Clinical Public Health

Period. 14 – 21 July 2020
  • Rapid and non-invasive antibody diagnostics remain a holy grail in scaling up testing for COVID-19. Preliminary results are currently under peer review for the rapid finger prick antibody test, AbC-19 Lateral Flow, that claims to be 98.6% accurate. While these claims seem promising, the results have not been made public, with questions remaining on the sets of samples the study used or what the researchers mean by ‘accuracy’. Diagnostic tests are typically assessed by sensitivity (false negative) and specificity (false positive). The other outstanding issue with these types of tests, however, relate to uncertainties in the period of time after infection that IgG antibodies disappear from the blood. Since acuity of COVID-19 infection appears to be correlated with the intensity of the antibody response, it is plausible that the test could come back negative for those with low antibody levels in as little as three months (for reference, antibody levels for SARS were detectable for up to two years). A rapid antibody test would nonetheless be a valuable diagnostic tool for detecting positive cases, even if negative test results would require further investigation. It is also important to note that other human coronaviruses don’t confer lifelong immunity, while ongoing research is also examining the role of T-cell immunity.


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