Children and young adults with compromised immune systems, such as those undergoing cancer treatment, may experience a prolonged period of infection with SARS-CoV-2, the virus that causes COVID-19, a study finds.
The extended duration of the infection may also increase the incidence of mutations, said researchers at Children’s Hospital Los Angeles (CHLA), USA.
In the study, published in the journal EBioMedicine, the team described two children and a young adult with acute lymphocytic leukemia who tested positive for SARS-CoV-2 for months. Lymphoblastic leukemia is a cancer of the blood and bone marrow that affects white blood cells.
While most people are contagious for about 10 days after first showing Covid symptoms, this is the first report of active long-term symptoms and infection in a pediatric or young adult population, said lead author Jennifer Dien Bard, director of Clinical Microbiology. and Virology Laboratory at CHLA.
According to Bard, SARS-CoV-2 mutates about once or twice a month. A long infection period raises concerns about the development of viral mutations. When a virus replicates, it copies its genetic code, but sometimes the virus makes a mistake known as a mutation.
Most mutations have no effect on how the virus behaves or the disease it causes, but some can cause the virus to behave differently. For example, the B117 SARS-CoV-2 variant, which has 17 mutations, is considered more contagious than other virus variants.
There is some evidence that the B117 variant may have developed in a person who was immunocompromised and consistently infected with SARS-CoV-2. But even in immunocompromised patients, infections for months are rare, Bard said.
“We’ve had many other immunocompromised patients who haven’t gone through these long-term infections, but it’s something to be aware of, and hospitals may want to consider changing infection control policies to address this particular population,” Bard said.