Explainer: How dangerous is the ‘double mutant’ coronavirus strain from India that causes Covid-19?
SINGAPORE — A new "double mutant" Covid-19 strain that originated from India has set the world on edge, with several countries, including Singapore, imposing longer quarantines on travellers from India or shutting them out altogether. TODAY takes a closer look at the new strain and ask medical experts how much of a concern this new development is.
- The B1617 strain of the coronavirus was first detected in India last year
- It is believed to be driving the country’s latest Covid-19 surge
- Scientists have yet to establish if the strain is more infectious or fatal
- The virus variant has two mutations said to increase disease spread and reduce effectiveness of vaccines
- In Singapore, one expert said the extended isolation period for travellers from India will reduce chances of community spread
SINGAPORE — A new "double mutant" Covid-19 strain that originated from India has set the world on edge, with several countries, including Singapore, imposing longer quarantines on travellers from India or shutting them out altogether.
Experts said that the alarm is due to two mutations of the coronavirus that are known to make the virus more transmissible and reduce the effectiveness of vaccines.
TODAY takes a closer look at the new strain and asks medical experts how much of a concern this new development is.
WHAT IS THIS NEW CORONAVIRUS STRAIN?
The new B1617 strain was first reported in India late last year.
It is common for viruses to mutate but some mutations can make the virus more infectious or even deadlier.
Mutations have been observed in other strains of the Sars-CoV-2 coronavirus that causes Covid-19, but they usually occur as one mutation.
Associate Professor Hsu Li Yang, who heads the infectious diseases programme at the Saw Swee Hock School of Public Health in Singapore, said that the B1617 strain is the first where two mutations have been found together in the spike protein of the virus.
The spike protein is the part of the virus that it uses to penetrate human cells so that it can bind with the cells more effectively and causes infection.
The two mutations are labelled as E484Q and L452R.
IS IT A CAUSE FOR CONCERN?
While scientists have yet to verify if the latest strain is more infectious or deadly, experts said that the L452R and E484Q mutations are a cause for concern, given that they have been known to increase transmissibility and reduce the efficacy of vaccines in other strains.
Dr Anurag Agrawal, director of India’s Council of Scientific and Industrial Research’s Institute of Genomics and Integrative Biology, said in a Bloomberg report last week that the L452R mutation has been shown to increase viral transmission by about 20 per cent and reduce the efficacy of antibodies by more than 50 per cent.
Dr Benjamin Pinsky, medical director of Stanford Health Care’s clinical virology laboratory, told news outlet CNBC on April 8 that if the mutation makes the virus more resistant to antibodies, that could reduce the effectiveness of vaccines and antibody treatments.
“I suspect that existing vaccines will be slightly less effective in preventing infection by this new variant,” he said.
“But all of the vaccines are extremely effective in preventing hospitalisations and deaths.”
Assoc Prof Hsu said it is likely that the B1617 is more transmissible, given that it has become dominant in a short period of time in India where other variants have been identified as well.
HOW DID THE VIRUS TAKE ROOT IN INDIA?
The double-mutation virus is believed to be driving the recent surge in Covid-19 cases in India, which has seen more than 200,000 Covid-19 cases each day since last Thursday.
Speaking to Bloomberg, Dr Anurag said that the prevalence of the variant was more than 60 per cent in some districts in the central Indian state of Maharashtra. He added that its prevalence was expected to rise given the nature of the mutations.
Experts also pointed to other contributing factors that have led to the variant’s surge in India.
Assoc Prof Hsu noted that large rallies and religious gatherings have been permitted in India since the beginning of the year, including the large Kumbh Mela gathering in northern India.
The Hindu pilgrimage, which runs from January to April this year, attracts millions to the banks of the Ganges River.
Moreover, physical distancing has always been a challenge in large Indian metropolises, several of which are inhabited by more people than Singapore’s population, Assoc Prof Hsu pointed out.
“When there is greater spread of the virus, there will be more opportunity for mutations to occur and successful mutants to spread,” he added.
WHAT MEASURES ARE SOME COUNTRIES TAKING
Besides India, the variant has also been detected in other countries such as the United States and United Kingdom. TODAY has asked the Ministry of Health if the variant has been detected in Singapore, too.
To curb the surge of the coronavirus, Indian states such as Gujarat and Maharashtra have imposed curfews and partial lockdowns on their population.
Several Indian states also banned large gatherings during the Hindu festival of Holi last month.
Elsewhere, other countries are restricting travellers coming in from India.
On Tuesday, Singapore extended the stay-home notice from 14 to 21 days for those with a recent travel history to India.
It will also cut the number of approvals for people entering the country if they are not citizens or permanent residents here and have a recent travel history to India.
The UK added India to its travel “red list” on Monday. This means that all those who have visited India recently, with the exception of citizens of the UK or Ireland, are not allowed to enter the UK.
Meanwhile New Zealand suspended incoming travellers from India from April 11 to 28.
Assoc Prof Hsu of the Saw Swee Hock School of Public Health said that although scientific evidence of the transmissibility of the new variant is incomplete, it is understandable that the travel bans are imposed given its rapid spread in India.
He added that in Singapore, the extension of the 14-day stay-home notice period to 21 days, together with the extra tests, mean that “virtually all” Covid-19 cases can be detected, including those caused by a new variant. This would lower the risk of community spread.