingdom. On June 25, Public Health England reported six cases of the lambda variant, all of which were tied to overseas travel. Officials are monitoring the lambda variant because it carries a number of mutations that could potentially aid its spread. The variant has seven mutations in the virus's "spike protein" compared with the original strain of SARS-CoV-2 detected in Wuhan, China. Some of these mutations have the potential to increase transmissibility of the virus or to reduce the ability of certain antibodies to neutralize, or inactivate, the virus, according to the WHO. For example, lambda has a mutation known as F490S located in the spike protein's receptor-binding domain (RBD), where the virus first docks onto human cells. A paper published in the July issue of the journal Genomics identified F490S as a likely "vaccine escape mutation" that could both make the virus more infectious and disrupt the ability of vaccine-generated antibodies to recognize the variant.  Still, these effects are theoretical at this point. "There is currently no evidence that this variant causes more severe disease or renders the vaccines currently deployed any less effective," according to Public Health England. More studies are needed to see if these mutations really do affect how the virus behaves.

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