USA COVID-19 infection rates ‘much higher than tests show’
Doctors in the US and China have warned that coronavirus infection rates are likely to be wildly higher than the reported figures because of faulty testing.
And the situation is probably the same in Australia.
Infection rates could in fact be more than 30 per cent higher than official reporting figures.
Dr Harlan Krumholz, professor of medicine at Yale and director of the Yale New Haven Hospital Center for Outcomes Research and Evaluation, says the number of "false-negative" test results is frighteningly high.
"False-negative test results - tests that indicate you are not infected, when you are - seem to be uncomfortably common," he told the New York Times.
"Increasingly, and disturbingly, I hear a growing number of anecdotal stories from my fellow doctors of patients testing negative for coronavirus and then testing positive - or people who are almost certainly infected who are testing negative.
"Unfortunately, we have very little public data on the false-negative rate for these tests in clinical practice.
"Research coming out of China indicates that the false-negative rate may be around 30 per cent. Some of my colleagues, experts in laboratory medicine, express concerns the false-negative rate in this country could be even higher."
He said people with symptoms should assume they have the virus - even if the test comes back negative.
"Even with more testing, we are likely to be underestimating the spread of the virus. For now, we should assume that anyone could be carrying the virus. If you have had likely exposures and symptoms suggest COVID-19 infection, you probably have it - even if your test is negative. "
A family doctor in New York told News Corp Australia that it was "common knowledge" in the medical community that the tests were coming back with at least 30 per cent "false-negative" fail rates.
"Even if you get a negative result, if you have the symptoms then you need to assume you have the virus and act accordingly," the doctor said.
Dr Krumholz said people across the world with signs and symptoms of COVID-19 are testing negative and wondering what it means.
"They are not showing up in the statistics, and they are left in limbo about what to do next.
"The problem may be with the test. Current coronavirus tests may have a particularly high rate of missing infections.
"From a technical standpoint, under ideal conditions, these tests can detect small amounts of viral RNA (ribonucleic acid, which causes Ebola, SARS, COVID-19 - even the common cold).
"In the real world, though, the experience can be quite different, and the virus can be missed. "The best the Centers for Disease Control and Prevention can say is that if you test negative, 'you probably were not infected at the time your specimen was collected.' The key word there is 'probably'."
Dr Krumholz said the uncomfortable and invasive nature of the test may be part of the problem.
"There are many reasons a test would be falsely negative under real-life conditions. Perhaps the sampling is inadequate. A common technique requires the collection of nasal secretions far back in the nose - and then rotating the swab several times. That is not an easy procedure to perform or for patients to tolerate."
Originally published as COVID-19 infection rates 'much higher than tests show'