In what appears to be a first, disease trackers in Singapore have used an experimental antibody test for COVID-19 to confirm that a suspected patient was infected with the coronavirus. The patient was one of two people who together formed a missing link between two clusters of cases that each occurred in a Singaporean church.
Researchers around the world are racing to develop antibody tests, also called serological tests, that can confirm whether someone was infected even after their immune system has cleared the virus that causes COVID-19. The group that developed the test, at Duke-NUS Medical School in Singapore, is among the front-runners, although its assay has to be validated before it is taken into production and deployed widely.
Current tests for SARS-CoV-2, the virus that causes COVID-19, look for genetic material of the virus, for instance in saliva or nasal, oral, or anal swabs, using the polymerase chain reaction (PCR). They have one huge drawback: They only give a positive result when the virus is still present. The tests can’t identify people who went through an infection, recovered, and cleared the virus from their bodies.