The new BA.4.6 COVID variant is becoming a familiar nightmare

In the nine months since the Omicron variant of the novel coronavirus took hold, the world has built up a lot of immunity, fueling a record wave of infections.

Even if Omicron’s descendants (a series of sub-variants) dominate one after the other, immunity to vaccines and past infections helps reduce hospitalizations and deaths.

Now the virus is trying to find a way to bypass our antibodies. The new sub-variant BA.4.6 begins to surpass its predecessor BA.5. Its advantages include specific mutations to the spike protein, the part of the virus that helps it grab onto and infect our cells.

We have seen this R346T mutation before. Every time it appeared, it was associated with a form of the SARS-CoV-2 pathogen, enhancing its ability to evade our antibodies. A good epidemiologist calls this “immune evasion.”

If BA.4.6 becomes dominant, it could reverse the encouraging trend we have seen in most countries in recent weeks, namely fewer infections, fewer hospitalizations, fewer deaths.

It’s a reminder that the novel coronavirus is a living, evolving thing. When we adapt to it, it adapts to us. “Viruses often mutate to be more contagious and avoid our immunity,” Ali Mokdad, a professor of health metrics sciences at the University of Washington Health Institute, told The Daily Beast.

do not panic. “One of the things I try not to do is get too excited about every new variant that comes out,” Peter Hotez, a vaccine development expert at Baylor College, told The Daily Beast.

Most coronavirus variants and subvariants appear and disappear without significantly changing the general direction of the pandemic. In addition, there is a new vaccine in development that could help us fight even the most severe forms of COVID over the long term. finally.

Nonetheless, BA.4.6 deserves close attention. It is the seventh major sub-variant of Omicron and first appeared in Africa in November. It spread quickly, surpassing and replacing the previous main variant, the Delta. Epidemiologists describe Omicron and its subvariants as the most contagious respiratory viruses they have ever seen.

Omicron is four times more contagious than Delta, but half as deadly.So Omicron causes worst day ever for new COVID Infect On January 19, a record 4.1 million people fell ill. That’s a fivefold increase from the worst day for Delta last April.

But for Omicron, the worst day only saw 13,000 deaths death toll Feb. 9 — Thousands fewer deaths than Delta’s deadliest day in January 2021.

As the pandemic enters its fourth year, it’s not hard to explain the widening gap between infections and deaths. Billions of people are at least partially vaccinated. Billions of people have contracted the coronavirus and survived. The combination of vaccine-induced and natural antibodies creates a global immune wall that slows down the worst outcomes.

But with BA.4.6, the virus is trying to get around this wall. Keith Jerome, a virologist at the University of Washington, told The Daily Beast: “Immune escape is under enormous selective pressure, especially now that the vast majority of people have some level of immunity, whether it’s immunization, Infection or both.”

Essentially, SARS-CoV-2 is fighting for its own survival—trying to mutate until it finds one that might prevail.

R346T is one of these mutations. It’s not entirely clear how the virus makes this change. It’s possible that Omicron mixed with an older form of SARS-CoV-2 in a person who got sick more than once. In other words, BA.4.6 may be a “recombined” sub-variant that has acquired the most favorable qualities from one of its predecessors.

This change in the spike protein appears to make it harder for our antibodies to recognize the virus. With R346T, the virus is more likely to slip past our immune system and cause an infection. Even if we have been vaccinated. Even we have found and overcome COVID in the past.

Greater immune escape means more and more severe infections. In a sense, we’ve been lucky with Omicron that even though the variant and its sub-variants have driven back-to-back waves in cases since November, hospitalizations and deaths have not risen proportionally.

It’s still an open question how much BA.4.6 might get worse and how far it might spread. Health agencies around the world have been tracking this subvariable for months. As BA.5 cases stabilized, BA.4.6 outperformed BA.5, but not everywhere.

BA.4.6 Hotspots include some states in Australia and parts of the US Midwest. So far, BA.4.6 accounts for about 4% of new cases in the US, Canada and the UK.

The proportion of BA.4.6 will rise as BA.5 falls. BA.4.6 only seems to have a 10% growth advantage over BA.5, but that advantage has been growing over time.

If there’s good news for the rise of BA.4.6, it’s all its worrying mutations still An Omicron sublineage – and still has many of the same mutations as BA.5, BA.4, BA.2 and BA.1.

This means that the Omicron-specific booster Pfizer and Moderna are developing for their messenger RNA vaccines (which U.S. regulators are expected to approve in the coming weeks) should at least partially counter BA.4.6.

BA.4.6 is not the worst case. That would be a sub-variant or a completely new variant with strong immune evasion. One form of SARS-CoV-2 is so mutated that it is barely recognized by all the antibodies we’ve built over the past three years.

The epidemiological community is divided on the possibility of this variant evolving. Some people believe that respiratory viruses like the flu and the novel coronavirus will become “endemic” over time and generally milder — that is, always present but usually manageable.

Others worry that almost complete immune escape is almost inevitable for clever viruses as they fight tirelessly for survival. “The idea that each subsequent variant causes a less severe disease — I don’t believe it,” Hotez said.

So far, the virus has been very successful.

It comes down to genetics — the virus trading one quality for another as it struggles to spread to more and more hosts. “The trick with viruses is to find a way to evade immunity while still maintaining the ability to effectively infect new people,” Jerome explained.

“The virus has been very successful so far in this regard, but the big question is whether it can continue to do so, or will eventually exhaust all possible means to do so and stabilize to a more manageable epidemic level. Not sure yet.”

Variants or sub-variants with almost complete immune evasion could drag us back to the scariest early days of the pandemic, when almost no one was immune — or whatever develop Immunity without surviving a very dangerous infection.

But BA.4.6 with the R346T mutation and immune escape potential may be a preview of the worst. Redoubled efforts to develop a universal vaccine against SARS-CoV-2 and all other major coronaviruses could also be an argument for the pharmaceutical industry and health agencies, of which there are dozens.

About a dozen major “pan-coronavirus” vaccines are in development. The two main pieces of work came from the Coalition for Epidemic Preparedness Innovations in Norway and the U.S. government’s National Institute of Allergy and Infectious Diseases.

They spent $200 million and $43 million, respectively, to develop new generic jabs. Trials are still months or even years away. “We are gradually developing a more general coronavirus vaccine,” Hotez said.

As early as late 2020, pan-coronavirus vaccines may be slightly less potent than the best mRNA vaccines, with peak potency (against severe illness and death) exceeding 90%.

But they would be broadly effective, keeping people alive and out of hospital, even as the virus mutates again and again in order to survive.

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