By Jack Denton 

U.S. residents ready for a Covid-19 booster shot may be able to get a different type of vaccine than the dose they initially received.

The Food and Drug Administration is moving to allow people to take a "mix-and-match" approach to vaccine boosters as soon as this week, according to reports from The Wall Street Journal and the New York Times that cited anonymous sources.

People can currently only receive a booster dose of the same vaccine they initially received. Last Friday, members of the FDA's vaccines advisory committee signaled a readiness to authorize mixed boosters.

The FDA won't recommend any one booster over another but will allow people to get a different dose than from their initial vaccination program, the reports said. The regulator may note that using the same vaccine as a booster is preferable when possible, according to the Times, which earlier reported the news.

Also read: FDA Vaccines Committee Seems Open to Mix-and-Match Boosters. What That Could Look Like.

The Journal report added that the FDA was on track to authorize the vaccines from Moderna (ticker: MRNA) and Johnson & Johnson (JNJ) as booster shots this week.

The regulator has already authorized booster shots of the vaccine from Pfizer (PFE) and its partner BioNTech (BNTX) for seniors and people at high risk of severe illness, as well as for those with compromised immune systems. The shot from Moderna has similarly been greenlit for immunocompromised people.

Allowing a mix-and-match approach has been touted by some health experts and authorities as a way to simplify the logistics of a booster shot rollout. It could also change the dynamics of the vaccine market.

As Barron's Josh Nathan-Kazis wrote last week, "data on the safety and efficacy of mix-and-match boosting will eventually determine how much room there is for other players in the Covid-19 vaccine market." If mix-and-match boosters are widely approved, it bodes well for the makers of Covid-19 vaccines still under development, such as Sanofi (SNY), Novavax (NVAX), and CureVac (CVAC).

Write to Jack Denton at jack.denton@dowjones.com