Moderna says COVID booster shows effectiveness against Omicron

Dec 21 , 2021. 3 hours ago – 07:01 KYODO NEWS

WASHINGTON – U.S. biotechnology firm Moderna Inc. said Monday that a third shot of its coronavirus vaccine has been shown in a laboratory test to significantly increase antibodies that would fight off the highly transmissible Omicron variant.

As the United States is seeing another surge in coronavirus cases, the U.S. capital said the same day it is reinstating its indoor mask mandate beginning Tuesday.

The study by Moderna showed that a two-dose course of the vaccine, with each shot containing 100 micrograms, provided only low levels of antibodies. But the currently authorized 50-microgram booster increased the antibody levels to around 37-fold 29 days after inoculation.

Given the strength of the vaccine and the speed at which the Omicron variant is spreading, Moderna’s “first line of defense against Omicron will be a booster dose,” the company said.

The study also showed that a 100-microgram booster shot increased antibody levels approximately 83-fold, and was found to be “generally safe,” it said.

The side effects seven days after receiving a booster were also “generally comparable to those seen after the two-dose primary series,” but adverse reactions were seen slightly more frequently following the 100-microgram shot relative to the 50-microgram dose.

Moderna said it will continue to develop an Omicron-specific vaccine, given the “long-term threat” demonstrated by the new variant’s immune escape, expecting to advance into clinical trials in early 2022.

The announcement came after U.S. pharmaceutical giant Pfizer Inc. said earlier in the month that a third shot of its COVID-19 vaccine can increase antibodies by 25-fold, providing a similar high level of protection as observed with the two-dose series before the emergence of the new variant.