Washington, DC – June 20, 2021 – Although two variants of SARS-CoV-2 are associated with higher transmission, patients with these variants have no evidence of higher viral loads in their upper respiratory tract compared to the group witness, a Johns Hopkins School of Medicine study found.
The emergence and higher transmission of the evolutionary variants of SARS-CoV-2, the virus that causes COVID-19, is of concern. Researchers studied B.1.1.7, the variant first identified in the UK, and B.1.351, the variant first identified in South Africa, to assess whether patients had higher viral loads and, therefore, increased excretion and transmissibility.
Variants have been identified using whole genome sequencing. Researchers used a large sample cohort to show that the UK variant made up 75% of circulating viruses as of April 2021. Researchers compared 134 variant samples to 126 control samples and with access to patient clinical information. , were able to correlate genomics data with clinical disease and outcome. All samples underwent additional testing to determine their viral load. The information was associated with the stage of the disease by looking at the days after the onset of symptoms, which added clarity in the comparison of viral shedding between groups.
“It is not yet clear why these variants exhibit higher transmissibility,” said Adannaya Amadi, lead author of the study. “However, our results showed that patients infected with these variants are less likely to be asymptomatic compared to the control group. Although those infected with the variants do not have a higher risk of death or admission to care intensive, they were more likely to be hospitalized. “
This study was performed in the research lab of Dr. Heba Mostafa at the Johns Hopkins School of Medicine, who performed large-scale whole-genome sequencing of SARS-CoV-2 for the state of Maryland and contributed data publicly available national surveillance figures.
Alex Luo, C. Paul Morris, Matthew Schwartz, Eili Y. Klein, and Heba H. Mostafa also contributed to this work. The study was funded by the NIH, the Johns Hopkins Department of Pathology, Johns Hopkins University, and the Maryland Department of Health.
This summary will be presented at the World Microbe Forum online June 20-24, live from Baltimore, Maryland. World Microbe Forum is a collaboration between the American Society for Microbiology (ASM), the Federation of European Microbiological Societies (FEMS) and several other societies, which breaks down barriers to share science and address the most pressing challenges facing the humanity is facing today.
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