Two German citizens who looked healthy when they were evacuated from Wuhan, China in early February, were in fact infected with the coronavirus that causes COVID-19 and might have been able to spread it to others, according to one medical report released Tuesday.
The findings, published in the New England Journal of Medicine, highlight the limitations of health checks implemented around the world in hopes of containing the new virus.
Health officials began tracking travelers from China in mid-January, a few weeks after the outbreak began. Those arriving at US airports, for example, are checked for signs of fever, cough or difficulty breathing to determine whether they need further evaluation at a medical center.
The two Germans were part of a group of 126 people who flew from Wuhan, the epicenter of the outbreak, to Frankfurt, Germany, on February 1.
Six of the passengers were isolated during the flight because they had symptoms consistent with coronavirus infection. Two other passengers were relatives of them who joined them in isolation, and two others were separated because they came into contact with someone who had tested positive for the virus.
Upon arrival in Germany, these 10 passengers were sent to the University Hospital in Frankfurt. Swab and sputum samples were tested for genetic compatibility with the virus RT-PCR assay sanctioned by the World Health Organization. In the 10 cases, the test results were negative.
The other 116 passengers were assessed by medical personnel at Frankfurt airport. The travelers' noses and throats were examined and their temperatures were measured. They were also asked about a number of symptoms, including muscle pain, cough, fatigue and diarrhea.
One passenger had a 101-degree fever and was taken to the same hospital as the others. Later, that person also tested negative for the coronavirus.
The remaining 115 passengers were transferred to military quarters in Germersheim for 14 days in quarantine. Although they showed no signs of illness, a test was offered to see if they were infected. All but one agreed to do the RT-PCR assay.
Two of those 114 travelers were infected, the results revealed. Employees repeated the tests and obtained the same results. The diagnosis was also confirmed with a couple of commercial tests.
Not only were the two travelers infected, but the way their samples grew in laboratory dishes indicated that they had the potential to infect others, according to the report.
"We found that the shedding of potentially infectious viruses can occur in people without a fever and with no signs or only small signs of infection," wrote the team led by Dr. Sebastian Hoehl of the University Hospital in Frankfurt.
That is the bad news. The good news is that none of the travelers got very sick. They were admitted to the hospital and evaluated thoroughly, but all the doctors showed up was "a mild rash" and a little sore throat in one of them.
A week after admission, the two patients were well and without a fever, the doctors wrote.
On Tuesday, more than 73,000 cases of COVID-19 have been confirmed worldwide, and 1,875 people died. There were 16 confirmed cases and no deaths in Germany,