A new study suggests more people have been infected with COVID-19 than has been officially reported. What do we need to know about this research?
A preliminary study (opens external site), posted by researchers at the Australian National University and elsewhere, estimated 71,000 Australians had been infected with COVID-19 by mid-July. This is 60,000 more than the official number of cases diagnosed.
The study tested 2,991 elective surgery patients in ten hospitals across four states, to see whether they had antibodies against SARS-CoV-2, the virus that causes COVID-19.
The study found 41 positive patients (1.4%), but then adjusted for the false positives that would arise due to the imperfect specificity of the antibody test, which the researchers estimate would produce 11 false positives for every 1,000 tests. This yielded an estimated prevalence of 0.28% — or eight “true” positives from the 2,991 people sampled.
The researchers then extrapolated this estimate, including its uncertainty parameters, to the Australian population as a whole. They ultimately concluded the number of Australians with SARS-CoV-2 antibodies — and who have therefore presumably been infected with COVID-19 — is somewhere between zero and 181,050, and most likely about 71,000.
This study presents questions of whether we should alter our view on how best to contain the spread of COVID-19, and whether there are any limitations to the study that should be noted.
When interpreting the results there are four key components to consider: false positives, sample size, testing method and extrapolation.
Read about each component and access the full story on UTS News: Has Australia really had 60,000 undiagnosed COVID-19 cases?
This article is republished from The Conversation under a Creative Commons license. Read the original article [opens external site].
Byline
Andrew Hayen, University of Technology Sydney and Gregory Dore, UNSW