Tuesday 21 April 2020

New Reports Suggest Many Have Had Coronavirus With No Symptoms, But Methodology Called Into Question

In a country of 328 million, there have been just 3.9 million tests performed for COVID-19, Johns Hopkins Center for Systems Science and Engineering.
That means less than 1.2% of Americans have been tested. Of those who have, nearly 762,000 have tested positive. That’s just 19.5% of the number tested.
Now, a slew of new reports are appearing that say that many Americans have already had the coronavirus but showed no symptoms at all.
“Based on known cases, health officials have said the virus usually causes mild or moderate flu-like illness,” The Associated Press reported Monday. “Now evidence is growing that a substantial number of people may have no symptoms at all.”
In the last week, reports of silent infections have come from a homeless shelter in Boston, a U.S. Navy aircraft carrier, pregnant women at a New York hospital, several European countries and California.
The head of the U.S. Centers for Disease Control and Prevention says 25% of infected people might not have symptoms. The vice chairman of the Joint Chiefs of Staff, Gen. John Hyten, thinks it may be as high as 60% to 70% among military personnel.
None of these numbers can be fully trusted because they’re based on flawed and inadequate testing, said Dr. Michael Mina of Harvard’s School of Public Health. Collectively, though, they suggest “we have just been off the mark by huge, huge numbers” for estimating total infections, he said.
A New York hospital that tested all pregnant women there to deliver their children over a two-week period found that 14% actually tested positive but had no symptoms of coronavirus infection.
In a random study of 200 residents on a single street in Chelsea, Massachusetts, about a third of participants  tested positive for coronavirus, according to researchers.
That study, too, was not scientific, but “still, it’s kind of sobering that 30 percent of a random group of 200 people that are showing no symptoms are, in fact, infected,” Thomas Ambrosino, Chelsea’s city manager, told the Boston Globe.
Another study by Stanford University found the number of people infected with coronavirus  could be tens of times higher than previously thought. The study “tested samples from 3,330 people in Santa Clara county and found the virus was 50 to 85 times more common than official figures indicated,” The Guardian reported.
“In a startling finding, new Stanford research reveals between 48,000 and 81,000 people in Santa Clara County alone may already have been infected by the coronavirus by early April — that’s 50 to 85 times more than the number of official cases at that date,” The Mercury News reported.
But that study has not yet been peer reviewed, and another report from the Mercury News called into questions Stanford’s findings.
Critics claim the study’s methodology is dangerously flawed and question the political motives of the Stanford-led team. Others have pointed to the study as proof that COVID-19 is merely a partisan-driven flu hoax, as protests broke out this weekend in parts of the country over frustrations with the shutdowns.
The AP also noted that some of the new reports have “flawed methods.”
These studies used tests that look for bits of the virus from throat and nose swabs, which can miss cases. Someone can test negative one day if there’s not much virus to detect and then positive the next.
Symptoms also may not appear when someone is tested but turn up later. One Japanese study found more than half of those who had no symptoms when they tested positive later felt sick.
But the AP noted optimistically: “Better answers may come from newer tests that check blood for antibodies, substances the immune system makes to fight the virus.”
The wire service then added a pessimistic note: “But the accuracy of these, too, is still to be determined.”

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