After Pfizer's pitch for 2nd round of COVID boosters, Moderna files a more ambitious FDA submission

How important is a second booster dose of a COVID-19 vaccine?

While experts have no clear consensus on this question, it’s likely to get increased attention in the coming weeks as Moderna has asked the FDA to authorize a second booster dose of its COVID-19 vaccine.

The move comes on the heels of a similar request from Pfizer and BioNTech for authorization of a second booster shot of their vaccine.

There’s a key difference in the applications, however. While Pfizer asked for a nod for its booster in people 65 and older, Moderna wants its second booster dose cleared for people 18 and older.

“The request to include adults over 18 years of age was made to provide flexibility for the (CDC) and healthcare providers to determine the appropriate use of an additional booster dose of mRNA-1273, including for those at higher risk of COVID-19 due to age or comorbidities,” Moderna said in its statement.

Moderna added that the submission is based in part on recent data from the United States and Israel following the emergence of omicron. In the Israeli study, while a fourth booster dose provided higher levels of protective antibodies, they weren’t enough to protect against omicron infection.

After a two-dose initial series, four weeks apart, of either the Moderna or Pfizer vaccine, people in the U.S. are recommended to receive a booster dose at least five months later. Data from both companies indicate that protection from the booster dose begins to wane after three to four months. Data from the CDC last month showed that protection against hospitalization begins to decrease four months from boosting.

Some Americans who received booster shots soon after they were approved in September (Pfizer) and October (Moderna) of last year are approaching six months since they were boosted.

“We know that the duration of the protection doesn’t last very long,” Pfizer CEO Albert Bourla said on Sunday on “Face the Nation.” “It is necessary, a fourth booster right now.”

Others contend that a stronger vaccine than Pfizer’s might be the answer. Bourla himself said that the company is working on a vaccine that would have more staying power.

“We obviously need to continue to work on the durability of protection, either by a boosting regimen … and/or perhaps using different platforms of vaccine that give a greater durability,” U.S. infectious disease expert Anthony Fauci recently said. “These things are just under consideration.”