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If you've had COVID-19, are you immune to it?

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Health experts don't yet know whether we  become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.Thus far, there have been only a few incidents of confirmed re-infections. With two cases, it appears the patients were re-infected by the same strain, while the third was infected with a slightly different strain of the virus.

Other types of coronaviruses appear to cause some immunity. Studies show that people are protected against the coronaviruses that cause the common cold for up to a year after an infection. And our bodies have antibodies against the SARS coronavirus for up to 4 years.

Most people who've recovered from COVID-19 do make antibodies against the virus. But so far, there's no evidence that this will protect them against the virus if they're exposed to it again.

In South Korea, more than 160 people tested positive again after they had recovered from COVID-19. In China, 5%-10% of people tested positive again after they'd recovered, according to news reports. It's not clear whether:

  • These people got infected again
  • The virus reactivated in their bodies after being quiet for a while, or
  • The test results were flawed

SOURCES:

Children's Hospital of Philadelphia: "Types of Immunity."

FDA: "Coronavirus (COVID-19) Update: Serological Tests," "Coronavirus (COVID-19) Update: Serological Test Validation and Education Efforts."

Harvard Medical School: "If you've been exposed to the coronavirus."

Immunologic Research: "T cell-mediated immune response to respiratory coronaviruses."

Johns Hopkins Bloomberg School of Public Health: "What Is Herd Immunity and How Can We Achieve It With COVID-19?"

Johns Hopkins Center for Health Security: "Serology-based tests for COVID-19."

KidsHealth.org: "Immune System."

MD Anderson Cancer Center: "7 things to know about COVID-19 antibody testing."

Microbiology Society: "Antibody-antigen complex."

New England Journal of Medicine: "Asymptomatic Transmission, the Achilles' Heel of Current Strategies to Control Covid-19."

University of California San Francisco: "The Promise and Uncertainties of Antibody Testing for Coronavirus."

Vaccines.gov: "Vaccines Protect Your Community."

World Health Organization: "'Immunity passports' in the context of COVID-19."

Canadian Medical Association Journal:" COVID-19: Recent updates on the coronavirus pandemic."

National Institutes of Health: "NIH begins study to quantify undetected cases of coronavirus infection."

Reviewed by Brunilda Nazario on September 23, 2020

SOURCES:

Children's Hospital of Philadelphia: "Types of Immunity."

FDA: "Coronavirus (COVID-19) Update: Serological Tests," "Coronavirus (COVID-19) Update: Serological Test Validation and Education Efforts."

Harvard Medical School: "If you've been exposed to the coronavirus."

Immunologic Research: "T cell-mediated immune response to respiratory coronaviruses."

Johns Hopkins Bloomberg School of Public Health: "What Is Herd Immunity and How Can We Achieve It With COVID-19?"

Johns Hopkins Center for Health Security: "Serology-based tests for COVID-19."

KidsHealth.org: "Immune System."

MD Anderson Cancer Center: "7 things to know about COVID-19 antibody testing."

Microbiology Society: "Antibody-antigen complex."

New England Journal of Medicine: "Asymptomatic Transmission, the Achilles' Heel of Current Strategies to Control Covid-19."

University of California San Francisco: "The Promise and Uncertainties of Antibody Testing for Coronavirus."

Vaccines.gov: "Vaccines Protect Your Community."

World Health Organization: "'Immunity passports' in the context of COVID-19."

Canadian Medical Association Journal:" COVID-19: Recent updates on the coronavirus pandemic."

National Institutes of Health: "NIH begins study to quantify undetected cases of coronavirus infection."

Reviewed by Brunilda Nazario on September 23, 2020

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