The European Medicines Agency on Thursday identified severe allergic reactions as a potential side effect of Novavax Inc.'s COVID-19 vaccine.

The vaccine was authorized by U.S. regulators Wednesday, and its product label in the United States warns against administering the shot to people with a history of allergic reactions to any components of the shot. 

FAUCI ADMITS THAT COVID-19 VACCINES DO NOT PROTECT 'OVERLY WELL' AGAINST INFECTION

Novavax vaccine vile

A woman holds a small bottle labeled with a "Coronavirus COVID-19 Vaccine" sticker and a medical syringe in front of a Novavax logo in this Oct. 30, 2020, illustration. (REUTERS/Dado Ruvic/File Photo)

Shares of Novavax fell 20.3% to $55.72 in morning trading, along with the broader market and other COVID-19 vaccine makers. Novavax shares are usually volatile.

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The EMA said it would also update the product information for the vaccine to add unusual or decreased feeling in the skin as a new side effect.

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Only 250,000 doses of Novavax's COVID vaccine, Nuvaxovid, have been administered in Europe so far since its launch in December, according to the European Centre for Disease Prevention and Control.

COVID booster

A health care worker administers a booster dose of a COVID-19 vaccine at a temporary vaccine center in Guatemala City March 1, 2022. (AP Photo/Moises Castillo)

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