BA.5: New coronavirus variant threatens another surge in N.M.

Jul. 14—The latest strain in what seems to be the coronavirus's endless mutations is the most transmissible and evasive one yet.

The variant known as BA.5 is swiftly gaining a foothold in New Mexico and is almost certain to become the dominant coronavirus strain here, just as it has in the U.S. and much of the world.

This omicron offshoot can evade a person's immunity bolstered by vaccines and previous infections, making it harder for everyone to avoid — a clear sign the pandemic is far from over.

BA.5 and its cousin BA.4 made up roughly half the cases in the state during the last genetic sequencing conducted a few weeks ago, and that percentage is sure to grow due to how highly contagious the variants are, said Steven Bradfute, viral immunologist at the University of New Mexico.

"We are mirroring the trends nationwide," Bradfute said. "If we're not there now, we probably will be soon."

A recent White House report said these two variants account for 80 percent of COVID-19 cases in the country.

Bradfute said when a new virus or variant emerges, New Mexico tends to initially lag behind many other states because of its lower population density but it usually catches up.

Nationally, the consensus among health experts is BA.5 will overtake BA.4 and become the predominant strain, following the normal pattern of viral evolution.

State health officials declined to comment for this story, saying they wanted to wait until Thursday's COVID-19 news conference to offer analysis and information on BA.5.

One bright spot: Although BA.5 is increasing case counts and the number of hospitalizations, it's not causing a noticeable rise in intensive-care admissions.

"It doesn't appear so far to cause more severe disease," Bradfute said.

BA.5 can ward off antibodies from vaccines that targeted earlier coronavirus strains because of changes in its spike proteins.

"Unfortunately, BA.5 is smarter and more efficient in spreading," said Dr. Jagdish Khubchandani, public health professor at New Mexico State University. "The job of a virus is to mutate, and our job is to mitigate."

Its rate of transmission is substantially higher, though experts vary in their estimates of how much.

Transmission rate is measured by how many people are likely to catch the virus from an infected person.

For the early coronavirus strains, it was three, which then escalated to somewhere between seven and nine with the first omicron variants, Bradfute said. The number is higher for BA.5, perhaps in the teens, but it's too early to say with any certainty, he said.

Some researchers have claimed the transmission rate is 18 — putting it on par with the measles, the most infectious disease in the world. But those estimates are premature, Bradfute said.

Pfizer and Moderna are working on vaccines that specifically combat BA.5. They are expected to be rolled out some time in the fall.

The current shots, though less effective in thwarting this variant, still reduce the severity of symptoms and should be taken to help avoid long COVID-19 and death, according to the Centers for Disease Control and Prevention.

Khubchandani said the case counts are drastically underreported, a problem that has arisen with reduced state and federal funding for testing, less sequencing and more people testing themselves at home.

There's also a growing complacency toward a disease that appeared to be waning.

"I would estimate that the true number of cases is at least two to three times higher than what is reported," Khubchandani said.

Although BA.5's symptoms are milder than earlier strains that filled emergency rooms, the rapid spread and skyrocketing cases could prove troublesome, he said.

The sheer caseload could overwhelm medical services, delay care for other health problems, increase workers' sick leave and amp up people's stress and fears — the same issues seen when the pandemic last intensified, he said.

Getting a pandemic-weary public to resume safety measures such as testing, masking and avoiding crowds will be challenging, especially in the summer when people want to get out and travel, he said.

But the effort must be made, he said.

"We should ramp up testing and educate the public about this new variant and the need to test and isolate," Khubchandani said.

Some health experts are hopeful the less severe symptoms of the recent strains, including BA.5, signal the disease is moving into the endemic phase in which it becomes like the seasonal flu.

But Bradfute said he's not so sure and thinks it's wiser to treat the pandemic as an ongoing war.

The coronavirus has the ability to mutate in ways beyond altering its spike proteins to evade new vaccines, which could make it a fierce adversary for a long time, he said.

On a positive note, there now are drugs such as Paxlovid that greatly decrease the chance of hospitalization and death if they're administered in the early stages of COVID-19, Bradfute said.

"We have more in our toolbox than we did even a year ago," he said.