SARS-CoV-2 Variants: Vaccine Neutralizes Virus with Key Mutation / FDA Warns of Theoretical Risk for False-Negatives

y Amy Orciari Herman

Edited by Susan Sadoughi, MD, and André Sofair, MD, MPH

Pfizer and BioNTech report that antibodies from people who’ve received the companies’ COVID-19 vaccine can neutralize SARS-CoV-2 carrying the N501Y mutation.

N501Y enables SARS-CoV-2’s spike protein to bind more tightly to its receptor. It’s found in some highly contagious variants, including the B.1.1.7 strain — the variant first identified in the U.K. and now detected in the U.S. (see CDC map linked below) and elsewhere.

In an in vitro study, posted on the preprint server bioRxiv, serum from 20 people who’d received two doses of vaccine neutralized SARS-CoV-2 with and without N501Y equally well. “This indicates that the key N501Y mutation … does not create resistance to the Pfizer-BioNTech vaccine induced immune responses,” the companies said in a news release.

Elsewhere, the FDA is cautioning healthcare providers that SARS-CoV-2 PCR tests may yield false-negative results if the part of the virus’s genome assessed by the tests mutates.

The agency has identified three molecular tests that may be affected by genetic mutations: the Accula SARS-Cov-2 Test, the TaqPath COVID-19 Combo Kit, and the Linea COVID-19 Assay Kit. The effect on the Accula test’s performance “does not appear to be significant,” the FDA says. Meanwhile, parts of the other two tests have significantly reduced sensitivity with some mutations, including one seen in the B.1.1.7 variant. Nonetheless, because the tests are “designed to detect multiple genetic targets, the overall test sensitivity should not be impacted,” the FDA says.

Providers are reminded to “consider negative results in combination with clinical observations, patient history, and epidemiological information.”