Pfizer Inc. and BioNTech SE announced results from in vitro neutralization studies of sera from individuals vaccinated with the Pfizer-BioNTech COVID-19 vaccine. The sera neutralized SARS-CoV-2 with key mutations present in the United Kingdom (U.K.) and South Africa variants, as measured by studies conducted by Pfizer and the University of Texas Medical Branch (UTMB). The results were published on the preprint server bioRxiv and submitted to a peer-reviewed journal.

To study the effect of these mutations, three engineered viruses with key mutations were tested against the panel of human sera from 20 participants in the previously reported Phase 3 trial who had been immunized with the Pfizer-BioNTech COVID-19 vaccine. Of the three recombinant variants, one has a mutation common to both the U.K. and South Africa variants (N501Y), one has mutations common to the U.K. variant (?69/70+N501Y+D614G), and the third has mutations common to the South Africa variant (E484K+N501Y+D614G). The sera from individuals vaccinated with the Pfizer-BioNTech COVID-19 vaccine neutralized all the SARS-CoV-2 strains tested.

Consistent with recent reports of the neutralization of variant SARS-CoV-2 or corresponding pseudoviruses by convalescent or post-immunization sera,1,2 neutralization against the virus with the three key mutations present in the South African variant (E484K+N501Y+D614G) was slightly lower when compared to neutralization of virus containing the other mutations that were evaluated. However, the Companies believe the small differences in viral neutralization observed in these studies are unlikely to lead to a significant reduction in the effectiveness of the vaccine. Pfizer and BioNTech are encouraged by these early in vitro study findings and are currently evaluating the full set of mutations in the spike protein of the South African variant.

While these findings do not indicate the need for a new vaccine to address the emerging variants, the Companies are prepared to respond if a variant of SARS-CoV-2 demonstrates evidence of escaping immunity by the COVID-19 vaccine. Pfizer and BioNTech will continue to monitor emerging SAR-CoV-2 strains and continue to conduct studies to monitor the vaccine's real-world effectiveness. Pfizer and BioNTech believe that the flexibility of BioNTech's proprietary mRNA vaccine platform is well suited to develop new vaccine variants if required.

The Pfizer-BioNTech COVID-19 Vaccine has not been approved or licensed by the U.S. Food and Drug Administration (FDA), but has been authorized for emergency use by FDA under an Emergency Use Authorization (EUA) to prevent Coronavirus Disease 2019 (COVID-19) for use in individuals 16 years of age and older. The emergency use of this product is only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of the medical product under Section 564 (b) (1) of the FD&C Act unless the declaration is terminated or authorization revoked sooner.