Scientists are hunting for gene link to severe Covid; Japan to bar foreign arrivals over virus variant; UK extends Covid vaccine booster programme

AFP
November 30, 2021

London: All adults in Britain will now be able to get a third Covid jab, a government scientific advisory body said on Monday, as concern mounted about the spread of the new Omicron variant.The...

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London: All adults in Britain will now be able to get a third Covid jab, a government scientific advisory body said on Monday, as concern mounted about the spread of the new Omicron variant.

The move, approved by Health Secretary Sajid Javid, comes as the UK government said it needed to react swiftly to the new variant, which was first detected in South Africa. "We’re advising that the booster programme should now be extended to adults aged 18 to 39 years old," said Wei Shen Lim, of the Joint Committee on Vaccination and Immunisation (JCVI).

Until now, only adults aged 40 and over were eligible for a booster dose six months after their second. At the same time, the advisory body also recommended second doses of vaccine for children aged 12 to 15.

Since last week, the government in London has slapped a travel ban on 10 southern African countries, including South Africa, to try to control the spread of Omicron. It has also reintroduced compulsory testing for travellers, and mandatory mask-wearing in shops and public transport in England, as well as self-isolation for contact cases.

The JCVI approved the government’s proposed expansion of the rollout of booster jabs of Moderna or Pfizer-BioNTech to include more people within a shorter time. Britain is one of several countries to have announced cases of the new variant on their soil, including Germany, Italy and the Netherlands.

Six cases of the new strain were detected in Scotland on Monday, two of them in the largest city of Glasgow. Five others were confirmed in England, Javid told parliament. "We expect cases to rise over the coming days," he added.

"In this race between the vaccines and the virus the new variant may have given the virus extra legs," he told MPs. "So our strategy is to buy ourselves time, and to strengthen our defences," he said of the extension of the booster programme.

Britain, currently chair of the G7 group of nations, on Monday hosted an emergency meeting of health ministers to discuss the Covid crisis. The ministers said in a joint statement that the Omicron variant was highly transmissible and needs "urgent action".

Meanwhile, severe Covid leading to hospitalisation and death overwhelmingly affects the older people and those who already suffer from other illnesses, like heart conditions, kidney disease and diabetes. But young, healthy people can also succumb.

To explain this phenomenon, scientists have been looking at how a person’s genes might make them more susceptible to severe Covid. "You can have people of the same age, same sex and same health overall and they may still react very differently to an infection from SARS-Cov-2," epidemiologist Seiamak Bahram told AFP.

In research published earlier this month, Bahram’s team studied the RNA -- the molecules that interpret genetic coding -- of a group of 94 people during the first wave of the pandemic in France.

The subjects, all under 50 and without other illnesses, included 47 severe Covid patients in intensive care, 25 "non-critical" patients and 22 healthy individuals. By observing how their RNA behaved and comparing the results to a second set of subjects, Bahram was able to zero in on the importance of a gene signature known as ADAM9.

"Some of the genes included in this signature could ultimately become therapeutic targets for severe forms of Covid-19 or acute respiratory distress syndrome," the study published in Science Translational Medicine concluded.

Bahram’s study took a unique approach: most studies looking at how genes affect Covid response involve looking directly at the genome of patients and comparing their illness severity.

In one such study in June last year, researchers looked at 1,980 severe Covid patients from Italy and Spain, comparing them with a similar but otherwise healthy cohort. The study concluded that a cluster of six genes seemed to make patients more vulnerable to respiratory failure.

The practical value of such broad research is limited. Besides only being able to identify the most common genetic mutations, the results are too general to determine how a precise gene might influence the body’s response to Covid.

Another kind of study takes an opposite approach, focusing on known problem genes to see whether they might be causing severe cases of Covid. In this way, researchers under the direction of geneticist Laurent Abel discovered another gene, TLR7, whose mutations altered the immune response in the early stages of infection.

"We looked at genes whose mutations were already known to cause either severe flu or other illnesses like viral encephalitis," Abel told AFP of the research published in August. TLR7 mutations are much more common in men with severe Covid than in the rest of the population. For now, genetics cannot be used to prevent severe Covid.

"We can’t genetically test everyone," says Abel, "it’s not on the agenda, not possible and not reasonable". Instead, he and Bahram say their research could help in the development of treatments.

In a related development, Japan will reinstate tough border measures, barring all new foreign arrivals over the Omicron Covid variant, Prime Minister Fumio Kishida announced on Monday, just weeks after a softening of strict entry rules.

"We will ban the (new) entry of foreigners from around the world starting from November 30th," Kishida told reporters. Japan’s borders have been almost entirely shut to new overseas visitors for most of the pandemic, with even foreign residents at one point unable to enter the country.



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