BEIJING: China reported 10 new COVID-19 cases as of the end of Wednesday, down from 30 a day earlier, even as concerns rose about the accuracy of tests.
The National Health Commission said on Thursday (Apr 23) six of the new COVID-19 cases confirmed on Wednesday were imported, down from 23 a day earlier.
The number of new asymptomatic patients, or people who are infected but do not show symptoms, also declined to 27 from 42 a day earlier.
The total number of confirmed coronavirus cases for mainland China now stands at 82,798.
No new COVID-19 deaths were reported, leaving the toll unchanged at 4,632.
PROBLEMS WITH COVID-19 TESTS
The declining numbers come amid rising concerns over the accuracy of coronavirus tests.
One such example is trader He Ximing in Wuhan city, who says he has no idea how or where he caught the coronavirus or why repeated nucleic acid tests showed he didn’t have it.
He was not a coronavirus patient, doctors told him, even though he had been having difficulty breathing with what he described as smothering chest congestion from early February.
But his condition worried the authorities enough to get him sent to a quarantine centre.
Still, he did not challenge the three negative tests at the time. After all, his wife did not fall sick.
But he could not shake off the nagging suspicion that he had the coronavirus and in late March went to a hospital in Wuhan for more tests, including one for antibodies.
This time he tested positive.
“I didn’t expect it,” the 52-year-old vegetable seller said as he showed Reuters a copy of his test results – positive for antibodies showing exposure to the coronavirus.
Finally, at least, he had an explanation for why he felt so terrible. “I felt like I was dying. You can’t imagine how it feels.”
Wuhan, where the new coronavirus emerged late last year, accounts for the majority of China’s cases.
Nucleic acid testing, on samples swabbed from the back of a patient’s throat or respiratory tract, for the virus’ genome, is the main way cases are detected.
The test is not easy to administer and, experts say, and mistakes do happen, such as if too small a sample is taken or if the swab misses a virus-hit spot.
“The limitations of these tests need to be recognised, and the need to run regular tests if we want assurance that someone is truly negative, and that they remain so over a period of time,” said Andrew Preston, a lecturer in microbial pathogenesis at the University of Bath.
There is little consensus on what proportion of nucleic acid tests yield false negatives.
A survey by Chinese doctors in February looking at samples from 213 patients suggested a false-negative rate of about 30 per cent.
The media has also reported cases of people testing negative repeatedly before finally getting a positive result.
In February, the People’s Daily newspaper reported on a woman who had fallen ill with pneumonia but tested negative for the coronavirus four times.
A fifth test was positive.