'Immune-evading' BA.5 subvariant now accounts for 65% of U.S. COVID cases
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Top U.S. health officials warned Tuesday that a surge of COVID-19 cases driven by the highly transmissible Omicron subvariant BA.5 has arrived, but stressed that the country has the tools — like vaccines and antiviral treatments — to prevent people from getting seriously ill.
“We know how to manage it,” Dr. Ashish Jha, coordinator of the White House’s COVID-19 response, said at a virtual press briefing. “We can prevent serious illness. We can save lives and we can minimize disruptions caused by COVID-19.”
According to the Centers for Disease Control and Prevention, the BA.5 subvariant now accounts for 65% of current COVID-19 cases in the United States.
Dr. Anthony Fauci, the nation’s top infectious disease expert and chief medical adviser to President Biden, said that BA.5 “substantially evades neutralizing antibodies” induced in people who have been vaccinated or previously infected.
But Fauci said that the current vaccines are “still effective at preventing severe COVID-19 outcomes” such as hospitalization and death — and urged Americans to stay up to date with their COVID shots.
“The threat to you is now,” he said. “If you are not vaccinated to the fullest ... then you’re putting yourself at an increased risk that you can mitigate against by getting vaccinated.”
The warnings Tuesday from Fauci and other top COVID officials come as the U.S. transitions into what experts describe as a new phase of the pandemic.
Call it the Age of Reinfection.
“BA.5 puts the nail in the coffin of the myth that the virus will evolve into a milder form and fade away,” Dr. Eric Topol, founder of the Scripps Research Translational Institute, wrote Tuesday in the Los Angeles Times. “We could easily see more variants — indeed a whole new family with more extensive immune evasion and growth advantage — in the months ahead.”
At first, COVID-19 seemed like a one-and-done infection. Not anymore. The primary culprit is BA.5, which has a bevy of mutations that make it better than any of its predecessors at dodging whatever immune defenses we’ve built up over two and a half years of infection and vaccination, then infecting us anyway.
BA.5 isn’t the first evasive variant we’ve encountered; both Delta and the earlier versions of Omicron also sidestepped first-generation antibodies. But BA.5 and its closely related cousin, BA.4, are unique because they evolved specifically to elude the massive amounts of fresh immunity left behind by the original iteration of Omicron after it swept the world last winter — meaning that the old assumptions about a recent infection completely shielding you from rapid reinfection no longer apply.
“We do know [BA.5] to be more transmissible and more immune-evading,” CDC Director Rochelle Walensky said at Tuesday’s briefing. “People with prior infection, even with BA.1 or BA.2, are likely still at risk for BA.4 and BA.5.”
None of this will set the U.S. back to square one. Despite elevated case levels, there are now fewer U.S. COVID patients in intensive care units than there were during previous phases of the pandemic, and the national death rate (about 300 to 400 per day) is near the all-time low. Acquired immunity, multiple rounds of vaccination and improved treatment options are helping — a lot.
“Even in the face of BA.5, the tools we have continue to work,” Jha said Tuesday, noting the importance of boosters for those over 50 and postinfection treatments such as Paxlovid.
But to our immune system, the distance from BA.1 to heavily mutated BA.5 is “far greater” than the distance between the original SARS-CoV-2 virus and previous blockbuster variants such as Alpha and Delta — which does make it harder to recognize and respond to. According to the latest research, that could mean:
More breakthrough infections, especially among people who previously had BA.1. Compared to BA.2, BA.2.12.1 is only modestly (1.8-fold) more resistant to antibodies from vaccinated and boosted individuals. But BA.4 and BA.5 are substantially (4.2-fold) more resistant.
More symptoms. BA.4 and BA.5 are also better at replicating in lung cells than BA.2 — a shift that might signal, according to one experimental model, that they’re more “pathogenic” as well (that is, more likely to make you sick). A new report from the highly regarded Kirby Institute in Australia also suggests that the “infectivity” of BA.5 — its ability to get into cells and make copies of itself — is more like Delta than like prior versions of Omicron.
More resistance to treatments. At the same time, BA.4 and BA.5 appear to be 20-fold more resistant than BA.2 to Evusheld — an important monoclonal antibody treatment that has been providing preemptive protection for immunocompromised people.
So far, the rise of BA.5 in the U.S. has coincided with the decline of earlier versions of Omicron, leading to what appears to be a plateau in nationwide case counts of around 100,000 per day. (The vast majority of infections are now going unreported as Americans increasingly rely on rapid home tests rather than the PCR tests used earlier in the pandemic.) But reinfections have doubled in recent weeks in places like San Diego County, Calif., and test positivity, hospitalizations and even ICU admissions have been steadily increasing across the country. Experts worry that the virus’s accelerating evolution and aggressive new trajectory — toward greater transmissibility, evasiveness and possibly pathogenicity — could endanger vulnerable Americans in the months ahead.
According to CDC data, 67% of the U.S. population is considered fully vaccinated, having received the first two doses of Pfizer or Moderna’s COVID-19 vaccines or the single-dose Johnson & Johnson COVID shot. But less than half of those eligible for boosters (47%) have gotten one, and a new booster targeted to BA.5 isn’t expected until October at the earliest.
“It’s very, very clear ... that immunity wanes, whether that’s immunity following infection or immunity following vaccination,” Fauci said Tuesday. “If you were infected with BA.1, you really don’t have good protection against [infection with] BA.5.”
And though the daily U.S. death toll is lower than it was earlier in the pandemic, it’s still “too high,” Jha said.
“We are at a stage of the pandemic when most COVID-19 deaths are preventable,” he said.
“Variants will continue to emerge if the virus circulates globally and in this country,” Fauci added. “We should not let it disrupt our lives, but we cannot deny that it is a reality that we need to deal with.”
To that end, Jha said that the administration would be releasing two reports on “long COVID” in early August, followed by a strategy to speed the development of next-generation vaccines that can protect against all coronavirus variants and stop infection before it starts.
“You’ll hear more from us in the days and weeks ahead,” Jha said. “It’s something we’ve been working quite assiduously on.”
