“We were hoping that we would get both the candidates, both products, Moderna and Pfizer rolled out by the week of the 20th. It is conceivable that we will only have one of them out,” Fauci told Face the Nation on Sept. 5. “The reason for that is that, as we’ve said right from the very beginning, we’re not going to do anything unless it gets the appropriate FDA [Food and Drug Administration] regulatory approval. And then the recommendation from the [Centers for Disease Control and Prevention’s (CDC)] Advisory Committee on Immunization Practices. Looks like Pfizer has their data in, likely would meet the deadline. We hope that Moderna would also be able to do it so we could do it simultaneously, but if not, we’ll do it sequentially.“ae0fcc31ae342fd3a1346ebb1f342fcb According to Reuters, on Sept. 1, Moderna submitted their initial documentation for a 50-mg booster to complement the initial two 100-mg shot regimen, noting that in a clinical trial, that dosage raised antibody levels against the Delta variant by more than 40-fold. Then, the company filed the remainder of its paperwork on Sept. 3. “We are pleased to announce that today we completed our submission to the @US_FDA, which we began on Wednesday, for the evaluation of a booster dose of the Moderna COVID-19 vaccine,” the company tweeted. Before the data was filed, a health official told the Associated Press (AP) on Sept. 3 that the FDA and CDC hadn’t seen enough data to approve a third dose of the Moderna vaccine and are waiting until more information becomes available before doing so. The source told the AP that approval for the third dose of Moderna will likely now come in October at the earliest. RELATED: Moderna Says These 3 Things Will Cause More Vaccinated People to Get COVID. As Fauci said on Face the Nation, Pfizer’s booster shot is expected to make the Sept. 20 deadline because the company began the approval processes earlier. Their data is to be reviewed by the FDA on Sept. 17. Bloomberg reported on Sept. 3, after Moderna submitted its final booster documentation, that it wasn’t clear whether a separate meeting would need to be scheduled to assess their data. But Fauci’s comments on Sept. 5 hint that’s a distinct possibility. Luckily, Pfizer has been the most widely distributed vaccine in the U.S., according to the CDC. The country has administered nearly 213 million doses of the Pfizer vaccine compared to 146.7 million of Moderna and 14.5 million of Johnson & Johnson (a much smaller number since it’s a one-dose regimen). But since Moderna recipients may not be able to get a third shot of Moderna specifically at that recommended eight-month mark, some are wondering if they should boost with Pfizer instead. On Face the Nation, reporter Weijia Jiang asked Fauci, “If I had the Moderna vaccine and I’m hearing that Pfizer is going to be available come September 20th, is it OK for me to mix and match?” “No, that’s a good question,” Fauci said. “We are doing studies right now, which are just what you said, they are mix and match studies. Namely, we’re lining up Pfizer against Pfizer, Pfizer for Moderna and vice versa. Hopefully within a reasonable period of time, measured in a couple of weeks, we will have that data. But right now, we are suggesting and hopefully it will work out that way, that if you got Pfizer, you will then boost with Pfizer. If you get Moderna, you’ll be boosting with Moderna. But we are doing the studies to determine if we can do just that—switch one with the other.” RELATED: For more up-to-date information, sign up for our daily newsletter. The CDC has also not yet approved a booster dose for the non-mRNA Johnson & Johnson vaccine. “Administration of the J&J vaccine did not begin in the U.S. until March 2021, and we expect more data on J&J in the next few weeks,” the U.S. Department of Health and Human Services (HHS) said in a statement on Aug. 18. “With those data in hand, we will keep the public informed with a timely plan for J&J booster shots as well.” The CDC and FDA have not recommended a mix-and-match approach to booster shots for those with the J&J vaccine. “There aren’t enough data currently to support getting an mRNA vaccine dose (either Pfizer-BioNTech or Moderna) if someone has previously gotten a J&J/Janssen vaccine,” the CDC advises on its website. “People who got the J&J/Janssen vaccine will likely need a booster dose of the J&J/Janssen vaccine, and more data are expected in the coming weeks.” Shortly before the announcement about the fall booster program, the CDC recommended that the U.S. begin administering third shots to people with moderately to severely compromised immune systems who were given the Pfizer or Moderna vaccines. As far as mixing and matching goes in this case, the CDC says: “For people who received either Pfizer-BioNTech or Moderna’s COVID-19 vaccine series, a third dose of the same mRNA vaccine should be used. … If the mRNA vaccine product given for the first two doses is not available or is unknown, either mRNA COVID-19 vaccine product may be administered.” RELATED: The Pfizer CEO Just Made This Chilling COVID Prediction.