What to expect from monoclonal antibody treatment

There are two ways to administer a monoclonal antibody treatment. Both use needles and must be given by a trained medical professional. One is given by infusion into a vein, the other is given subcutaneously under the skin. Your healthcare provider or person giving the treatment will explain which type you are getting.

Infusion (In your vein)

You will have to go to an infusion center with specially trained staff to receive monoclonal antibodies as an infusion.


It will take 20 - 50 minutes, and possibly longer to finish the infusion. You will be asked to wait another hour after the infusion to make sure you don’t have serious side effects.

Subcutaneous (Under your skin)

If you receive monoclonal antibody treatment subcutaneously, you will get four shots with a short needle inserted under your skin in four separate places on your body. These usually include the back of the arms, the stomach and/or the thighs. Receiving all four shots takes about 1-3 minutes. You will be asked to wait an hour after your shots to make sure you don’t have serious side effects.

Side effects

With either treatment, you might have some discomfort at the injection site. This is common and should go away in a few days. 


Some people may experience a mild reaction including:

  • Brief pain
  • Mild bleeding
  • Bruising
  • Soreness
  • Swelling 

These are similar to what you may experience when getting other medicines by injection, like the COVID-19 vaccine or a flu shot. These may last for a few days. 


If you notice changes such as pain, redness, drainage, numbness, tingling, or other concerning symptoms near your injection site, call your healthcare provider.


Rare allergic reaction 

It is rare, but some people can have a severe allergic reaction to monoclonal antibody treatment. Everyone is asked to wait for at least one hour after treatment to make sure there is no serious allergic reaction and so help can be given right away if needed.


Other serious reactions

A very small number of people may experience a rare, but serious reaction to the treatment. Talk to your healthcare provider or seek medical care if you have any of these more serious symptoms in the days after your treatment:

  • Upset stomach (nausea, vomiting, or diarrhea)
  • Itching, swelling, rash, or hives
  • Dizziness or low blood pressure
  • Changes in your heartbeat
  • Any new or worsening symptoms
  • Difficulty breathing
  • Weakness
  • Confusion

What to expect after treatment?

After your treatment you should go home, rest and take care of your COVID-19 symptoms if you have them. If you have discomfort where you got the injections, you can use a cold compress the day of your treatment. After that, warmth (like a heating pad) can help heal any bruising. 


Most people will not need any additional follow up treatments. Your doctor will talk to you if they think you should get additional treatment.


You may begin to feel your COVID-19 symptoms improve quickly, or it may still take a while before you begin to feel better. In some cases, you may experience worsening COVID-19 symptoms. You should seek medical attention right away if your symptoms are serious, including: 

  • Trouble breathing
  • Persistent pain or pressure in the chest
  • New confusion
  • Inability to wake up or stay awake
  • Pale, gray, or blue-colored skin, lips, or nail beds, depending on skin tone. 

If you are unvaccinated, you should wait 90 days after your treatment to get the vaccine.

Who to call with questions?

If you have questions or concerns about your treatment, call your healthcare provider or the clinic where you received your treatment.