Pfizer and Moderna haven't proven their COVID-19 vaccines shield against new variants: analysts

Just as the U.S. government is starting to ramp up purchases of Pfizer’s and Moderna’s mRNA vaccines to prevent COVID-19, a troubling question is emerging in the scientific community: Can these shots protect people against aggressive new variants racing through the U.K., South Africa and Brazil?

Several analysts have scoured the medical literature and interviewed infectious disease experts in an effort to answer that question. Their conclusion? There is no clear answer. At least not yet.

When it comes to SARS-CoV-2, the virus at the heart of the pandemic, “we are in a state of ignorance with incomplete data,” said SVB Leerink analyst Geoffrey Porges in a note to clients Wednesday. He reached that conclusion after interviewing an infectious disease specialist who is also an official with the FDA, he said.