Scientists need to track genetic diversity of COVID-19 for effective vaccine: U of M study
In this June 26, 2020, file photo Healthcare professional Kenzie Anderson grabs a test tube for a sample at United Memorial Medical Center COVID-19 testing site in Houston. (AP Photo/David J. Phillip, File)
WINNIPEG -- A new study out of the University of Manitoba has determined that in order for the creation of an effective COVID-19 vaccine, experts must track the genetic diversity of the virus
The work, conducted by researchers at the Rady Faculty of Health Sciences and a virology lab at Universidad de Concepción in Chile, also found that if scientists don’t monitor how the virus is changing in different parts of the world, the testing could produce false negative results. Dr. Carlos Farkas, a postdoctoral researcher in pharmacology and therapeutics for the Max Rady College of Medicine and the Research Institute in Oncology and Hematology, was the study’s lead author.
To conduct the study, the research team used datasets to look at whole genome sequencing samples from people infected before March 27 with the virus that causes COVID-19.
According to a news release from the university, this team “was the first to combine genomic sequencing data from two worldwide sources in order to detect variants by geographic region.” The group found 146 different variants.
Dr. Jody Haigh, co-author and associate professor of pharmacology and therapeutics and a senior scientist at the Research Institute in Oncology and Hematology, said one of the major findings was that samples from Washington had a distinctive footprint of viral sequence changes.
“About 39 per cent of Washington State samples had this footprint. Asian and European samples were more diverse in terms of changes in viral sequence, but their footprints were clearly different from those in the U.S. samples,” Haigh said in the release.
The researchers noted when labs test for SARS-CoV-2 (the virus that causes COVID-19), they use small pieces of DNA that bind to the viral sequence and amplify viral RNA/DNA.
Farkas said in order for a robust positive test result, the DNA needs to exactly match the viral sequence.
“If researchers design these primers to bind to regions of the virus that they don’t realize have changed in a particular population, there may be poor amplification and the result can be false negatives,” Farkas said.
The study did find some changes in viral sequence in regions of the virus where the DNA was supposed to bind, which could explain why there have been some false negative testing results.
“Because SARS-CoV-2 is changing rapidly, researchers should be aware of its current local viral footprints in order to design DNA primers that don’t bind to regions of the virus that have changed. Other regions of the virus that don’t show these changes should be used for designing primers,” Haigh said.
The research team hopes its work will impact COVID-19 testing and vaccine development.