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The Moderna booster shot may only be a half dose. Here’s why

The FDA might authorize a half dose of the Moderna COVID-19 vaccine because of the size of the original doses

Syringes are filled with the Moderna COVID-19 vaccine.
Syringes are filled with the Moderna COVID-19 vaccine at Salt Lake County’s mass vaccination site at the Mountain America Expo Center in Sandy on Monday, Jan. 18, 2021. The Food and Drug Administration may soon authorize half-dose booster shots for the Moderna coronavirus vaccine, Bloomberg reports.
Steve Griffin, Deseret News

The Food and Drug Administration may soon authorize half-dose booster shots for the Moderna coronavirus vaccine, Bloomberg reports.

Unnamed sources told Bloomberg that the FDA has seen data to suggest a half-dose would be enough to increase protection among Moderna vaccine recipients.

  • Moderna’s initial two-dose regime includes two 100-microgram doses. So the booster shot would be a 50-microgram dose.
  • Pfizer, for comparison, has two 30-microgram doses to start vaccination. The booster shot is a 30-microgram shot.

The half-dose decision could reduce the side effects of the shot, according to Bloomberg. And it would allow Moderna to distribute more doses throughout the world over the long term.

The Pfizer vaccine has already been authorized by the FDA for booster shots. People who are older than 65 years old or who have underlying conditions can get the booster shot now.

A study published in a letter to the Journal of the American Medical Association suggested that Moderna’s higher doses for the original two doses created more antibodies to fight off COVID-19. Moderna patients had about 2,881 antibody units per milliliter on average, whereas Pfizer patients averaged 1,108 units per milliliter in the study, as I wrote for the Deseret News.

Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said on NBC News’ “Meet the Press” last weekend that the Moderna and Johnson & Johnson booster shots will be coming soon.

  • “The actual data that we’ll get (on) that third shot for the Moderna and second shot for the J&J is literally a couple to a few weeks away,” he said. “We’re working on that right now to get the data to the FDA, so they can examine it and make a determination about the boosters for those people.”