In the early days of vaccine rollout in the US, Pfizer somehow became the “status vaccine”—the subject of memes and funny jokes about the “hot guys” in the “Pfizer Gang.”
These tongue-in-cheek references came after results from preliminary clinical trials showed Pfizer had 95 percent efficacy against symptomatic infections, compared to Moderna’s 94 percent.
Meanwhile, health officials were adamant: Pfizer and Moderna’s supplements are equally effective, he said.
But as my colleague Apoorva Mandavilli reports, this has not turned out to be true.
Over the past few weeks, half a dozen studies have shown that Moderna’s vaccine appears to be more protective over the long term than Pfizer’s.
For example, research published last week by the CDC found that the efficacy of Pfizer’s vaccine against hospitalization fell from 91 percent to 77 percent after a four-month period after the second shot. Modern Shot did not show any decline in the same period.
Scientists who were initially skeptical of the reported differences have gradually become convinced that the disparity is small but real.
“Pfizer is a big hammer,” said Dr., an immunologist and physician at the University of Virginia in Charlottesville. Jeffrey Wilson said. “Modern is a sledgehammer.”
The results of studies on individual effects of vaccines can be skewed by any number of factors. For example, the Pfizer vaccine was introduced weeks ago to Moderna’s priority groups, including older adults. Immunity declines more rapidly in that group, so a decline in a group consisting mostly of older adults may give the false impression that protection from the Pfizer vaccine drops quickly.
Still, several studies — from Qatar, the Mayo Clinic and several US states — show Moderna’s efficacy against serious disease at 92 to 100 percent, while Pfizer’s numbers lag behind by 10 to 15 percentage points. In two other studies, Moderna Vaccine even outperformed in preventing infection — by more than 30 percentage points.
At the end of the day, there can be a real difference between the two vaccines, but how much will it matter in the real world?
“Probably not much,” Apoorva said. “Even though Pfizer-BioNtech lags slightly behind Moderna, the difference is mostly in protection against infection. When it comes to critical illness and hospitalization, both are still highly effective.”