The astounding spread of BA.5 shows why the COVID wave in California is so different

People shop and work at Santee Ally on Mondays. Public health officials recommend staying up to date on vaccines and boosters, getting tested before attending gatherings or events, and wearing masks when in indoor or crowded public spaces. (Jason Armond/Los Angeles Times)

With California suffering another severe coronavirus wave, the astonishing spread of the BA.5 variant is becoming a growing focus of scientific scrutiny, with experts saying it may replicate itself more effectively than previous versions of Omicron.

Compared with its predecessors, the newest Omicron sub variant, BA.5, may have an enhanced ability to generate a large number of coronavirus copies once it enters human cells, a potential contributing factor to the problematic cause of the summer Omicron wave.

Far and away from the dominant version of the coronavirus spreading across the country — which made up an estimated 65% of new cases over the week to Saturday, according to the US Centers for Disease Control and Prevention — BA.5 arguably combines aspects of last summer. Dr. said. Eric Topol, director of the Scripps Research Translational Institute in La Jolla.

“You may remember the term ‘Deltacron’ used prematurely many months ago in the epidemic. But the ability to infect cells for BA.5 is closer to Delta than the previous Omicron family of variants,” Topol wrote in a blog post.

In many ways, this pandemic wave felt different than other Omicron waves earlier this year. Health experts say the behavior of the highly contagious strain shows the need for wise precautions.

Citing a prepress report from Australia, Topol cited data in a lab study that BA.5 was found to produce significantly more copies of the coronavirus than the previous Omicron alternative, BA.2.

In his letter, Topol wrote: “There are more copies of the virus because BA.5 has a much better ability to get into cells… which may help explain why this version of the virus causes so much trouble, than the other sub variants of Omicron.” . .

Dr. said. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco.

But the potential key to this scenario is the emergence of another Omicron variant, BA 2.75, which has raised concerns in India.

“I know it is very frustrating,” Qin Hong said. However, he said, there are ways to live life while taking steps to reduce risk.

Common steps that public health officials recommend include keeping up with vaccines and boosters, testing before attending gatherings or events, and wearing masks when in indoor or crowded public spaces.

Separately, BA.5 appears to have doubled Omicron’s previous trait of ‘immune escape’, that is, the virus’s ability to escape the human body’s immune response caused by previous vaccinations or infections.

From early March through early May, California reported about 2,300 infections weekly. By mid-May to mid-June, the state was reporting about 10,400 cases of re-infection weekly — around that time BA.5 and another closely related variant, BA.4, began spreading widely.

The first Omicron variant, BA.1, which spread rapidly in the United States after Thanksgiving, already had dozens of mutations that made it difficult for our immune systems to identify it.

“What has now happened is that with BA.5, it has imposed mutations above BA.1 which makes it difficult for our immune system to recognize it,” Topol said.

Also disturbing were the preliminary data in the Australian study indicating a low efficacy of Evusheld, a monoclonal antibody, against BA.5.

“This is another advantage of immune escape, which is that the monoclonal antibodies don’t work very well,” Topol said.

The question of whether BA.5 leads to more serious disease in humans has not been settled.

Chen Hong said data from South Africa indicates that BA.5 has not changed the risk of hospitalization compared to previous versions of Omicron.

Coronavirus infection rates have remained at consistently high levels statewide for months, infecting large numbers of people and disrupting business operations. Increasingly, more patients with coronavirus are being examined in hospital.

During the week period ending Thursday, California reported an average of more than 15,500 new coronavirus cases per day. On a per capita basis, about 278 cases per week per 100,000 residents. That’s down 12% from the previous week, but officials and experts say the apparent dip may be in part as a result of data outages over the July 4th weekend.

The rate of coronavirus cases in Los Angeles County has been relatively stable over the past week but remains high, at about 5,400 cases per day. On a per capita basis, there are 373 coronavirus cases per week per 100,000 residents.

The official numbers are almost certainly understated due to the widespread use of at-home tests – the results of which have not been reliably reported.

Statewide, 4,227 patients with coronavirus were hospitalized as of Monday, the highest single-day total since late February. In Los Angeles County, the last patient count was 1,153, up 54% from the previous two weeks.

Although a significant proportion of these patients are not hospitalized with complications from COVID-19, and may incidentally test positive after seeking care for another reason, officials say they are nonetheless a particular strain on resources due to the additional services needed to maintain them. them from spreading the virus.

As long as transmission remains high, health care systems are unlikely to see much improvement.

“With more cases, it is clear that we are seeing more people who need medical care — and not just in our hospitals, but also in our emergency departments and urgent care centers that are full of many people who need care for their COVID-related illness,” the health director said. County General Barbara Ferrer during a recent briefing.

COVID-19 deaths are starting to increase in Los Angeles County as well, from about 50 deaths a week in early June to nearly 100 deaths a week now. At the height of the Omicron winter wave, Los Angeles County was reporting more than 500 deaths a week.

In earlier altitudes, dominant strains such as the last summer’s Delta or the Alpha were previously stuck in for relatively long periods and were not displaced by their successors quickly, which means that an affected individual can have a high degree of protection perhaps for several months.

This schedule is significantly shortened in the Omicron region. Since only April, three different subvariants – BA.2, BA.2.12.1 and now BA.5 – have been estimated as the predominant strain nationwide. This rapid succession means that it is possible for a person to have a previous version of Omicron and then have it again with a later version several weeks later.

“A lot of people may have recently contracted the virus, again, in three or four weeks, versus the old days, where they had a three-month period” where they are less likely to get infected again, Chen Hong said.

Qin Hong said he was familiar with people who, after being infected, thought she had given them permission to “go out more and not worry too much”, only to get stuck with recurring infections. “That line of reasoning is not great when you have a change of guard” of Omicron’s variants, he added.

While some people remain asymptomatic or have mild symptoms, others report severe discomfort, including a high fever, severe afternoon soreness, brain fog, and fatigue that can last for weeks – or possibly the onset of prolonged COVID, in which Symptoms of the disease persist for months or years.

It is also possible that some of those who have avoided infection until now are no longer using some of the protective measures they did before, or are exposed to family members and friends who have relaxed protective practices.

Qin Hong said that people “take more risks; they move; they travel.” Even in San Francisco, Chen Hong said, a number of people aren’t wearing masks in places where they were once ubiquitous, which means there’s less peer pressure to wear masks in areas that were once common.

These measures remain largely voluntary at this point in many public places, but recent increases in coronavirus-infected hospitals have prompted Los Angeles County to potentially issue a new mask order that could be applied to indoor public spaces. The county already requires hiding on public transportation and at airports, health care facilities and nursing homes, as well as at work sites where there have been three or more coronavirus cases over a two-week period.

If current trends continue, Los Angeles County could move from the average community level for COVID-19 — which is determined by the US Centers for Disease Control and Prevention, case factors and hospitalization rates — to the high level as soon as Thursday.

If the county is at the high community level for COVID-19 over the three consecutive Thursdays, health officials will be willing to implement a new global mask mandate in indoor public spaces for those age 2 and older starting July 29.

This story originally appeared in the Los Angeles Times.

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