According tomedia BGR, researchers recently found a COVID-19 patient, the infectious new coronavirus in the body for at least 70 days, during which no symptoms. The patient has chronic lymphocytic leukemia, which may explain why the immune system is unable to initiate an appropriate response to remove the virus. Immunosuppressive patients are at risk of contracting COVID-19 and may experience unique complications because they have a harder time fighting pathogens.
The researchers found that the patient tested positive for the new coronavirus for 105 days and remained contagious 70 days after the first positive test.
As ScienceDaily explains, PCR testing can detect the presence of SARS-CoV-2 RNA in a sample. But this RNA may not always be viable, especially in the last days of the COVID-19 routine. For the study, the researchers actually tested samples to see if the virus on the swabs could still infect lab-grown cells. And that’s how they found out that this particular patient was still contagious after 70 days.
“This suggests that it is highly likely that the infectious virus that the patient has shed can still establish a productive infection in the contact after transmission.” Scientists say.
What keeps the virus alive for so long is a condition that already exists in the host. The 71-year-old suffers from 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 immunological studies, are involved in the immune process. The woman was diagnosed with leukemia 10 years ago, and researchers believe patients with low immunity like her may be falling off longer than others.
ScienceAlert notes that about 3 million people in the U.S. suffer from diseases that damage their immune systems, making them more susceptible to infection. The list includes cancer patients receiving chemotherapy and transplant patients who may have taken immunosuppressants.
People with compromised immune systems may also develop more severe COVID-19 symptoms, but this did not happen in patients in this study. She tested positive for the first time since being admitted to hospital on 2 March with severe cancer-related anemia. She did not have COVID-19 symptoms. Doctors suspect the woman was infected at some point in February, when a major outbreak broke out at a rehabilitation facility.
Subsequently, the patient tested positive 13 times, but showed no symptoms. She received a plasma transfusion from other survivors and eventually cleared the virus in mid-June, although traces of RNA continued to appear in the sample for another 35 days. Given the possible date of infection, the person may even be infected for more than 70 days. According to the researchers, this is “the longest case of anyone infected with SARS-CoV-2 who remains asymptomatic.”
Although these cases may be rare, patients who have been infected for months without any symptoms may unknowingly transmit the virus to countless people.
This particular case study can be found in the journal Cell.