Pfizer vaccine appears effective against emerging SARS-CoV-2 variants Pfizer vaccine appears effective against emerging SARS-CoV-2 variants Share THE COVID-19 vaccine developed by Pfizer and BioNTech appears to be effective against emerging SARS-CoV-2 variants that spread more easily than other strains, early data suggest. Researchers from Pfizer and the University of Texas Medical Branch tested antibodies from 20 people who received the vaccine as part of a phase 3 trial against a lab-generated SARS-CoV-2 virus containing a mutation that allows the spike protein to bind more effectively to its receptor. The COVID-19 vaccine developed by Pfizer and BioNTech appears to work against variants of SARS-CoV-2 that make them more transmissible.