Pfizer and BioNTech’s final Phase III COVID-19 vaccine analysis could decrease by 10 points from interim 90% data; vaccine could require testing to screen prior infection but rationale still theoretical

With Pfizer and BioNTech announcing that a Phase III trial investigating the BNT162b2 vaccine to be 90% effective in preventing symptomatic COVID-19 in participants without evidence of prior infection;

Reynald Castañeda, Pharma Writer for the Investigative News team at GlobalData, offers his view:


“The final Phase III efficacy analysis of Pfizer/BioNTech’s COVID-19 vaccine BNT162b2 is likely to show a decrease by around 5–10 points from the initial efficacy data owing to changes in volunteer demographics and waning efficacy.


“However, if the final data reports the vaccine is 50% effective, though worthy of an emergency use authorization (EUA) from the US Food and Drug Administration (FDA), the 40-point decrease would be a red flag to the vaccine’s durability. Yet, such a dramatic drop is unlikely because the initial data is high enough that the impact of potentially lower efficacy from forthcoming events would be diluted. The initial data is based on 94 cases, with a final efficacy analysis to occur when there are 164 events.


“Considering the interim analysis is based specifically on volunteers without prior evidence of SARS-CoV-2 infection, experts that I interviewed were divided as to whether vaccine receivers would need to be tested to screen for prior infection. While some experts noted a prior infection could impact vaccine efficacy or pose hypersensitivity to more severe symptoms, others said these concerns remain theoretical in nature.


“The initial data released on Monday captured the world’s, as well as the market’s, imagination in combatting the ongoing COVID-19 pandemic, triggering a 7.7% and 14% share price increase for Pfizer and BioNTech, respectively. BNT162b2 is likely to be granted an EUA by the FDA based on available data along with upcoming safety results, with the minimum bar being 50% efficacy.”

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