Half of UK passengers potential carriers of new COVID-19 strain

Genomic experts from India believe that about half of the passengers travelling from the United Kingdom who have tested positive for the coronavirus could be potential carriers for the new strain of the virus found in the country earlier this month. As of now, 20 passengers from the UK have tested positive for COVID-19 in India.

"We know that of the UK passengers that have come to India yesterday, 20-odd have been found to be positive. Moreover, currently this strain is in 60 per cent of the positives in the UK. By that calculation, it is very likely that of these 20, half of them may be carrying the new variant. If they came from the town where the new variant is not detected that could also be a matter of chance. But there is a high probability that some of them will be carrying the new variant," Dr Rakesh Mishra, Director at the Centre of Cellular and Molecular biology (CCMB), Hyderabad told India Today.

Shedding light on how to manage prospective carriers of the new strain, Mishra said that testing those who had returned a month ago will be futile as they "may have already turned asymptomatic and spread whatever they had to others."

The newly arrived infected people from the UK have been identified and contained, and will be quarantined separately, informed the expert.

The new variant - B.1.1.7 - has left the world abuzz with questions and concerns, while many countries including India have suspended international travel ties with the United Kingdom. On Tuesday, 20 passengers that arrived in India from the UK tested positive.

The samples of the 20 passengers that tested positive on Tuesday have been collected and will undergo genome sequencing in Indian laboratories. "We need to track those who came from the UK in a couple of weeks and genome sequence their infections. Irrespective of this, a large number of fresh infections should also be genome sequenced from major cities and places to independently assess if this virus had been around before and its extent," informed Dr Mishra.

What does the COVID-19 mutation mean?

Speaking of virus mutations, Dr Mishra said that it is a rather normal occurrence, with viruses doing it faster because "they don't do error corrections in their evolution, hence, whatever error their mechanism puts in during the replication or copying of their RNA, it stays. Hence, they mutate faster. There is a reason we don't have a vaccine against influenza, every year it changes so much that the vaccines become ineffective."

Having said that, he added that for SARS-CoV-2 the mutations are occurring slower.  "We are only looking at disturbances in several months," he said.

Also read: New coronavirus strain in the UK not 'out of control', says WHO

New strain is 70% more likely to infect

According to Dr Mishra, the new strain has alterations in a specific part of the virus that enables the virus to attach itself to human cells in an easier fashion. He attributes this to be the reason for the mutation to be highly infectious, adding that "there is about 70 per cent more chance that this strain will infect more as compared to the existing strains of SARS-COV-2."

While the precautions and treatments remain the same for the new strain as well, Dr Mishra expressed concern about the potential problems that might ensue if people in high numbers start getting affected. "It may result in overcrowding in hospitals and that could lead to a partial collapse of the healthcare system," he said.

"At this point, we are lucky to have found out that there is another strain that has emerged. If it is somewhere in the country, we should put measures in place to prevent or reduce the spread of this virus," he added.

India needs to increase genome sequencing

"We haven't found this strain in the Indian population yet. It is possible we have not looked hard enough to find it. We have been testing less and sequencing even lesser., Normally it is recommended that in a few hundreds, one or two isolates should be sequenced to check the kind of mutations that are going around. We have been sequencing 10-fold less, even at the national level. That's something we need to step up now," Dr Mishra said.

There have been more than 4000 virus isolates of COVID-19 sequenced in India, with several thousand documented, but all in vain. According to Dr Mishra, the results get documented and then disappear from the population, exacerbating the initial problem of low sequencing.

Testing for the new variant

Emphasising on the importance of genome sequencing once more, Dr Mishra said that  "Some variants may not be picked up by the RT-PCR method... but this variant will be picked by the current RT-PCR. That's why genome sequencing is important because it helps find out if the sequences are changing." About the rapid antigen test, he said that those could miss the mark about 50 per cent of the time.

Will this have an impact on coronavirus vaccines?

Dr Mishra believes that the one mutation detected as of now should not act as a hindrance in the functioning of the vaccines, since there are also multiple vaccines being developed.

"Even vaccines like Moderna, Pfizer that are mRNA vaccines which target one protein, are targeting the protein that mutated in the UK variant. Vaccines also create multiple antibodies. There is a very small chance that the vaccines won't work. It will be effective," he said.

He further indicated that India will be able to ascertain the extent and the spread of the new variant from the UK within a few days' time. "We have been contacted by the central and state authorities. There are five centres that will sequence the genome. There are four others including National Institute of Virology, Pune," informed the expert.

Also read: Immune system 'remembers' coronavirus for 8 months post infection, shows study