Why omicron’s BA.5 sub-variant really matters

(CNN) — Once again, covid-19 seems to be everywhere. If you feel like you’ve been caught off guard, you’re not alone.

After the omicron tsunami that swept the United States in January and the lesser increase in cases in the spring caused by the BA.2 subvariant, one would have thought that it was possible to ignore the coronavirus for a while.

After all, the US Centers for Disease Control and Prevention (CDC) estimated in December that almost all americans had been vaccinated or had antibodies from a previous infection. All that immunity would surely give us pause.

But suddenly, many people who had recovered from Covid-19 in March or April found themselves exhausted, coughing and seeing two red lines on a rapid test. How can this happen again, and so soon?

The culprit this time is another descendant of omicron, the BA.5. It has three key mutations in its spike protein that make it better at infecting our cells and more adept at outwitting our immune defenses.

In just over two months, the BA.5 has overtaken its predecessors to become the dominant cause of covid-19 in the United States. Last week, this subvariant caused nearly 2 out of 3 new covid-19 infections in this country, according to the latest data from the CDC.

Laboratory studies of antibodies in the blood of people who have been vaccinated or recovered from recent covid-19 infections have examined their resistance to BA.5, and this subvariant is able to evade them. So people who fell ill with covid as recently as winter or even spring may be vulnerable to the virus again.

“We don’t know the clinical severity of BA.4 and BA.5 compared to our other omicron subvariants,” CDC Director Dr. Rochelle Walensky said during a briefing on Tuesday. Covid-19 response team at the White House. “But we know it’s more transmissible and more elusive of immunity. People who have had an infection before, even with BA.1 and BA.2, are probably still at risk of getting BA.4 or BA.5.”

New wave of covid-19 in the United States with the BA.5 subvariant 2:05

A full wave

The result is that we are getting sick en masse. With Americans now more likely to take faster home tests, the official case count, which currently hovers around 110,000 new infections per day, reflects only a fraction of the true disease burden.

“We estimate that for every reported case, there are 7 unreported cases,” wrote Ali Mokdad, professor of health metrics science at the Institute for Health Metrics and Evaluation at the University of Washington, in an email.

Other experts believe the surge could be up to 10 times greater than what is now being reported.

“We’re probably close to a million new cases a day,” Dr. Peter Hotez told CNN on Monday. “It’s a full-fledged BA.5 surge that we’re seeing this summer. It actually looks worse in southern states, just like 2020, just like 2021,” said Hotez, dean of the National School of Tropical Medicine. at Baylor College of Medicine in Houston.

This puts us in the range of cases reported during the first wave of the omicron variant, in January. Remember when it seemed like everyone was getting sick at the same time? This is still the situation in America.

This may not seem like much, as vaccines and better treatments have dramatically reduced the risk of death from covid-19. However, between 300 and 350 people die on average each day from covid-19, enough to fill a large passenger plane.

“It’s unacceptable. It’s too high,” Dr. Ashish Jha, the White House’s Covid-19 response team coordinator, said during Tuesday’s briefing.

Daily hospitalizations are also increasing in the United States. The fraction of patients requiring intensive care has increased by 23% in the past two weeks. And other countries are also experiencing waves of BA.5.

“I am concerned that Covid-19 cases will continue to rise, which will put additional strain on health systems and strained health workers. I am also concerned about the trend of increasing deaths,” he said. said Tedros Adhanom Ghebreyesus, director general of the World Health Organization, at a press conference on Tuesday after the body’s decision to maintain its emergency declaration for covid-19.

The pandemic, he said, “is far from over.”

What is the challenge of continuous propagation

More treacherous health risks must also be considered. A recent study comparing the health of people who had been infected one or more times with COVID-19 found that the risk of new and sometimes lasting health problems increased with each subsequent infection, suggesting that reinfections are not necessarily benign. .

Although vaccination permanently reduces the risk of contracting covid, a certain percentage of people have long-lasting symptoms after reinfection.

This is another reason why the high number of covid-19 cases is so important: as the virus continues to spread rampantly, it has every chance of mutating into even more adapted and infectious versions of himself. . It does this faster than we can change our vaccines, leaving us stuck in a process of infection and re-infection of covid.

On Tuesday, Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases, called on Americans to use all tools available to stop the spread of the virus, including wearing masks, ventilation and distancing.

“We need to keep virus levels as low as possible, and that’s our best defence. If a virus isn’t replicating and spreading very robustly, it’s less likely to mutate, giving it less likely to evolve into another variant,” Fauci said during a briefing.

In fact, it is already happening.

The BA.2.75 subvariant enters the scene

While the United States grapples with the BA.5 sub-variant, variant hunters around the world are keeping a close eye on another omicron descendant, BA.2.75. It has been detected in a dozen countries, including the United States, and seems to be growing rapidly in India.

BA.2.75 has nine changes in its spicule that distinguish it from BA.2 and about 11 changes from BA.5, according to Tom Peacock, a virologist at Imperial College London.

Several of the BA.2.75 mutations are in a region of the spike protein that is known to be an important place where antibodies bind to stop the virus, said Ulrich Elling, a scientist at the Austrian Academy of Sciences who oversees the coronavirus variants for this country.

There is little information to work on: it is not yet known, for example, how BA.2.75 can compete with BA.5 or if it causes more serious disease. But experts say it has all the hallmarks of a variant that could go global.

“It has already spread to many different countries, so we know it has some resistance,” said Shishi Luo, associate director for bioinformatics and infectious diseases at Helix Labs, which decodes virus samples for the CDC and other customers.

Because of that, and because of the changes in the region of the virus that our antibodies are looking for to inactivate it, “we know in advance that this one will cause problems,” Luo said.

Based on what we know now, he expects this subvariant could lead to a fall surge of COVID-19 in the United States.

In the meantime, says Jha, people must receive the reinforcement within your reach to keep your immunity as strong as possible. US health officials have stressed that people who receive a booster now will be able to receive an updated vaccine this fall that includes the BA.4 and BA.5 strains.

Jha specifically urged Americans 50 and older “if you haven’t gotten your shot this year, get your shot now. It could save your life,” he said.

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