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The Daily Insight

What are monoclonal antibodies and how do they work

Author

Andrew Walker

Updated on April 19, 2026

Monoclonal antibodies are laboratory-produced molecules that act as substitute antibodies that can restore, enhance or mimic the immune system’s attack on cells. Monoclonal antibodies for COVID-19 may block the virus that causes COVID-19 from attaching to human cells, making it more difficult for the virus to reproduce and cause harm. Monoclonal antibodies may also neutralize a virus.

How many types of monoclonal antibody COVID-19 treatments are there in the US?

In the United States, there are three anti-SARS-CoV-2 monoclonal antibody treatments with FDA Emergency Use Authorization (EUA) for the treatment of COVID-19: bamlanivimab plus etesevimab, casirivimab plus imdevimab,, and sotrovimab.

How do monoclonal antibodies work against COVID-19?

Monoclonal antibodies for COVID-19 may block the virus that causes COVID-19 from attaching to human cells, making it more difficult for the virus to reproduce and cause harm. Monoclonal antibodies may also neutralize a virus.

How long does it take for the body to produce antibodies against COVID-19?

Antibodies can take days or weeks to develop in the body following exposure to a SARS-CoV-2 (COVID-19) infection and it is unknown how long they stay in the blood.

For which COVID-19 patients has been approved Remdesivir?

On October 22, 2020, the FDA approved the antiviral drug Veklury (remdesivir) for use in adults and pediatric patients (12 years of age and older and weighing at least 40 kg) for the treatment of COVID-19 requiring hospitalization.

What medication is not recommended before vaccinations for COVID-19?

It is not recommended you take over-the-counter medicine – such as ibuprofen, aspirin, or acetaminophen – before vaccination for the purpose of trying to prevent vaccine-related side effects. It is not known how these medications might affect how well the vaccine works.

Can I get the COVID-19 vaccine if I was treated with monoclonal antibodies or convalescent plasma?

If you were treated for COVID-19 symptoms with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting a COVID-19 vaccine.

How long does it take to produce antibody after COVID-19 vaccine?

In addition, it takes around two weeks for the body to generate antibodies after COVID-19 vaccination, so even tests to detect the “right” antibody could be negative in the first few weeks after vaccination.

What does a negative antibody test for COVID-19 mean?

A negative result on a SARS-CoV-2 antibody test means antibodies to the virus were not detected in your sample. It could mean: You have not been infected with COVID-19 previously. You had COVID-19 in the past but you did not develop or have not yet developed detectable antibodies.

Does an antibody test diagnose an active COVID-19?

Antibodies can take several days or weeks to develop after you have an infection and may stay in your blood for several weeks after recovery. Because of this, antibody tests should not be used to diagnose an active coronavirus infection.

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Are antibiotics effective in preventing or treating COVID-19?

Antibiotics do not work against viruses; they only work on bacterial infections. Antibiotics do not prevent or treat COVID-19, because COVID-19 is caused by a virus, not bacteria. Some patients with COVID-19 may also develop a bacterial infection, such as pneumonia.

How can convalescent plasma be used to treat COVID-19?

The blood from people who recover from COVID-19 contains substances called antibodies, which are capable of fighting the virus that causes the illness. For some other diseases caused by respiratory viruses, giving people the liquid portion of blood that contains these antibodies, called plasma, obtained from those who have recovered from the virus, may lead to more rapid improvement of the disease. Patients with COVID-19 may improve faster if they receive plasma from those who have recovered from COVID-19, because it may have the ability to fight the virus that causes COVID-19.

Is Remdesivir approved in Europe for treatment of COVID-19?

Since July 2020, remdesivir has been conditionally approved in Europe for the treatment of coronavirus disease (COVID-19) in adults and adolescents aged 12 years and older with pneumonia who require supplemental oxygen but no invasive ventilation.

How does Remdesivir injection work to treat COVID-19?

Remdesivir is in a class of medications called antivirals. It works by stopping the virus from spreading in the body.

Should you get the Covid vaccine if you have an autoimmune disease?

The American College of Rheumatology COVID-19 Vaccine Clinical Guidance recommends that people with autoimmune and inflammatory rheumatic disease (which includes lupus) get the vaccine unless they have an allergy to an ingredient in the vaccine.

Can I get the COVID-19 vaccine if I have an underlying condition?

People with underlying medical conditions can receive a COVID-19 vaccine as long as they have not had an immediate or severe allergic reaction to a COVID-19 vaccine or to any of the ingredients in the vaccine. Learn more about vaccination considerations for people with underlying medical conditions. Vaccination is an important consideration for adults of any age with certain underlying medical conditions because they are at increased risk for severe illness from COVID-19.

How long does it take for the COVID-19 vaccine to take effect?

• It typically takes two weeks after you are fully vaccinated for the body to build protection (immunity) against the virus that causes COVID-19. If you are not vaccinated, find a vaccine. Keep taking all precautions until you are fully vaccinated.

How does the COVID-19 vaccine boost your immune system?

Vaccines work by stimulating your immune system to produce antibodies, exactly like it would if you were exposed to the disease. After getting vaccinated, you develop immunity to that disease, without having to get the disease first.

Is it normal to feel sick after having the COVID-19 vaccine?

It is normal to feel sick after getting a COVID-19 vaccine.

What does a positive COVID-19 antibody test result mean?

A positive result means the test did detect antibodies to the virus that causes COVID-19, and it is possible that you had a recent or prior COVID-19 infection and you have developed an adaptive immune response to the virus.

Can you have a negative antibody test for COVID-19 after vaccine?

The authorized vaccines for prevention of COVID-19 induce antibodies to specific viral protein targets; post-vaccination antibody test results will be negative in individuals without a history of previous natural infection if the test used does not detect the type of antibodies induced by the vaccine.

What causes false negatives in COVID-19 antibody tests?

Having an antibody test too early can lead to false negative results. That’s because it takes a week or two after infection for your immune system to produce antibodies. The reported rate of false negatives is 20%.

What is the COVID-19 antibody test?

An antibody test looks for antibodies that are made by the immune system in response to a threat, such as a specific virus. Antibodies can help fight infections. Antibodies can take several days or weeks to develop after you have an infection and may stay in your blood for several weeks after recovery. Because of this, antibody tests should not be used to diagnose an active coronavirus infection. At this time, researchers do not know if the presence of antibodies means that you are immune to the coronavirus in the future.

Are there different types of COVID-19 diagnostic tests?

There are 2 different types of COVID-19 diagnostic tests — molecular tests and antigen tests. Molecular tests detect the virus that causes COVID-19, SARS-CoV-2. Antigen tests detect specific proteins made by the virus.