COVID-19: Top science stories of the week, from mutant viruses to 3-D mapping of spike proteins

A new study published this week in the Lancet shows that a mutation in the SARS-CoV-2 virus is linked to milder symptoms than those caused by a virus without the mutation.

The mutation, which causes a deletion of two genes called ORF7b and ORF8, was identified earlier on this year when researchers in Singapore found a cluster of COVID-19 cases caused by the virus with the genetic mutation. The researchers compared the symptoms of those with the mutated version of the virus with symptoms of patients infected by the unmutated version and found that none of the 29 people infected with the mutated version needed supplemental oxygen. By comparison, 28% (26 out of 92) people whose viruses did not have the mutation did need oxygen.

The mutated version of the virus has not been detected since March but the researchers note that the virus responsible for the 2002-2004 outbreak of severe acute respiratory syndrome (SARS) also acquired a mutation that caused a deletion in the ORF8 gene, suggesting an important adaptation mechanism of the virus. Further studies of genetic variants of the virus are needed as they will have implications for the development of treatments and vaccines.

Researchers at the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK, have published the first detailed analysis of the spike proteins on the SARS-CoV-2 virus.

For the study, published in Nature, researchers collected viral particles from infected cells and used electron microscopy to visualize and determine the shape of the spike proteins that decorate the surface of coronaviruses. The spike proteins help the virus to enter human cells and having such a detailed mapping them will help researchers better understand interactions between the spike protein and neutralising antibodies during infection or vaccination.