How Do the Pfizer and Moderna COVID-19 Vaccines Compare?

As it currently stands, a pair of mRNA vaccine candidates seem most likely to submit the first Emergency Use Authorization (EUA) applications to the US Food and Drug Administration (FDA) for the prevention of coronavirus 2019 (COVID-19).

Pfizer’s BNT162 and Moderna’s mRNA-1273 have both been linked to preliminary phase 3 data showing 90% efficacy or greater among administered patients versus placebo arms at the first cutoff for total infection rates in their respective global, large-scale trials.

Though there is much more to be shared in clinical outcomes—including patient demographic-stratified efficacy which could speak to the discriminate effect of COVID-19, as well as general patient safety data—the anticipation is that one of these 2 vaccines will be the first indicated and distributed for use in the US for the pandemic.

That’s not to imply, however, there’s substantial comparators between the 2 candidates.

In an interview with Contagion, Sam Fazeli, senior pharmaceutical analyst for Bloomberg Intelligence, discussed the need for greater insight before picking distinctions between BNT162 and mRNA-1273.

In fact, as he noted, if the most critical difference is set by currently reported efficacy points, matters could change in matter of weeks given infection rates.

“These are such small numbers that a couple more in each arm as the trial continues will impact the final read,” Fazeli said. “The assumption has to be when these vaccine trials get to the end of their primary endpoints, they’ll be in pretty good positive territory in their percentages—even if everything goes wrong.”

Fazeli also discussed his own interest in severity outcome data, as well as how either vaccine fares in differing patient age groups. Noting benefits for one or the other, he pointed to Moderna’s early reported marks in T-cell activation and older-patient antibody responses, as well as the biotechnology company’s involvement from the National Institutes of Health (NIH) and Anthony Fauci, MD.

To Pfizer’s benefit, they have a history in vaccine development and distribution. A missing facet of research still is how these candidates will be adequately stored and administered.

“If they can convince the regulators that they can manufacture…as long as the data supports it, I think the rest of it should be equal,” Fazeli said.