SINGAPORE: Researchers in Singapore have discovered a new COVID-19 variant that causes less severe symptoms in patients, opening up new avenues for vaccine development and treatments.
The variant of SARS-CoV-2 - the virus that causes COVID-19 - was first detected in Singapore in three patients who had arrived from Wuhan in the early stage of the pandemic.
It was later transmitted across several clusters in Singapore before being contained, said the National Centre for Infectious Diseases (NCID), A*STAR’s Singapore Immunology Network (SIgN) and Duke-NUS Medical School in a press briefing on Friday (Aug 21).
Patients who had contracted the milder variant were less likely to develop low blood oxygen or required intensive care, according to the study.
The findings were recently published in international scientific journal The Lancet.
While the variant has stopped circulating in Singapore since early March, NCID executive director Prof Leo Yee Sin said the discovery has large implications for researchers’ understanding of the virus, and therapeutic and vaccine development.
LESS SEVERE SYMPTOMS IN PATIENTS
The milder variant has a large mutation or deletion in a region of the virus known as ORF8.
In a sample of 39 patients with the milder variant, three patients developed low blood oxygen and required supplemental oxygen, compared with 26 out of 92 patients with the non-mutated or wild-type virus.
Even adjusting for other factors including age, gender and chronic medical conditions, patients with the deletion variant showed less severe symptoms, said NCID consultant Dr Barnaby Young.
Researchers studied 131 people infected with either the wild-type, the deletion variant or a mix of both types of SARS-CoV-2 virus.
Data suggests that ORF8 deletions emerge in response to the human immune system response. Other types of deletions in the ORF8 region have also been detected globally.
However, Prof Gavin Smith from the Emerging Infectious Diseases Programmes from Duke-NUS Medical School stressed that “it’s not unusual for different variants, or different versions of a virus to be generated throughout the course of an outbreak”.
Similar deletions in ORF8 were also detected in Severe Acute Respiratory Syndrome (SARS) in 2003, but the exact function of the ORF8 protein is obscure, the institutes said in a press release.
“I will tell you that there is (a lot of) excitement among us, as researchers, when we found this new variant. It opens up a lot of scientific basis and background for us to understand, each genetic segment, what it means to the virus, and what it means when it interacts with the human host,” said Prof Leo.
"At least with this point, we understand with the deletions of these particular regions, the disease is actually milder in manifestations,” she added.
The discovery will allow researchers to target that region with medication, said Prof Leo, adding that the information could also support vaccine development.
“It’s very exciting … It opens up a lot of areas of investigation for a pathogen that we still don’t know an awful lot about,” said Prof Smith.
Further studies to understand the function of the ORF8 protein and the effects of removing this protein are ongoing.