Scientific Brief released by the World Health Organisation confirms that the antibodies test for COVID-19 is unreliable which refutes Melham's claim.
But according to the Centers for Disease Control and Prevention, the first confirmed corona case emerged in Washington State of the U.S. on 21 January 2020.
Meanwhile, the World Health Organization has said that laboratory tests that detect antibodies to SARS-CoV-2 in people, including rapid immunodiagnostic tests, need further validation to determine their accuracy and reliability and may falsely label people as infected with the novel coronavirus. These tests also need to accurately distinguish between past infections from SARS-CoV-2 and those caused by the known set of six human coronaviruses. People infected by any one of these viruses may produce antibodies that cross-react with antibodies produced in response to infection with SARS-CoV-2. Further, experts have said that an antibody test result isn’t black and white for individuals.
Therefore, there is no evidence to support the New Jersey Mayor's statement that he has tested positive for COVID-19 antibody test, and he was infected by COVID-19 in November 2019. Coronavirus antibody tests are not very accurate and reliable.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.