Experts said Thursday that researchers need to do more genomic sequencing of COVID-19 patient samples to track the spread of new coronavirus strains -- which appear to spread faster, and could delay herd immunity. File Photo by Jim Ruymen/UPI | License Photo
Feb. 18 (UPI) -- The United States must continue to ramp up surveillance efforts designed to spot new variants of the coronavirus to contain the pandemic, experts said Thursday.
The U.S. Centers for Disease Control and Prevention has recently expanded screening of virus samples for new genetic mutations that may affect how quickly it spreads and whether vaccines will work against it.
Through early January, just 0.3% of 18.2 million samples, or around 51,000, collected from U.S. COVID-19 patients underwent genomic sequencing -- genetic analysis designed to spot mutations or changes in the virus DNA -- according to Johns Hopkins University in Baltimore.
As of this week, the CDC said it is analyzing about 4,500 of the roughly 100,000 new cases of COVID-19 identified each day.
Although new variants or strains of the virus may not necessarily cause more severe symptoms of COVID-19 or render existing vaccines useless, research suggests they spread much faster, virologist Andy Pekosz said.
"And more cases means there will be more sick people," said Pekosz, co-director of the Johns Hopkins Center of Excellence for Influenza Research and Surveillance, during a conference call with reporters.
All viruses mutate, and the coronavirus, which causes COVID-19, is no exception.
Tracking how these mutations affect spread of the virus or how it evades the immune system once people have been exposed or vaccinated, however, requires broad-based genomic sequencing, according to Pekosz.
Although that effort has been ramped up dramatically in recent weeks with the emergence of the more contagious strains, it is still not sufficient to contain them, said Pekosz and his colleague, immunologist Gigi Gronvall, who also was on the call.
Britain has sequenced more than 7% of collected samples, Johns Hopkins experts estimate.
In January, the CDC predicted that the B.1.1.7, or British, variant could become the "predominant" one circulating in the United States by the end of March.
Through Tuesday, just over 1,200 known U.S. cases were caused by the variant, said Gronvall, an associate professor of environmental health and engineering at the Johns Hopkins Bloomberg School of Public Health.
The CDC reported 19 cases of the B.1.351, or South African, variant and one case of the P.1, or Brazil, variant reported in the United States so far.
However, those could be significant underestimates, given the lack of genetic testing currently being done, Gronvall said.
"We have not done a great job of sequencing the clinical isolates to this point [so] it's fully possible there are more of these variants, as well as other variants, out there," Gronvall said.
A report issued earlier this week by Pekosz and Gronvall's colleagues at Johns Hopkins calls for a national genomic surveillance strategy to better identify new strains of the coronavirus and contain outbreaks.
Although research to date suggests that the vaccines from Pfizer-BioNTech and Moderna are effective against the so-called "U.K. variant," the studies have been limited in size and scope.
Still, immunity derived from prior exposure to other strains of the coronavirus, or from vaccination, should continue to "lower the number of people susceptible to the virus and reduce the spread of the virus" in the United States, Pekosz said.
"The variants aren't magic -- masks still work, the tests still work [and] research indicates the vaccines ... still work," Gronvall said.