According to foreign media BGR, researchers recently discovered a COVID-19 patient. The infectious new coronavirus lasted for at least 70 days, and there were no symptoms during this period. This patient has chronic lymphocytic leukemia, which may explain why the immune system cannot initiate the appropriate response to clear the virus. Immunosuppressed patients are at risk of contracting COVID-19 and may experience unique complications because they have a more difficult time to fight the pathogen.
Researchers found that the patient tested positive for the new coronavirus for up to 105 days and was still contagious 70 days after the first positive test.
As ScienceDaily explains, PCR tests can detect the presence of SARS-CoV-2 RNA in the sample. But this RNA may not always be alive, especially collected in the last few days of a routine COVID-19 treatment. For the study, the researchers actually tested the samples to see if the virus on the swab can still infect lab-grown cells. And this is how they discovered that this particular patient was still contagious after 70 days.
"This shows that it is very likely that the infectious virus that the patient has shed can still establish a productive infection in the contact after it has spread," the scientists said. What is
? It is an existing disease in the host. The 71-year-old patient has chronic lymphocytic leukemia. It was a slow-moving white blood cell cancer that affected her immune response. White blood cells, like T cells mentioned in a large number of COVID-19 immune studies, are involved in the immune process. The woman was diagnosed with leukemia 10 years ago, and researchers believe that immunity-deficient patients like her may shed longer than others.
ScienceAlert points out that about 3 million people in the United States suffer from diseases that damage the immune system, making them more susceptible to infection. The list includes cancer patients receiving chemotherapy and transplant patients who may take the immunosuppressant .
People with damaged immune systems may also experience more severe symptoms of COVID-19, but this did not occur in patients in this study. She tested positive for the first time after being admitted to the hospital on March 2 for severe cancer-related anemia. She has no symptoms of COVID-19. Doctors suspect the woman was infected at some point in February when a major outbreak at a rehabilitation facility where she worked.
Then, the patient tested positive for 13 more times, but no symptoms appeared. She received plasma transfusions from other survivors and eventually cleared the virus in mid-June, although RNA traces continued to appear in the sample for another 35 days. Considering the possible date of infection, the person may have an infection time of more than 70 days. According to the researchers, this is "the longest case for anyone to remain asymptomatic by SARS-CoV-2 infection."
Although these cases may be rare, those who have been infected for months without any symptoms may unconsciously pass the virus to countless people.
This special case study can be seen in the journal Cell.
