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Mutation makes COVID-19 less serious

Viral particles (in blue) of SARS-CoV-2

Hannah A Bullock / Azaibi Tamin / CDC

A mutation that erased a stretch of DNA from two SARS-CoV-2 genes appears to make the symptoms of COVID-19 less aggressive. A team led by molecular biologist Lisa Ng of the Singapore Immunology Network monitored the progress of the disease in 29 patients who had contracted a version of the coronavirus with the genetic alteration, observing that none of them needed to receive supplemental oxygen (Lancet, August 18). In another group of 92 COVID-19 patients infected by a strain of the pathogen without the mutation, 26 individuals had to use artificial respirators. SARS-CoV-2 variants with the genetic alteration were circulating in Asia at the beginning of the pandemic, but the mutation, which affects the ORF8 and ORF7b genes, has not been identified since March. During the Severe Acute Respiratory Syndrome (SARS) outbreak in the early 2000s, the virus that causes the disease also had a mutation in the ORF8 gene.