Pfizer plans a first look at the data after a mere 32 coronavirus infections have accumulated in the massive 44,000-person trial. That case total, far short of the final goal of 164, could be reached as soon as Sept. 27, by some estimates.
The company has also given given itself four chances to get a preliminary result. Some trial experts say the company appears to be looking for a leg up in a race to be first with a vaccine.
“I’ve never seen a trial where there were four interim analyses; that may be the Olympic record,” said Eric Topol, editor-in-chief of Medscape, a website offering clinical information for health-care professionals, and director of the Scripps Research Translational Institute in La Jolla, California. “It’s obvious why it is being done: so you can just keep looking at the data to try to win a race.”
All the drugmakers’ trials will count people with Covid-19’s most common symptoms—such as cough and fever—as cases, if they test positive for the virus. The rush for results raises the concerns that a vaccine may be authorized mostly on the basis of whether it prevents mild symptoms.
“We want to know this vaccine has strong efficacy,” Topol said. “And that means two things: that it works in the majority of people and that it works to prevent serious infections, not sore throats or muscle aches.”