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Moderna in Conversation with FDA to Add Doses to COVID-19 Vaccine Vials

Moderna vials

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Key Takeaways

  • Moderna is in conversation with the FDA to add five more doses to each COVID-19 vaccine vial, which could increase the number of people who can be vaccinated at each site each day. 
  • Even if Moderna gets the OK to add doses to vials, the increased supply is not expected for a few months. 
  • Pfizer does not plan to add doses to its vials.

Moderna is working with the Food and Drug Administration (FDA) to add more doses to each COVID-19 vaccine vial, increasing the volume from 10 to 15 doses per vial.

Moderna confirmed the news to Verywell in a February 17 email. The added doses could increase how many shots vaccination sites are able to administer in a single day.  

“As manufacturing scale-up for the Moderna COVID-19 Vaccine continues, the Company has continuously explored approaches to potentially improving throughput in 2021,” the Moderna spokesperson wrote. “Moderna has proposed filling vials with up to 15 doses of vaccine versus the previous 10 doses. Moderna continues to engage in discussions with the FDA and regulatory authorities in other countries about this potential increase in fill volumes, thus enabling extraction of additional doses from each vial delivered.”

Moderna says it will take two to three months to implement these changes if approved.

While that’s a ways off, those extra doses could come in April or May when many communities are expected to expand vaccine eligibility to a wider group of people. Each new vial requires a few minutes to prepare for use. If healthcare workers can open fewer, fuller vials to get the job done, they'll be able to vaccinate more people faster.

“I think it’s a great idea if they’re able to add the doses,” says Jason Gallagher, PharmD, a clinical professor at the Temple University School of Pharmacy in Philadelphia, Pennsylvania, who volunteers once a week administering COVID-19 vaccines.

Not the First Instance of Extra Doses

Gallagher tells Verywell that Moderna fills its vials with the currently-approved 10 doses, but all vaccine manufacturers add just a bit more of the fluid to account for possible micro spills when the syringe is filled. Early on in the vaccine administration process, some immunizers found that by using a low dead-space syringe—which has less space between the syringe hub and needle—they could extract an eleventh dose in Moderna vials.

During a press briefing, White House COVID-19 response coordinator Jeffrey Zients said the Biden administration is working to secure sufficient supplies of the specialized syringes. 

Gallagher thinks Moderna is working with the FDA to add more doses because they're a new company making a vaccine for the first time—they may still be sorting out how to optimize their vials.

Pfizer, on the other hand, has been in the vaccine business since the late 1800s. Pfizer seems to have filled its vials higher than Moderna to begin with, and is not asking the FDA for permission to add more doses to its vials, which currently fits six.

As with Moderna, some immunizers were able to extract an extra dose in the early days of COVID-19 vaccinations by using the specialized syringes. While the vaccine launched with labeling for five doses, it was quickly bumped up to six.

Jerica Pitts, a spokesperson for Pfizer, tells Verywell via email that the sixth dose was planned.

“The expansion of the Pfizer COVID-19 vaccine to six doses per vial from five was purposeful and it did not occur by chance,” she says. “Before the summer of 2020, our CEO had already asked our scientific team to work on reducing waste and increase the number of doses per vial. At the time we submitted our first regulatory applications we did not yet have validation data on six doses. In order to avoid delays, we submitted the available data at the time for five doses. Once the data supporting six doses became available, we immediately submitted it to all regulatory authorities around the world. So far, the six-dose label has been approved by many regulatory agencies around the world including the FDA."

The FDA revised its fact sheet for the Pfizer vaccine in January to say that after dilution, one vial contains six doses of 0.3 mL, even if the label on a vial or carton says it contains five doses.

"During this pandemic, with the number of people dying across the globe, it is critical that we utilize all available vaccine supply and vaccinate as many people as possible," Pitts says. "To leave an additional dose in each vial that could be used to vaccinate additional people would be a tragedy.”  

What This Means For You

You may hear that pharmacists are extracting “extra” doses from COVID-19 vaccine vials. It's important to know the manufacturers have FDA clearance for those doses. If the final extra dose comes up even slightly short, the guidance is to open a brand new vial for the next shot.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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  1. Pfizer. A legacy of achievement in preventing disease.

  2. U.S. Food & Drug Administration. Fact sheet for healthcare providers administering vaccine (vaccination providers) emergency use authorization (EUA) of the Pfizer-BioNtech COVID-19 vaccine to prevent coronavirus disease 2019 (COVID-19). Updated January 2021.