Convalescent Plasma

What is convalescent plasma?

Convalescent plasma therapy is a transfusion of plasma (the liquid part of your blood) to help you fight an infectious disease. The plasma comes from someone who recovered from the same illness. While their body fought the disease, it made antibodies. These antibodies are transferred to you through their plasma, which allows your immune system to recognize and attack the infection.

What conditions does convalescent plasma treat?

Healthcare providers usually use convalescent plasma to treat new viral infections that can cause severe illness. Convalescent plasma can help prevent life-threatening illness when other treatments or vaccines haven’t been developed yet.

Providers have used convalescent plasma to treat:

• COVID-19.
• Viral hemorrhagic fevers, like Ebola.
• SARS (severe acute respiratory syndrome).
• Bird flu (avian influenza).
• H1N1 (swine flu).

How does convalescent plasma work?

Convalescent plasma therapy works by providing passive immunity. Passive immunity is like borrowing someone else’s immune defenses (though you can’t give them back).

The first time your body encounters a germ (pathogen) — before you’ve been infected with it or vaccinated against it — you don’t have the ability to recognize an infection and quickly fight it off (adaptive immunity). It can take your immune system as long as two to three weeks to develop the antibodies needed to fight a specific infection.

Convalescent plasma comes from someone who’s already been infected with and recovered from (convalesced) the same illness. Their plasma contains antibodies that they developed while fighting the infection. Given early enough, this can help your body fight the infection while your immune system has time to develop its own response.

What happens before convalescent plasma transfusion?

Before you receive convalescent plasma, your healthcare provider will check your medical history, blood type and overall health. Donors need to have made a full recovery from the illness and have a high level of antibodies in their blood to donate convalescent plasma.

What happens during a convalescent plasma transfusion?

During a convalescent plasma transfusion:

1. You’ll lie in a bed or sit in a chair.
2. A healthcare provider will clean and disinfect an area of your arm.
3. They’ll place a needle into a vein in your arm and attach an IV (intravenous) line.
4. Over an hour or more, the plasma will travel from its bag, through a tube and into the vein in your arm.
5. Your provider will remove the needle and have you put pressure on the site with gauze until it’s stopped bleeding. They’ll cover it with a bandage.
6. After the transfusion, your provider will monitor you for side effects.

How long does a plasma transfusion take?

Plasma transfusions can take one to four hours.

What are the potential advantages of convalescent plasma?

Advantages of convalescent plasma therapy include:

• It might reduce your likelihood of severe illness and complications.
• It can give providers a treatment option before vaccines, antivirals and other treatments are available for new illnesses.
• It can provide antibodies against the most recent variants (types) of a particular virus.
• It can provide antibodies to people who have a weakened immune system or who haven’t made antibodies after getting vaccinated.
• It’s generally safe and low risk.

How successful is convalescent plasma?

The effectiveness of convalescent plasma depends on many factors, including what it’s treating and how soon you’re treated. For instance, studies suggest that people treated with convalescent plasma within the first few days of COVID-19 symptoms are 30% to 50% less likely to be hospitalized with severe illness.

But other studies don’t show a significant difference in mortality (death) rates between people who received convalescent plasma for COVID-19 and those who didn’t. This might be because many studies looked at people who were already severely ill before receiving treatment, past the point where it could help.

Studies done during Ebola outbreaks haven’t shown a significant difference in survival rates for people who received convalescent plasma versus those who didn’t.

Is convalescent plasma therapy safe?

Blood and plasma transfusions are generally safe, thanks to testing and screening of donors and their blood. While complications are rare, convalescent plasma therapy risks include:

• Fever.
• Allergic reactions.
• Infections at the IV site.
• Chronic infections such as HIV, hepatitis B and hepatitis C (these are extremely rare).

How long will it take for me to feel better?

You likely won’t feel better right away after treatment with convalescent plasma. The goal of convalescent plasma therapy is often to prevent life-threatening illness. It will still take some time to recover from being sick.

When should I call my healthcare provider?

Contact your healthcare provider if you have any questions about your treatment or if you think you’re experiencing side effects. Your provider can also tell you the kinds of symptoms or side effects to look out for and when to get medical attention.

Is convalescent plasma therapy still used to treat COVID-19?

In some cases. For instance, the U.S. Food and Drug Administration (FDA) currently only approves the use of convalescent plasma to treat people with compromised immune systems who have COVID-19. The plasma must have high levels (titer) of antibodies.

For most people, getting vaccinated and taking antivirals if your provider recommends them is the best way to prevent severe illness from COVID-19.

A note from Cleveland Clinic

Using someone else’s antibodies to fight an infection is a bit more complicated than borrowing a trowel to clear weeds out of your garden. But convalescent plasma gives healthcare providers an additional treatment tool, often when other options aren’t yet available. It might reduce your risk of serious illness by teaching your immune system to recognize and fight invaders it’s never seen before.

Talk to your healthcare provider if you have a compromised immune system and wonder if convalescent plasma could be an option if you get sick. They can discuss with you what treatment options are available and could be right for you.