If you’ve had COVID-19, with or without symptoms, you may have questions
Reinfection with the virus that causes COVID-19 means a person was infected, recovered, and then later became infected again. After recovering from COVID-19, most individuals will have some protection from repeat infections. However, reinfections do occur after COVID-19. We are still learning more about these reinfections. Ongoing studies of COVID-19 are helping us understand:
- How often reinfections occur
- Who is at higher risk of reinfection
- How soon reinfections take place after a previous infection
- The severity (how serious the infection is) of reinfections compared with initial (the first) infection
- The risk of transmission to others after reinfection
After you have completed your isolation period, it is required that you continue to follow campus policies regarding masking.
Recommendations for masking for most indoor spaces on campus, including instructional spaces, will be aligned with the CDC’s COVID-19 community level for Washtenaw county.
Masks will remain required in patient care areas (e.g., Michigan Medicine, University Health Service, and the Dental School clinical areas) and at U-M COVID-19 testing sites as noted under the U-M Face Covering Policy.
People who have symptoms of COVID-19 should be tested for COVID-19 regardless of vaccination status or prior infection.
If you have had a COVID-19 infection within the past 90 days and you have new symptoms, it is advised that you test using an antigen test rather than a PCR test.
Point-of-care serial screening testing can provide rapid results and is critical to identifying people with COVID-19 who do not have symptoms and slowing the spread of SARS-CoV-2. This is especially important when the COVID-19 community level is high.
Positive test results using a viral test (antigen or NAAT) in people with signs or symptoms consistent with COVID-19 indicate that the person has COVID-19, independent of the vaccination status of the person. A negative test can either be followed by a 2nd antigen test (after 24 hours) or by a NAAT (PCR) test. For more information, see our at-home antigen test page.
Most people with COVID-19 have mild illness and can recover at home without medical care. For more information, see CDC’s COVID-19 quarantine and isolation guidance
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 your exercise intensity.
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 or serology tests look for antibodies in your blood that fight the virus that causes COVID-19.
- Antibodies are proteins created by your immune system that help you fight off infections. They are made after you have been infected or have been vaccinated against infection.
- Vaccination is a safe, effective way to teach your body to create antibodies.
- Antibodies can protect you from getting those infections for some period of time afterward. How long this protection lasts is different for each disease and each person.
- Antibody tests should generally not be used to diagnose a current infection with the virus that causes COVID-19. An antibody test may not show if you have a current infection because it can take 1-3 weeks after the infection for your body to make antibodies.
Effect of vaccination
- COVID-19 vaccines teach your body to produce antibodies to fight infection from the virus that causes COVID-19. If you get an antibody test after receiving a vaccine, you might test positive by some (but not all) antibody tests. This depends on which type of antibody the specific test detects.
- Antibody testing is not currently recommended to determine if you are immune to COVID-19 following COVID-19 vaccination. Antibody testing should also not be used to decide if someone needs to be vaccinated. The CDC provides more information on how antibody testing should be used and interpreted.
UHS can provide antibody testing, a blood test that can be performed in our laboratory. The testing available includes nucleocapsid and/or spike antibody testing.
U-M students, current UHS patients, and certain others are eligible. See Who Can Use UHS? for eligibility.
If you test positive
- A positive antibody test result shows you may have antibodies from a previous infection or from vaccination for the virus that causes COVID-19.
- Some antibodies made for the virus that causes COVID-19 provide protection from getting infected. The CDC is evaluating antibody protection and how long protection from antibodies might last. Cases of reinfection and infection after vaccination have been reported, but remain rare. Getting vaccinated, even if you have already had COVID-19, can help your body make more of these antibodies.
- You may test positive for antibodies even if you have never had symptoms of COVID-19 or have not yet received a COVID-19 vaccine. This can happen if you had an infection without symptoms, which is called an asymptomatic infection.
- Sometimes a person can test positive for SARS-CoV-2 antibodies when they do not actually have those specific antibodies. This is called a false positive.
- Talk with your healthcare professional about your test result and the type of test you took to understand what your result means. Your healthcare professional may suggest you take a second type of antibody test to see if the first test was accurate.
If you test negative
- You may not have COVID-19 antibodies. This could be because you have not had an infection with the virus that causes COVID-19 or have not received a COVID-19 vaccine.
- Antibody testing is not currently recommended to determine if you are immune to COVID-19 following COVID-19 vaccination.
- Some antibody tests will only detect antibodies from infection, not from vaccination with the virus that causes COVID-19.
- You could have a current infection, been recently infected, or been recently vaccinated. It typically takes 1-3 weeks after infection or vaccination for your body to make antibodies. If you are infected, you may get sick and spread the virus before you develop antibodies.
- Some people may take even longer to develop antibodies, and a small portion of people who are infected or vaccinated may never develop antibodies.
- Sometimes people test negative for SARS-CoV-2 antibodies when they have those specific antibodies. This is called a false negative.
- Talk with your healthcare professional about your test result and the type of test you took to understand what your result means.
If you have symptoms of COVID-19, you should get a viral test to detect a current infection, even if you were previously infected or vaccinated.
See also Antibodies and COVID-19 from the CDC.
Some people who have been infected with the virus that causes COVID-19 can experience long-term effects from their infection, known as post-COVID conditions (PCC) or long COVID.
People call post-COVID conditions by many names, including long COVID, long-haul COVID, post-acute COVID-19, post-acute sequelae of SARS CoV-2 infection (PASC), long-term effects of COVID, and chronic COVID.
- Post-COVID conditions can include a wide range of ongoing health problems; these conditions can last weeks, months, or years.
- Post-COVID conditions are found more often in people who had severe COVID-19 illness, but anyone who has been infected with the virus that causes COVID-19 can experience post-COVID conditions, even people who had mild illness or no symptoms from COVID-19.
- People who are not vaccinated against COVID-19 and become infected may also be at higher risk of developing post-COVID conditions compared to people who were vaccinated and had breakthrough infections.
- There is no single test for post-COVID conditions. While most people with post-COVID conditions have evidence of infection or COVID-19 illness, in some cases, a person with post-COVID conditions may not have tested positive for the virus or known they were infected.
- The CDC and its partners are working to understand more about who experiences post-COVID conditions and why, including whether groups disproportionately impacted by COVID-19 are at higher risk.
- The University of Michigan Health Pos-COVID-19 Clinic provides care to adult patients experiencing prolonged post-COVID symptoms.
- Long-COVID or Post-COVID Information from the CDC.