Researchers in Singapore have discovered a new variant of the Covid-19 coronavirus that causes milder infections, according to a study published in The Lancet medical journal this week.
The study showed that Covid-19 patients infected with a new variant of SARS-CoV-2 had better clinical outcomes, including a lower proportion developing low blood oxygen or requiring intensive care.
The study also showed the variant, which has a large deletion in a part of its genome, elicited a more robust immune response.
The study involved researchers from various Singapore institutions, including the National Centre for Infectious Diseases (NCID), the Duke-NUS Medical School and the Agency for Science, Technology and Research.
"These studies provide the first convincing data showing that an observed genetic change (mutation) in SARS-CoV-2 has affected the severity of disease in patients," said Gavin Smith at Duke-NUS.
The scientists said the findings had implications for vaccine development and treatments for Covid-19.
The variant, which likely came from Wuhan, China, was detected in a cluster of infections that occurred from January to March 2020. In Singapore, the virus was transmitted from person-to-person across several clusters before being contained.
An expert told Reuters this week that mutations in viruses may be "a good thing". Viruses tend to become less virulent as they mutate so as to infect more people but not to kill them as they depend on the host for food and shelter, according to Paul Tambyah at Singapore's National University Hospital.