University Health Service

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If you’ve had COVID-19, with or without symptoms, you may have questions.

After COVID-19 infection, will I be immune to it?

People who had COVID-19 may have some immunity against it for up to three months after infection.  Through time, immunity likely wanes.

Do I still need to practice prevention measures if I had COVID?

Yes, continue to wear a mask, practice social distancing, etc. Cases of reinfection of COVID-19 have been reported but are rare, so protect yourself. Preventive measures also protect others from infection.

If I have a new exposure or develop symptoms, do I need to test or quarantine?

For up to three months after your COVID infection:

  • If you have a new exposure and no symptoms, you do not need to quarantine or get tested. (Your test result may be positive from your previous infection.)
  • If you develop symptoms with no other known cause for those symptoms, you may need to be tested again or otherwise evaluated to look for alternative causes for your symptoms. Please consult a health care provider. U-M students can use UHS.

When can I resume exercise after COVID infection?

If you exercise moderately, say for recreation and general fitness, and if you had mild or moderate symptoms (no hospitalization, no significant cardiac symptoms), you can resume exercise at moderate intensity after all your symptoms have disappeared. Start slowly and gradually return to your previous level of activity. If you experience any new or recurring symptoms, reduce exercise.

If you exercise strenuously or are a competitive athlete, you should seek advice from a health care provider before returning to exercise, whether or not you experience symptoms.

Antibody testing

What is antibody testing for COVID-19?

Antibody testing can identify past COVID-19 infection. It can detect antibodies called IgM or IgG in blood within 2-3 weeks after COVID symptoms start or COVID is diagnosed. The immune system produces these antibodies in response to COVID-19 infection. The duration and relative amount of antibodies remaining in the blood following COVID-19 is unknown.

How can I get antibody testing?

UHS can provide antibody testing, a blood test that can be performed in our laboratory.

U-M students, current UHS patients and certain others are eligible. See Who Can Use UHS? for eligibility.

If you would like to get an antibody test, begin the process by completing our Online Assessment for Upper Respiratory Infection and COVID-19

What do antibody test results mean?

A positive antibody test result means that IgM or IgG antibodies were detected, which indicates likely past infection with COVID-19.

A negative antibody test result means that IgM or IgG antibodies were NOT detected, which indicates:

  • Any antibody response from a prior infection has waned
  • Testing may have occurred before antibody response OR
  • You were not infected previously with COVID-19 OR

Regardless of test results, you should continue to practice social distancing, wear masks, and frequently wash hands, because currently there is no conclusive evidence that antibodies provide protection against future infections.

See also Test for Past Infection from the CDC.

Plasma donation

What is plasma donation?

People who have fully recovered from COVID-19 have antibodies in their plasma that can attack the virus. Plasma is the liquid portion of your blood. Convalescent plasma is the term used for plasma that is taken from the blood of a person who has recovered from a disease, then transfused into a patient still battling that disease.

Convalescent plasma is being evaluated as a treatment for patients with serious or immediately life-threatening COVID-19 infections, or those considered to be at high risk of severe or life-threatening disease. Decisions about who is eligible to receive convalescent plasma therapy are made by health care providers.

What is the process to collect plasma?

During a plasma donation, blood is drawn from an arm to a machine that collects your plasma and then safely and comfortably returns your red cells back to you, along with some saline. Because of this process, donating plasma does take longer than a regular whole blood donation.

Where can I learn more about plasma donation or other donation?

  • See American Red Cross for information about whether and how you can donate plasma. You would need to be symptom-free, fully recovered, feel well, and meet age and weight requirements.
  • U-M researchers are developing a biorepository focused on COVID-19 research. Learn more about donating to this project.

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