The FDA issued an emergency use authorization for the Novavax Covid-19 vaccine, giving Americans 18 and older a fourth vaccine choice.

In this photo illustration, silhouette of hands in medical...

There is a silhouette of hands in medical gloves holding a medical device.

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The Novavax vaccine schedule consists of two doses three weeks apart and has a small Covid-19 "spike" that teaches the immune system to recognize and fight off future infections.

There were no cases of moderate or severe Covid-19 in the 17,200 people who received the vaccine.

One in five Americans have not received a first Covid-19 vaccine because they are resistant to the Novavax vaccine.

Dozens of countries and the European Union have approved the use of the vaccine. The Biden administration secured more than three million doses of Novavax for distribution. Manufacturing issues hampered the development of the vaccine. The new form of Covid-19, called the BA.5 omicron subvariant, was the main cause of new infections and hospitalizations in the US, according to the CDC.

The U.S. secures more than three million Novavax Covid Vaccines.

As Covid Cases Rise, the Highly Contagious BA.5 variant becomes dominant in the U.S.