Screening for coronavirus mutations linked to the variant first reported in India now forms part of regular Covid-19 surveillance in Hong Kong, health authorities have revealed, after it emerged the mutated strain was identified in at least 10 previously confirmed imported cases.
The researcher behind the imported infections discovery has called on the government to step up monitoring processes for the potentially more infectious variant, which is being investigated by scientists around the world.
Polytechnic University’s findings show that the 10 cases with the variant – officially known as B.1.617, or by its sub-lineage B.1.617.1 – were all imported from India, with most arriving in Hong Kong early this month.
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Dr Gilman Siu Kit-hang, the health, technology and informatics department associate professor who led the research, said the government’s flight ban mechanism should be expanded to include the new variant. The safeguard recently barred all flights from the country.
“The Centre for Health Protection might have missed some cases initially, as they only look at infections with the N501Y mutation, while the variant from India doesn’t have that mutation,” Siu said.
While the N501Y mutation can be found in the three “variants of concern” first identified in Britain, South Africa and Brazil, it is absent in the B.1.617 variant from India.
Currently considered a “variant of interest” by the World Health Organization, B.1.617 contains two prominent mutations – L452R and E484Q – which might help the virus transmit more easily and evade immune systems. It has spread to at least 17 countries.
CHP controller Dr Ronald Lam Man-kin told a Friday press conference the health authorities were already looking for those two mutations as standard when conducting initial genome sequencing on confirmed Covid-19 cases in the city.
“For E484Q and L452R, we have already added them into our regular genomic screening [among Covid-19 cases],” Lam said, without specifying when the change was made.
But contrary to the PolyU findings, Lam said the CHP had only detected one case with the variant, involving an imported infection, although he did not specify when that case was recorded.
Concern over the variant has mounted amid a skyrocketing coronavirus caseload in India, where records were set nearly every day in the past week – jumping from 332,730 cases a week ago to 386,452 on Friday.
Among the 10 imported cases with the variant discovered in Hong Kong, seven arrived on Vistara flight 6395 from New Delhi on April 4. A total of 58 passengers on that flight have so far tested positive for Covid-19, including one on Friday.
But the 10 cases might only be the tip of the iceberg, as Siu did not have access to viral specimens for all the infected passengers on the flight.
Genome sequencing now being conducted by the University of Hong Kong’s school of public health, tasked by health authorities with looking into the cases, could potentially uncover more with the variant.
A source said more than seven cases involving that variant were identified from the flight, but other forms were also detected.
While the authorities were already screening for mutations linked to the variant from India, Siu called for them to be added to the list of mutations that would trigger a 14-day flight ban, if discovered on routes.
Currently, the ban is triggered if at least five passengers from a country, regardless of the airline, are found to be carrying the N501Y mutant strain when tested on arrival.
The government announced on Thursday night that the ban would also be triggered if at least 10 passengers from a country in a week were found carrying N501Y or “relevant virus mutations” from all forms of testing, including those in quarantine. It was not immediately clear what other mutations were included in the mandate.
In a response to the Post, the Food and Health Bureau said other virus mutations would – depending on the actual situation – be added to the suspension list “if they pose similar risks to Hong Kong’s public health”.
When asked whether the government would further tighten the flight ban policy, health minister Professor Sophia Chan Siu-chee told the press conference that the government had already strengthened the criteria.
The discovery of the Indian variant in Hong Kong comes as health officials have been put on high alert after a domestic helper living in Tung Chung was confirmed on Thursday to have contracted a Covid-19 variant from an unknown source locally – a first for the city.
More than 900 residents of a housing block were subsequently evacuated and sent to government quarantine facilities.
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This article Coronavirus: mutated variant from India found in 10 Hong Kong Covid-19 cases first appeared on South China Morning Post