What to Know About Monoclonal Antibodies for COVID-19

What Are Monoclonal Antibodies?

They are a type of medical treatment. Scientists make monoclonal antibodies, or mAbs, in a lab. They work like the natural antibodies your body makes to fight illness. They go out into your body to identify and attack germs like the coronavirus that causes COVID-19. Research seems to show that some mAbs, when used correctly, may help some people with COVID-19.

How Do Monoclonal Antibodies Work?

To make monoclonal antibodies, scientists expose a specific type of cell from the immune system to a particular viral protein -- in this case, SARS-CoV-2, the virus that causes COVID-19. They can then design the mAb to target a particular virus or a specific part of the infection process.

For COVID-19, scientists made several mAbs that bind to the spike protein on the virus’s surface. This stops the virus from invading human cells.

The FDA has given emergency use authorization, or EUA, for several of these medicines. That means doctors can use them in certain cases, even though they haven’t been through the full FDA approval process. EUA-approved mAbs for COVID-19 include:

  • Casirivimab and imdevimab, given together (known as REGEN-COV)
  • Sotrovimab:

In April 2021, the FDA withdrew EUA for bamlanivimab alone because more variants of the COVID-19 virus were becoming resistant to the drug. In January, 5% of variants were resistant to bamlanivimab alone. By mid-March, it was 20%. In June, the FDA paused it's EUA for the combination use of bamlanivimab and etesevimab.

Other mAbs and combinations of mAbs seem to work more broadly against most variants of the COVID-19 virus. Scientists continue to carefully watch how well mAb treatments work against variants of SARS-CoV-2.

Who Gets mAbs for COVID-19?

Doctors can use these medicines to treat mild to moderate COVID-19 if all of the following are true:

  • You’re an adult or a child 12 or older that weighs at least 88 pounds.
  • You test positive in direct SARS-CoV-2 viral testing.
  • You’re at high risk for serious symptoms or hospitalization from COVID-19.

If you meet the above conditions, your doctor can treat you with mAbs as long as they have medications to treat an allergic reaction and are ready and able to give emergency care, if needed.

Doctors seem to find the most benefit from mAbs in people with COVID-19 who aren’t sick enough for hospital care but have risk factors for serious infection. These might include:

  • Being older than 65
  • A suppressed immune system
  • Certain medical conditions
  • Obesity

See your doctor as soon as possible if you have COVID-19 symptoms and think you could be a candidate for mAbs because early treatment is key to their success.

WebMD Medical Reference Reviewed by Michael W. Smith, MD on May 04, 2021



Centers for Medicare & Medicaid Services: “Monoclonal Antibody COVID-19 Infusion.”

European Medicines Agency: “EMA reviewing data on monoclonal antibody use for COVID-19.”

FDA: “Coronavirus (COVID-19) Update: FDA Revokes Emergency Use Authorization for Monoclonal Antibody Bamlanivimab.”

Journal of the American Medical Association: “Monoclonal Antibodies for COVID-19.”

NIH COVID-19 Treatment Guidelines: “Anti-SARS-CoV-2 Monoclonal Antibodies.”

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