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COVID-19 patients with no symptoms likely to stay that way: Japanese researchers

Jun 15, 2020 (Japan Times) - What are the odds COVID-19 patients with no symptoms could later develop them?

Quite slim, according to a recent study led by a group of researchers in Aichi Prefecture, who have discovered that asymptomatic coronavirus patients tend to recover within nine days of having their infections confirmed via polymerase chain reaction (PCR) tests.

The findings, involving a study on how the disease developed in 90 people without symptoms who contracted the disease aboard the Diamond Princess cruise ship, were published Friday in the New England Journal of Medicine and showed that only 11 people without symptoms would go on to develop them later.

“In this cohort, the majority of asymptomatic infected persons remained asymptomatic throughout the course of their infection,” a team led by Yohei Doi, a doctor and professor of the department of infectious diseases at Fujita Health University wrote in the report.

The results showed that nearly half of the patients were cleared of the virus within nine days after first testing positive for COVID-19, while 90 percent of people recovered within 15 days. The findings also showed that most patients were unlikely to recover within five days after the initial positive test.

Based on the findings, the health ministry on Friday revised its guidelines for hospitalization of COVID-19 patients. It is now advising that patients who test negative twice over six days after the initial positive test should be discharged.

Fujita Health University’s Okazaki Medical Center took in 128 people from the virus-hit Diamond Princess — 96 passengers who tested positive for the coronavirus but had no symptoms and 32 of their cabinmates who tested negative. All were between the ages of 9 and 77. In total, data on 90 patients without symptoms were available for analysis.

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