(NEXSTAR) – A recent study that found the Moderna vaccine produced twice as many antibodies as Pfizer may be threatening Pfizer’s status as the “hot-person vaccine.” After all, who wouldn’t want all those extra antibodies coursing through their veins?
We asked two doctors whether they would pick Moderna over Pfizer if they hadn’t already been vaccinated.
“I’d say that the evidence now tilts toward Moderna being slightly more effective than Pfizer and may be holding up better over time,” says Dr. Bob Wachter, chair of the Department of Medicine at University of California, San Francisco.
But why is that, exactly? It’s hard to pinpoint what’s causing the antibody boost, says Dr. Peter Chin-Hong, an infectious disease expert at UCSF. “Pfizer and Moderna are essentially the same vaccines so it would be weird if they perform differently,” he says.
Chin-Hong posits Moderna’s advantage over Pfizer could be a difference in how its administered, not how it is made. People who get Moderna wait four weeks between a first and second dose; people who get Pfizer only wait three weeks. That extra week of waiting could result in the body producing a stronger antibody response.
Wachter suggests another factor at play: a higher relative dose of mRNA in the Moderna doses compared to Pfizer.
If you still haven’t been vaccinated, should the antibody boost sway your choice? Is Moderna the way to go?
“It does seem like a higher antibody level after vaccination is correlated with some enhancement in protection, and potentially durability,” says Wachter.
OK, but is Moderna twice as good? Not so fast.
“Remember that there are many other types of immune cells not measured that are not antibodies (like T cells) and there are many other places that are not in the bloodstream where immune cells hang out (like lymph nodes and bone marrow),” says Chin-Hong. “So I always take these antibody studies with a small grain of salt.”
The bottom line? “All three vaccines still robustly protect against serious disease, hospitalization, and death regardless of what antibody levels you can find in the bloodstream,” Chin-Hong says.