The world has built up a lot of immunity in the nine months since the Omicron variant of new strain of corona virus became dominant, fueling a record wave of infections.
Immunity from vaccines and past infections is helping to reduce hospitalizations and deaths even as Omicron’s offspring — a series of sub-variants — become dominant in turn.
Now the virus is trying to find a way around our antibodies. A new sub-variable, BA.4.6, is starting to compete with its predecessor, BA.5. Its advantages include a particular mutation to the mutated protein, the part of the virus that helps it attach to and infect our cells.
We have seen this R346T mutation before. And every time it shows up, it’s linked to forms of the SARS-CoV-2 pathogen with an increasing ability to evade our antibodies. A quality epidemiologist calls “Escape from immunity.”
If BA.4.6 becomes dominant, it could reverse the encouraging trend we’ve seen in most countries in recent weeks of fewer infections, fewer hospitalizations, fewer deaths. .
It’s a reminder that the new coronavirus is a living and evolving organism. When we adapt to it, it adapts to us. Ali Mokdad, professor of health metrology at the University of Washington Institute of Health, told The Daily Beast: “Viruses in general mutate to be more infectious and avoid our immunity.
Do not panic. “One thing I try not to do is get too excited with every new variant that comes out,” Peter Hotez, a vaccine development expert at Baylor College, told The Daily Beast.
Most coronavirus variants and sub-variants appear and disappear without significantly changing the overall direction of the pandemic. Plus, there are a new vaccine in activities that can help us fight, for the long term, even the worst forms of COVID. Final.
All the same, BA.4.6 warrants close attention. It is the seventh major sub-variant of Omicron, which first appeared in Africa in November. It spread rapidly, competing with and replacing the previous major variant, Delta. Epidemiologists have described Omicron and its sub-variants as the most contagious respiratory virus they have ever seen.
Omicron transmits four times more than Delta but half lethal. So Omicron led to worst day ever for new COVID infection when a record 4.1 million people got sick on Jan. 19. That’s a 5x increase from Delta’s worst day in April last year.
But only 13,000 people died in the worst day for Omicron death on February 9 — fewer than the thousands who died on Delta’s deadliest day in January 2021.
It is not difficult to explain the growing gap between infections and deaths as the pandemic reaches its fourth year. Billions of people have been at least partially vaccinated. Billions of people have contracted COVID and survived. The combination of natural and vaccine-generated antibodies has created a global immune wall that eliminates the worst outcomes.
But with BA.4.6, the virus is trying to find a way through that wall. Keith Jerome, a University of Washington virologist, told The Daily Beast: “There is a huge selective pressure to get rid of immunity, especially now that most of the population has acquired immunity. To some extent, from vaccinations, infections, or both.
In essence, SARS-CoV-2 is fighting for its own survival — trying to find mutations until it solves the one that can help it prevail.
R346T is one of those mutations. It’s not entirely clear how the virus makes the change. It is possible that Omicron mixed with an older form of SARS-CoV-2 in a person who had been sick many times. In other words, it is possible that BA.4.6 is a “recombinant” subvariable that chose its most beneficial quality from one of its predecessors.
A change to the mutant protein seems to make it harder for our antibodies to recognize the virus. With R346T, the virus has a better chance to get past our immune system and cause an infection. Even if we are vaccinated. Even we have encountered and overcome COVID in the past.
Greater immune escape means more severe infections. We’ve been lucky with Omicron in the sense that, even if the variant and its sub-variants have driven a wave of resistance in cases since November, hospitalizations and deaths have not increased by the rate. rate.
It remains an open question how much worse BA.4.6 could be and how widespread it might be. Health authorities around the world have been monitoring this complication for months now. Since BA.5 instances are stable, BA.4.6 competes with BA.5 — but not everywhere.
BA.4.6 hotspots include several Australian states and parts of the US Midwest. To date, BA.4.6 accounts for about four percent of new cases in the United States, Canada and the United Kingdom.
The weight of BA.4.6 is set to increase as BA.5 decreases. BA.4.6 seems to have only 10 percent growth advantage than BA.5, but that advantage has increased over time.
If there is good news about the rise of BA.4.6, it is for all its disturbing spikes. still an Omicron subline — and still has a lot of mutations in common with BA.5, BA.4, BA.2 and BA.1.
That means the Omicron-specific boosters that Pfizer and Moderna are developing for their messenger RNA vaccine and that US regulators are watching for approval in the coming weeks, at least still will work against BA.4.6.
BA.4.6 is not the worst case scenario. That would be a sub-variant — or a completely new variant — with a strong immune escape. One form of SARS-CoV-2 has mutated so much that all the antibodies we’ve built over the past three years barely recognize it.
The epidemiological community is divided over the likelihood of this variant developing. Some people believe that respiratory viruses like influenza and the novel coronavirus tend to become milder over time as they become “endemic” — that is, present but often manageable.
Others fear the almost complete inevitability of the immune system to more intelligent viruses as they fight tirelessly to survive. “The idea that each subsequent variant causes less severe disease — I don’t buy that,” says Hotez.
“Viruses have been very successful so far.“
It has to do with genetics – the virus exchanges one quality for another as it tries to spread to more and more hosts. “The trick with viruses is finding a way to get rid of immunity while effectively maintaining the ability to infect new people,” explains Jerome.
“So far, the virus has been very successful in doing so, but the big question is whether it can continue to do so or will instead eventually use up all possible tricks to do so. and move to a more manageable endemic level. There is no way to know for sure yet.”
A variant or sub-variant capable of almost completely escaping the immune system could drag us back to the most horrifying days of the early pandemic, when almost no one had immunity — or any way developing immunity without surviving a very dangerous infection.
But BA.4.6 with the R346T mutation and its ability to escape the immune system could be a preview of that worst-case scenario. It could also be an argument for the pharmaceutical industry and health authorities to redouble their efforts to create a universal vaccine that works against SARS-CoV-2 and every major coronavirus. other, including the score.
There are about a dozen major “pan-coronavirus” vaccines in development. The two leading efforts are at the Coalition for Epidemic Preparedness Innovations in Norway and the US government’s National Institute of Allergy and Infectious Diseases.
They are spending $200 million and $43 million, respectively, to develop their new economy planes. The trials are still months, if not years. “We are taking steps towards a more universal coronavirus vaccine,” Hotez said.
The Pan-coronavirus vaccine may be slightly less effective than the best mRNA vaccine with the highest efficacy (against serious illness and death) of more than 90%, by the end of 2020.
But they will be widely effective, keeping people alive and out of the hospital even if the virus mutates multiple times to survive.
