GALVESTON, Texas – A collaborative team from The University of Texas Medical Branch at Galveston (UTMB) and Pfizer has shown that the common mutations of SARS-CoV-2 that have appeared in the United Kingdom and South Africa strains of the virus can be neutralized by the Pfizer COVID-19 vaccine. 
The study, using sera from 20 vaccine recipients, was published today in Nature Medicine.
Dr. Pei-Yong Shi of UTMB and Dr. Philip Dormitzer of Pfizer and colleagues engineered combinations of mutations found in these circulating variants and tested a panel of human sera obtained two or four weeks after immunization with two doses of the Pfizer/BioNTech vaccine.  Each sample was tested for its ability to neutralize the non-mutant strain of SARS-CoV-2 as well as the mutant viruses.
The authors found evidence of neutralization of the mutant viruses by the sera panel, with slight variation: neutralization against the E484K (South African) mutation was slightly lower than neutralization against the N501Y (U.K.) mutation.
“We used three genetically-engineered viruses that we built on the genetic background of the original strain we received from one of the first U.S. Covid patients.  The first included the N501Y mutation that is shared by both the U.K. and South African variants.  This mutation has been previously shown to increase binding and cell entry. The second clone included two additional changes found in the U.K. variant combined with the D614G mutation that is dominant in the strains currently circulating around the world.  A third strain contains a substitution that has shown resistance to several monoclonal antibodies.  All three comparisons showed plaque morphologies similar to that in the wild-type (WT) strain, and all sera showed equivalent neutralization titers between the WT and mutant viruses,” said Pei-Yong Shi of UTMB. “One limitation of the current study is that we have not included all the mutations from the spike gene of the new variants. Such experiments are ongoing.” 
The studies are part of a continuing collaboration between UTMB and Pfizer/BioNTech. 
Additional studies will help determine if transmission is increased as a result of the mutations. 
To implement this study, the UTMB team received funding from Pfizer, grants from the National Institutes of Health and philanthropic support from the Sealy & Smith Foundation; the Robert J. Kleberg, Jr. and Helen C. Kleberg Foundation; the John S. Dunn Foundation; the Amon G. Carter Foundation; the Gillson Longenbaugh Foundation; and the Summerfield G. Roberts Foundation.