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Tue Jun 21, 2022, 03:28 AM

Covid: Omicron sub-variants 'evolving to target the lungs and overcome immunity' as UK cases surge

Scientists fear the sub-variants may be similar to the more deadly Alpha and Delta variants

https://www.independent.co.uk/news/health/covid-variant-omicron-cases-wave-b2105586.html

The latest sub-variants of Omicron may have evolved to target the lung, prompting fears the next wave of the Covid could be starting. Hospital admissions for Covid patients in England have begun to grow again, new NHS data shows. The World Health Organisation has been investigating two Omicron sub-variants since April to assess whether they are more infectious or dangerous than their predecessor. Both BA.4 and BA.5 have been added to the agency’s monitoring list.

Last week new figures showed that Covid-19 infections in the UK increased by 43 per cent in the week after the platinum jubilee celebrations, with the two new sub-variants believed to be behind the sudden increase. Additionally, around 1.4 million people in the UK had coronavirus in the week ending 11 June, up from around 990,000 the week before.

According to preliminary data from Kei Sato at the University of Tokyo and colleagues, BA.4, BA.5 and BA.2.12.1 may have evolved to refavour infection of lung cells, rather than upper respiratory tract tissue – making them more similar to earlier variants, such as Alpha or Delta. The propensity of earlier Omicron variants to prefer infecting non-lung tissue may be one reason why infections tend to be milder in most people.

“Altogether, our investigations suggest that the risk of [these] Omicron variants, particularly BA.4 and BA.5, to global health is potentially greater than that of original BA.2,” Sato said. Professor Sato’s experiments indicate that BA.4, BA.5 and BA.2.12.1 replicate more efficiently in human lung cells than BA.2, while further experiments in hamsters suggest that BA.4 and BA.5 may cause more severe disease.

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related:






https://www.nature.com/articles/s41586-022-04980-y

Abstract

SARS-CoV-2 Omicron sublineages BA.2.12.1, BA.4 and BA.5 exhibit higher transmissibility over BA.21. The new variants’ receptor binding and immune evasion capability require immediate investigation. Here, coupled with Spike structural comparisons, we show that BA.2.12.1 and BA.4/BA.5 exhibit comparable ACE2-binding affinities to BA.2. Importantly, BA.2.12.1 and BA.4/BA.5 display stronger neutralization evasion than BA.2 against the plasma from 3-dose vaccination and, most strikingly, from post-vaccination BA.1 infections. To delineate the underlying antibody evasion mechanism, we determined the escaping mutation profiles2, epitope distribution3 and Omicron neutralization efficacy of 1640 RBD-directed neutralizing antibodies (NAbs), including 614 isolated from BA.1 convalescents. Interestingly, post-vaccination BA.1 infection mainly recalls wildtype-induced humoral memory. The resulting elicited antibodies could neutralize both wildtype and BA.1 and are enriched on non-ACE2-competing epitopes. However, most of these cross-reactive NAbs are heavily escaped by L452Q, L452R and F486V. BA.1 infection can also induce new clones of BA.1-specific antibodies that potently neutralize BA.1; nevertheless, these NAbs are largely escaped by BA.2/BA.4/BA.5 due to D405N and F486V, and react weakly to pre-Omicron variants, exhibiting poor neutralization breadths. As for therapeutic NAbs, Bebtelovimab4 and Cilgavimab5 can effectively neutralize BA.2.12.1 and BA.4/BA.5, while the S371F, D405N and R408S mutations would undermine most broad sarbecovirus NAbs. Together, our results indicate that Omicron may evolve mutations to evade the humoral immunity elicited by BA.1 infection, suggesting that BA.1-derived vaccine boosters may not achieve broad-spectrum protection against new Omicron variants.

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Reply Covid: Omicron sub-variants 'evolving to target the lungs and overcome immunity' as UK cases surge (Original post)
Celerity Tuesday OP
Cheezoholic Tuesday #1
The King of Prussia Tuesday #3
SergeStorms Tuesday #4
Duppers Tuesday #2
BumRushDaShow Tuesday #5
Emrys Tuesday #6

Response to Celerity (Original post)

Tue Jun 21, 2022, 04:29 AM

1. Is there a reason initial spikes of sub variants seem to be first discovered in the UK?

Maybe Im wrong but it seems every time a new variant or sub variant makes a run we find out about it from case rises in the UK. Is it because the UK has an abnormally large interaction with other countries handed down from colonial days? Heathrow is one of the largest destinations for international flights in the world, is that it? Seems odd to me.

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Response to Cheezoholic (Reply #1)

Tue Jun 21, 2022, 04:57 AM

3. No.

These new variants were first noted in South Africa, as was omicron itself. The reason for this is that Sputh Africa does a lot of genomic sequencing. African scientists have complained that their work is ignored.
The UK also does a lot of genomic sequencing - an old figure I saw said 44% of the world's total.
Nothing odd about it. The countries with the capacity to look hardest are finding it first.

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Response to Cheezoholic (Reply #1)

Tue Jun 21, 2022, 05:14 AM

4. This time...

it's almost certainly because of the massive crowds associated with the Queen's Platinum Jubilee. That many people together - even in an outdoors event - is bound to be a super-spreader event.

As for earlier spikes.....who knows? London is an extremely international city, with huge numbers of travelers coming and going at all times. It's an international bazaar of infectious diseases.

I don't like what I'm hearing from the WHO. These variants will be hitting their strides when children are returning to school and people are starting to head indoors with the return of colder weather.

It's going to be next to impossible getting people to follow COVID protocols again. Almost everyone thinks the pandemic is over, and the red-state anti-vaxxers are going to spread it like wildfire.

People can't agree on anything these days, and working together to eradicate this virus will be impossible. This will end with blood, feathers, and tears everywhere.

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Response to Celerity (Original post)

Tue Jun 21, 2022, 04:33 AM

2. Thank you!

Hope the idiots who chided me for continuing to wear a mask don't object.

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Response to Celerity (Original post)

Tue Jun 21, 2022, 05:46 AM

5. This was CDC's "Nowcast" published last week for the week prior (new one due Wednesday)

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Response to Celerity (Original post)

Tue Jun 21, 2022, 07:22 AM

6. This surge in the UK isn't much of a surprise.

Even here in Scotland, which has generally been more cautious in its approach to countermeasures, I'm often pretty much the only person masking up in supermarkets etc., which is a big turnaround over the last six weeks or so and quite disappointing. The messaging from Westminster hasn't helped at all - they want to pretend it's a past problem, which may well come back to bite us all in the arse by the time winter rolls in, if not long before then.

In our smallish village, it's rife, and yesterday my partner tested positive, so now I have the joyous wait to see whether I test positive too or miraculously escape it.

Our friends who've had it describe whatever variant is going round locally as "not nice", with general fluey symptoms, hacking coughs and some reports of copious lurid phlegm in the middle and later stages. It hasn't totally laid any of them out for long, though one friend is still testing positive after nine days, but he's up and about and feels like he's got some energy back now.

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