Levine offers caveats on individual antibody testing

    Pennsylvania Secretary of Health Dr. Rachel Levine. Source: Pennsylvania Department of Health.

    This story was updated at 4:33 p.m. on Tuesday, 4/29/20 with additional comment from Penn State University.

    A positive antibody test for COVID-19 does not mean that an individual is immune to the virus, Health Secretary Dr. Rachel Levine cautioned Tuesday during her daily briefing.

    “How accurate the test is varies, and we do not know how protective those antibodies will be, and how long lived they will be,” Levine said.

    Antibody, or serology, testing looks for the presence of proteins that only appear in the blood of someone who has recovered from a specific disease.

    The tests are commonly known as “immunity tests,” but Levine said that they have limited use for individual health care.

    She did not advise Pennsylvanians against taking the test, but said that the a takeaway from a positive antibody test could be that an individual once had COVID-19.

    Subsequent studies are needed, Levine said, to determine if the tests had a use outside of helping public health officials track the diseases spread.

    Levine isn’t alone among health professionals in her assessment. 

    In an April 24 statement, the World Health Organization said “there is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.”

    Ping Du, an associate professor of public health at Penn State University, agreed, saying in an email that “it is too early to say that a positive antibody result would mean infection or protection” from COVID-19.

    She also pointed out that no tests have been fully approved by the federal government for doctor’s use, and have only been granted approval approval for emergency use.

    Levine’s statement comes after a Pennsylvania House panel advanced legislation to allow county health departments to begin serology testing programs.

    The legislation, sponsored by Rep. John Lawrence, R-Chester, was inspired by an effort in Chester County to use test kits from a local firm to check health care workers and first responders for antibodies.

    The state would provide a legal umbrella for the testing, but counties would pay for the testing, and must report all data to the state.