COVID-19 and Antibodies: What You Need to Know About Treatment

Susan L. Smith, MN, PhD Disclosures Published on Mar 9, 2021

This article is for anyone who wants to learn more about coronavirus disease 2019 (COVID-19). The goal of this patient education activity is to improve knowledge about how neutralizing antibodies are used to treat COVID-19.

You will learn about:

COVID-19 and how your immune system works to protect you
What neutralizing and monoclonal antibodies are
How neutralizing monoclonal antibodies may be used to treat COVID-19
Questions to ask your doctor

Medicines listed in this activity have either a US Food and Drug Administration (FDA) approval or have been given an Emergency Use Authorization (EUA) by the FDA to treat or prevent COVID-19.

The information on COVID-19 is continually changing. The content in this activity is accurate based on the information that was available at the time of its publication. This resource is provided for educational and informational purposes only. We do not provide medical advice, diagnosis, or treatment.

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COVID-19 Overview

COVID-19 is an illness caused by a type of virus called a coronavirus. Exposure to the virus can cause an infection that usually starts in the upper respiratory tract (nose, sinuses, and throat). Because this specific coronavirus is new -- or novel -- and we haven't been exposed to it before, COVID-19 is a new disease for humans.

COVID-19 is mainly spread by droplets in the air that form when someone who's infected talks, coughs, or sneezes. The virus then infects someone else when the droplets enter their mouth, nose, or eyes.

How Sick Can You Get From COVID-19?

Most people with COVID-19 have mild or no symptoms and recover fairly quickly. But for others, it can cause severe illness and even death. Anyone can get COVID-19, but it is especially dangerous for those who have certain medical conditions, smoke, are pregnant, or are elderly.

COVID-19 can damage many different body systems and organs. Because of this, it can cause complications (additional problems) and symptoms that may be long lasting.

If you think you've been exposed to COVID-19, contact your doctor. Stay home, separate from others, and watch for symptoms. If you develop severe symptoms, such as trouble breathing, get emergency help right away.

Your Immune System Helps Protects You

Your immune system is your body's natural defense system. It's made up of different organs -- including bone marrow and lymph nodes -- cells, and proteins that work together to help protect you when you're exposed to outside invaders, such as bacteria and viruses. This includes the virus that causes COVID-19.

The 2 main parts of the immune system are:

Innate -- the part that's inherited (passed on from your parents) and is active when you're born
Adaptive (or acquired) -- the part that you develop over time as your body is exposed to outside invaders

The Role of Antibodies

When you're exposed to an outside invader, such as a virus, your immune system is triggered and activates certain proteins and cells. These include B cells, a special type of white blood cell. These cells make proteins called antibodies that are released into your bloodstream to attack the invader and fight off infection.

It can take several days for antibodies to develop. But they stay in your body and can help your immune system recognize and defend against the invader if you're exposed to it again.

How Antibodies Can "Neutralize" a Virus

A virus can't reproduce, or make more viruses, on its own. It needs to attach to and enter, or infect, healthy cells in order to do so.

When an antibody attacks a virus, it usually binds to the areas on the virus that it uses to attach to and enter cells. This way, the antibody can stop -- or neutralize -- the virus and protect the cells from infection. Antibodies that work like this are called neutralizing antibodies. How well an antibody works often depends on how strongly and where on the virus it binds.

Antibodies (in white) can attack and bind to areas on a virus (in red) to neutralize it.

What Is a Monoclonal Antibody?

Antibodies can be natural (made by your body) or monoclonal (made in a lab from natural sources). Monoclonal antibodies are designed to attack invaders, such as viruses, like your natural antibodies do to fight off infection.

Neutralizing antibodies can be natural or monoclonal. Some neutralizing monoclonal antibodies can be given to someone who has a high risk of infection to try and treat or prevent a disease.

Neutralizing Monoclonal Antibodies and COVID-19

Certain neutralizing monoclonal antibodies have been made to treat COVID-19. They're designed to tightly bind to specific areas on the virus that causes COVID-19, stopping it from attaching to and entering healthy cells.

These neutralizing monoclonal antibodies are medicines used for people who are not hospitalized (not sick enough to be in the hospital) but have mild to moderate COVID-19 symptoms and are at a high risk for severe symptoms or the need to be hospitalized. Some of these medicines may be given together, as a mixture of 2 different neutralizing monoclonal antibodies, to bind to more than one site on the virus.

Neutralizing Antibodies Work Differently Than Vaccines

Neutralizing monoclonal antibodies work differently than vaccines against a virus. They can be given after infection to treat disease.

Vaccines, on the other hand, are given before infection and used to try to prevent disease. Once given, a vaccine will trigger your body's immune system to make antibodies, similar to if you were exposed to the virus naturally. This can give you protection (immunity) against a future infection if you're exposed to the virus again later.