The FDA is alerting healthcare professionals that mutations in the novel coronavirus’s genetic code—such as the type powering the fast-spreading variant identified in the U.K.—can trigger false negative results in gold-standard COVID-19 tests.
Accuracy can suffer if the alterations occur within the specific region of the virus’s RNA used by molecular diagnostics to line up a positive result, which may vary product to product, the agency said.
While FDA staff said they believe these risks are low, the agency listed three currently authorized tests—Thermo Fisher’s TaqPath combo kit, Mesa Biotech’s hand-held Accula test and Applied DNA Sciences’ Linea assay—that may be compromised by genetic variants.
However, the detection patterns provided by the TaqPath and Linea tests could also help identify new mutated strains of the coronavirus, the FDA said—such as the new B117 variant, which could be 50% more contagious.
Tests that use multiple areas of the coronavirus’s genome to establish a positive match may offer more chances to pick up an accurate result, the agency said.
All viruses mutate over time, and the FDA is reevaluating all of its more than 200 authorized molecular tests—as well as certain vaccines and treatments—to see whether they will continue to work.
“At this time, we believe the data suggests that the currently authorized COVID-19 vaccines may still be effective against this strain,” FDA Commissioner Stephen Hahn, M.D., said in a statement.
“While these efforts continue, we are working with authorized test developers and reviewing incoming data to ensure that healthcare providers and clinical staff can quickly and accurately diagnose patients infected with SARS-CoV-2, including those with emerging genetic variants,” Hahn added.
This week, researchers from the University of Texas and Pfizer found that, in lab dishes, the company’s vaccine was able to neutralize an engineered version of the coronavirus with mutations in its spike protein.
Meanwhile, the Centers for Disease Control and Prevention (CDC) issued an order in late December requiring all inbound air passengers from the U.K. to be screened for COVID-19 before they board, including U.S. citizens—though the CDC said it expects the B117 variant to already be spreading among communities in several states.
While the variant has not yet proved to be more dangerous to individual patients, its higher rate of transmission could place additional burdens on the public health system as more people become infected.