Pfizer COVID-19 vaccine results positive, but questions remain

While Pfizer and BioNTech’s first interim analysis demonstrates the efficacy of their SARS-CoV-2 vaccine candidate, some questions remain.

The vaccine candidate, BNT162b2, demonstrated a 90% efficacy rate against COVID-19 in participants without prior evidence of SARS-CoV-2 infection, based on the first interim efficacy analysis conducted by an external, independent Data Monitoring Committee (DMC), the pharmaceutical manufacturers said in a press release.

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“We are reaching this critical milestone in our vaccine development program at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen,” said Albert Bourla, MD, Pfizer Chairman and CEO. “With today’s news, we are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis. We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks.”

In addition, the DMC has not reported any serious safety concerns and recommends that the study continue to collect additional safety and efficacy data as planned, Pfizer and BioNTech said.

While Pfizer and BioNTech’s vaccine candidate has “greatly exceeded the efficacy bar of 50% [for seasonal influenza vaccines] set by the FDA, several questions remain, said Philipp Rosenbaum, PhD, Senior Infectious Diseases Analyst at GlobalData, in a press release.

“The efficacy percentage could still decrease in the final analysis, and important questions about how well the vaccine can prevent severe cases of COVID-19, its effect on carriage and transmission of the virus, and the long-term protection will take many more months to be answered,” Rosenbaum said.

In addition, with 50 million doses available by the end of the year and 1.3 billion in 2021, “concerns about the supply and distribution of COVID-19 vaccines, especially for mRNA vaccine such as Pfizer’s that require deep-freeze storage and have a rather short shelf-life at refrigerator temperatures, will only add barriers,” he added.

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“Saying that, the speed of which this efficacy announcement has been made — a mere seven months after the companies started their first Phase I study — has been really quite impressive,” Rosenbaum said.

Dozens of other companies are also developing COVID-19 vaccines, and Phase 3 data from Moderna, AstraZeneca, and Johnson & Johnson, are expected soon, Rosenbaum added.

“Many manufacturing and supply deals have been made, and most of the companies already started manufacturing ahead of Phase III results. Having multiple vaccines available with even slightly lower efficacy would be immeasurably beneficial for controlling the outbreak, giving runway to ramping up manufacturing and bolstering of distribution channels for more effective vaccines,” Rosenbaum said.

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