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The U.S. Food and Drug Administration (FDA) has OK'd the emergency use of a new monoclonal antibodies combination that may help prevent COVID-19 in two specific high-risk groups.

Here are some key questions and answers about AstraZeneca's Evusheld.

What is it?

Evusheld consists of two monoclonal antibodies (tixagevimab and cilgavimab) given as two shots. These proteins mimic the immune system's ability to fight off viruses. They target the spike protein of the coronavirus, which is what it uses to get into our cells.

Who is it for?

Evusheld is not a treatment for people who already have COVID-19 or who might have it due to a recent exposure. And it is not for those who are hesitant to get a vaccine. It is only authorized to prevent COVID-19 in certain people at high risk for infection because of one of two reasons:

• They have a moderately to severely compromised immune system. A weak immune system may not mount enough immune response to COVID-19 vaccines. A person can be immunocompromised due to certain health problems or treatments.
• They cannot be vaccinated because they have had a severe reaction to a COVID-19 vaccine or any of its ingredients.

Adults and children who fit into either group may have Evusheld, as long as the children are at least 12 years old and weigh at least about 88 pounds.

Does it work?

Because it targets the spike protein on the coronavirus, Evusheld may block the virus. In a clinical trial of 3,441 people, Evusheld was shown to reduce the risk of COVID-19 by 77%.

How often is it needed?

One dose (two shots given back to back) of Evusheld may offer protection for at least six months.

Are there side effects?

Like all medicines, Evusheld can have side effects. They may include:

• Allergic reactions.
• Bleeding at the site (usually the buttocks) where the shots are given.
• Headache.
• Tiredness.
• Cough.

What are the risks?

In its emergency use authorization (EUA), FDA said the benefits outweigh any risks.

In the clinical trial of Evusheld, more heart problems occurred among those who took it than among those who did not. But the heart problems were not common. And the people who had them were already at risk for heart disease prior to the study. So it's not clear if Evusheld caused the heart problems. Evusheld is still being studied.

Is it right for you?

In general, you should not have Evusheld if you don't have a weak immune system and you haven't had a previous bad reaction to a COVID-19 vaccine. Talk to your doctor to find out if Evusheld is right for you.

Remember: Evusheld is not a substitute for getting a COVID-19 vaccine if you are eligible. Being vaccinated and boosted is still the best protection.

Stay in the know

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Reviewed 4/25/2022