The real number of COVID-19 cases in the United States could be much higher than the official data, as the previous testing procedure was flawed, according to U.S. researchers and media reports.
Alexis C. Madrigal, a staff writer at U.S. magazine The Atlantic, said the official data were untrustworthy because the Centers for Disease Control and Prevention(CDC)'s testing procedures missed the bulk of the cases.
"They focused exclusively on travelers, rather than testing more broadly, because that seemed like the best way to catch cases entering the country," he wrote in an article published in the technology column of the magazine on Tuesday.
Until very recently, the CDC had insisted that only its test could be used, and only on patients who met specific criteria - those who had traveled to China within 14 days of developing symptoms or had contact with a known coronavirus case.
Trevor Bedford, an associate professor at the Fred Hutchinson Cancer Research Center and the University of Washington, warned that the disease had been circulating in Washington for six weeks -- but went undetected because of strict testing restrictions set by the CDC.
He made the conclusion after examining the genomes of two infections in the Washington state, the New York Times reported on Sunday.
If the virus has been spreading undetected in Washington since mid-January, that could mean that anywhere from 150 to 1,500 people may have it, with about 300 to 500 people being the most likely range, Mike Famulare, a principal research scientist at the Institute for Disease Modeling in Bellevue, Washington state told the New York Times.
The figure is a "best guess, with broad uncertainty," Famulare added.
As of Tuesday afternoon, the officially reported cases of COVID-19 in the United States stood at 129, according to the CDC.
To make things worse, part of CDC's testing kits were found to be defective. Although it developed the RT-PCR tools in early February, it turned out that some of them contained a faulty reagent, thus producing inconclusive results and further slowing down the testing efforts of local health departments.
"There have been blunders, and there could be an underlying catastrophe that we don't know about," said epidemiologist Michael Mina, who helps run a microbiology testing lab at Brigham and Women's Hospital.
Although the U.S. government has announced a dramatic expansion of testing, but experts said it would likely take weeks to put in place.
"(The pace of testing is) still low, and it will take weeks until we have anything like adequate testing capacity," said Marc Lipsitch, a professor of epidemiology at the Harvard T.H. Chan School of Public Health.