Asymptomatic US woman remained infected with Covid-19 for at least 105 days, finds study

A woman in Kirkland Washington was infected with Covid-19 for at least 105 days and remained infectious for at least 70 of those days, according to a recent study published in the journal Cell .

The woman who as a leukaemia patient had a low antibody count. She had asymptomatic the entire time that she was infected with the virus, according to the study.

Senior author Vincent Munster, a virologist at the National Institute of Allergy and Infectious Diseases was contacted by infectious disease specialist Francis Riedo, a study co-author in April about a patient in Kirkland, Washington, who had been infected very early in the Covid-19 pandemic, according to an official release. She had been a resident of a rehabilitation facility experiencing a large outbreak.

The patient, a 71-year-old woman had tested positive numerous times through PCR tests over a period of weeks.

The woman was a high-risk patient as she was immuno-compromised due to chronic lymphocytic leukaemia and acquired hypogammaglobulinemia. However, she never showed any symptoms of Covid-19.

After studying samples regularly collected from the patient's upper respiratory tract, researchers found that viral shedding had continued for at least 70 days in her case while she had the infection at least for 105 days.

.Researchers believe that the reason behind the long-term infection is that the woman was unable to develop any antibodies because of her compromised immune system. However, she never ton to develop symptoms of the infection despite her inability to generate an antibody response.

Researchers further performed deep sequencing on all the virus samples to better understand the mutation of the virus over time. However, they found that the mutation of the virus made no difference.

According to Munster, this is by far the longest case of Covid-19 infection that he had observed.

"We've seen similar cases with influenza and with Middle East respiratory syndrome, which is also caused by a coronavirus," he said. "We expect to see more reports like ours coming out in the future."

"At the time we started this study, we really didn't know much about the duration of virus shedding," Munster said. “As this virus continues to spread, more people with a range of immuno-suppressing disorders will become infected, and it's important to understand how SARS-CoV-2 behaves in these populations.”