BA.2 is like Omicron's sister; Here's what we know about it so far
Queensland, Feb 3 (The Conversation): Cases of the SARS-CoV-2 variant Omicron have escalated globally over the past two months, with many countries experiencing peaks higher than previous variants.
Now we're seeing cases of a sub-variant of Omicron, known as BA.2, emerge in Australia and more than 50 countries.
Rather than a daughter of the Omicron variant BA.1 (or B.1.1.529), it's more helpful to think of BA.2 as Omicron's sister.
Remind me, what is a variant?
Viruses, and particularly RNA viruses such as SARS-CoV-2, make lots of mistakes when they reproduce. They can't correct these mistakes, so they have a relatively high rate of errors, or mutations, and are constantly evolving.
When the genetic code of a virus changes as a result of these mutations, it's referred to as a variant.
Omicron is a highly divergent variant, having accumulated more than 30 mutations in the spike protein. This has reduced the protection of antibodies from both prior infection and vaccination, and increased transmissibility.
When do health authorities worry about a new variant?
If changes in the genetic code are thought to have the potential to impact properties of the virus that make it more harmful, and there's significant transmission in multiple countries, it will be deemed a variant of interest .
If a variant of interest is then shown to be more infectious, evade protection from vaccination or previous infection, and/or impact the performance of tests or treatments, it is labelled a variant of concern .
The World Health Organisation (WHO) classified Omicron a variant of concern on November 26 because of its potential to cause higher reinfection rates, increased transmissibility and reduced vaccine protection.
What is the Omicron lineage?
A lineage, or sub-variant, is a genetically closely related group of virus variants derived from a common ancestor.
The Omicron variant comprises three sub-lineages: B.1.1.529 or BA.1, BA.2 and BA.3.
While the WHO has not given BA.2 a separate classification, the United Kingdom has labelled BA.2 a variant under investigation . So not yet a variant of interest or concern, based on WHO definitions, but one that is being watched closely.
This is not the first variant to have sub-lineages. Late last year, Delta plus or AY.4.2 was reported widely, then Omicron came along.
What's different about BA.2?
While the first sequences of BA.2 were submitted from the Philippines and we have now seen thousands of cases, including in the United States, the UK and some in Australia its origin is still unknown.
The exact properties of BA.2 are also still being investigated. While there is no evidence so far that it causes more severe disease, scientists do have some specific concerns.
1. It's harder to differentiate
A marker that helped differentiate Omicron (BA.1) from other SARS-CoV-2 variants on PCR tests is the absence of the the S gene, known as S gene target failure . But this is not the case for BA.2.
The inability to detect this lineage in this way has led some to label it the stealth sub-variant .
But it doesn't mean we can't diagnose BA.2 with PCR tests. It just means when someone tests positive for SARS-CoV-2, it will take us a little longer to know which variant is responsible, through genome sequencing. This was the case with previous variants.
2. It may be more infectious
Perhaps most concerning is emerging evidence BA.2 may be more infectious than the original Omicron, BA.1.
A preliminary study from Denmark, where BA.2 has largely replaced BA.1, suggests BA.2 increases unvaccinated people's susceptibility of infection by just over two times when compared to BA.1.
The researchers suggest fully vaccinated people are 2.5 times more susceptible to BA.2 than BA.1, and those who were booster vaccinated are nearly three times more susceptible.
The study examined more than 2,000 primary household cases of BA.2 to determine the number of cases that arose during a seven-day follow up period.
The researchers also estimated the secondary attack rate (basically, the probability infection occurs) to be 29% for households infected with BA.1 versus 39% for those infected with BA.2.
This Danish study is still a preprint, meaning it's yet to be checked by independent scientists, so more research is needed to confirm if BA.2 is truly more infectious than BA.1.
We're likely to see new variants We should expect new variants, sub-variants and lineages to continue to emerge. With such high levels of transmission, the virus has abundant opportunity to reproduce and for errors or mutations to continue to arise.
The way to address this, of course, is to try to slow transmission and reduce the susceptible pool of hosts in which the virus can freely replicate.
Strategies such as social distancing and mask-wearing, as well as increasing vaccination rates globally, will slow the emergence of new variants and lineages. (The Conversation)
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Allu Arjun didn't leave theatre despite being told about woman's death: Hyderabad police
Hyderabad, Dec 22: Top Telugu actor Allu Arjun did not leave the theatre during the screening of 'Pushpa-2' on December 4 despite being told to do so in view of a stampede in which a woman died, police officials claimed on on Sunday.
Speaking at a press conference on the annual round-up of 2024, city police commissioner C V Anand showed a video, made by police, on the situation that prevailed when the stampede occurred.
The video was made by collating footage, including from news channels and cell phone clips. It suggests the actor remained in the theatre till the midnight.
Anand did not make any comment on the video, but said the media can draw its own conclusions.
A police official talked about the sequence of events on the fateful night of December 4.
He said that he and other police officials informed a manager of Allu Arjun about the death of the woman and told him that the situation was out of control. He indicated that they were not allowed to meet the actor.
Allu Arjun's staff members told them that they would convey the matter to the actor but did not do so, he said.
The official said he later managed to reach the actor, told him about the woman's death and asked him to leave the theatre so that the fans don't harm each other while trying to catch a glimpse of him.
The official also told the actor that security arrangements would be made for his exit.
However, the actor said he would go only after watching the film, the police official said.
Later, accompanied by a senior officer, the official went inside and brought the actor out, he said.
Amid allegations that bouncers hired by Allu Arjun pushed crowds as well as policemen when the stampede occurred at the cinema hall, the police commissioner warned that stringent action as per law would be taken if THE bouncers indeed misbehaved with the police on duty.
The VIPs would be made responsible for the behaviour of the bouncers hired by them, he said.
Asked if the police would appeal against the interim bail granted to Allu Arjun, the commissioner refused to give a direct response, just saying it is part of the investigation.
What course of action is taken would be known in the days to come, he said.
He also declined to comment when asked if the family of the deceased told him about Allu Arjun's team or film production team allegedly threatening them not to speak on the issue.
Meanwhile, state Cinematography Minister Komatireddy Venkat Reddy found fault with Allu Arjun responding on Saturday to the debate in the Legislative Assembly.
The minister, who observed that the actor should have respect for the government and the chief minister, demanded an apology from Allu Arjun to the government and the CM.
"This government is never vindictive. As Cinematography Minister, we allowed benefit shows and hiking ticket prices to promote the film industry," he said.
However, Union Minister of State for Home Bandi Sanjay Kumar found fault with CM Revanth Reddy for his comments on Allu Arjun in the Assembly on Saturday.
The comments of the CM sounded like character assassination of Allu Arjun and hurting the Telugu film industry, he alleged in a statement.
Later in the day, Sanjay Kumar visited a boy who is undergoing treatment in a hospital after being injured in the stampede.
"Consoled his father over the heartbreaking loss of his wife, Revathi. I pray to god that Sritej recovers at the earliest. Assured support to the family in this difficult time," Kumar said on X.
Earlier in the day, state DGP Jitender told reporters in Karimnagar district that film personalities and all others should understand that safety and security of citizens is utmost important, and also conduct themselves accordingly.
