When Will the BA.5 Wave End?

Masked and unmasked commuters at Union Station in Los Angeles on July 12. Photo: Irfan Khan/Los Angeles Times via Getty Images

On Friday, the Biden administration renewed the nation’s COVID-19 public-health emergency through at least mid-October. The extension comes amid America’s second-largest COVID wave, fueled by the shifty, ultra-transmissible BA.5 subvariant, which is still causing countless new infections and reinfections across the country. Unfortunately, the number of hospitalizations is now also on the rise — up by around 20 percent over the last two weeks, with a corresponding increase in the number of COVID-positive ICU patients. Last week, the CDC forecasted that COVID hospital admissions would increase more than fourfold by August 5.

The number of daily COVID deaths in the country has also ticked up; an average of more than 400 people are now dying with COVID every day, up from a post-Omicron wave low of 264 in early June — though still nowhere near the average of more than 2,600 daily deaths during the peak of the Omicron wave. Hospital COVID metrics are also a fraction of earlier pandemic peaks.

Thus far against BA.5 and its fellow Omicron subvariants, the U.S. has avoided severe outcomes commensurate with previous waves, which is definitely a good thing. That’s a direct result of people getting vaccinated, the remarkable wall of immunity vaccination and prior infections have helped us build, and doctors having their largest-ever collection of tools to fight off severe COVID.

At the same time, while most Americans’ immune systems appear to be holding up well against severe illness from BA.5, the subvariant remains a unique and worrisome threat that scientists are still working to fully understand. A large percentage of Americans don’t have as much protection against the strain as they could: Much of the population remains under-vaccinated; immunity may be waning for some; BA.5 is naturally way better at evading that immunity in the first place; and a lot of Americans, including many policymakers, have thrown virtually all pandemic precaution to the wind. In addition, the long-term implications of repeat reinfection remain unclear — particularly with respect to long COVID. And as always, based on how the Omicron era has played out thus far, BA.5 may be just a taste of what’s to come.

This subvariant and apathy-fueled dynamic of widespread, effectively unmitigated infection and reinfection may end up playing out like both a wave and a flood, with surges that never fully recede amid a high baseline of community spread. As Katherine J. Wu wrote at The Atlantic last week, “this lofty mesa is a disconcerting place to be” — and there’s no end in sight:

The subvariants keep coming. Immunity is solid against severe disease, but porous to infection and the resulting chaos. Some people are getting the virus for the first time, others for the second, third, or more, occasionally just weeks apart. And we could remain at this elevation for some time. … More variants mean more infections; more infections mean more variants. It’s true that, compared with earlier in the pandemic, hospitalization and death rates remain relatively low. But a high rate of infections is keeping us in the vicious viral-evolution cycle. “The main thing is really this unchecked transmission,” says Helen Chu, an epidemiologist and vaccine expert at the University of Washington. We might be ready to get back to normal and forget the virus exists. But without doing something about infection, we can’t slow the COVID treadmill we’ve found ourselves on.

For now, BA.5 continues to assert dominance over its predecessors. It made up 65 percent of all U.S. COVID cases a week ago, according to the latest update to the CDC’s Nowcast model, and it’s continuing to spread. The CDC estimates that 93 percent of U.S. counties are experiencing high community transmission. Most of it is unrestrained.

Unfortunately, none of the available COVID metrics offers a complete view of how big the wave is. Average test positivity is one window: A rate of 10 percent is considered high; the seven-day average test-positivity rate in the country now remains above 17 percent, and in many states the rate appears to be much higher.

Average COVID test positivity rate in the U.S. through July 14, according to the New York Times dashboard. Illustration: Screencap/The New York Times

According to the CDC’s COVID community level ratings, which factor in reported cases and hospital capacity, 55 percent of Americans now live in high-risk communities where they should be masking up again — up 32 percent from the previous week. (All of New York City, along with most of the downstate region, are currently rated high risk by that metric as well.) Now that unreported at-home rapid testing is the new normal, official case counts are an antiquated metric, so it’s impossible to know how many cases there actually are nationwide. There may be as many as 300,000 to 500,000 Americans getting newly infected or reinfected every day, Dr. Anthony Fauci said last week. The wave is clearly visible in COVID wastewater data too:

U.S. COVID-19 wastewater levels through July 13, according to data collected by Biobot Analytics. Photo: Screencap/Biobot Analytics

The surge of cases in California’s Los Angeles County, which is the state and nation’s most populous county, may trigger the return of an indoor mask mandate if COVID conditions don’t improve in less than two weeks. Overall, L.A. County provides a useful look-in on the state of the BA.5 wave. The number of COVID deaths there has doubled since mid-June, to about 100 deaths a week. That’s the highest the county’s weekly death toll has been since early April, and about a fifth of what the toll was at the height of the winter Omicron wave. Over the last month, the number of people hospitalized with COVID in the county has more than doubled, to 1,252 patients as of July 15, including 116 people in intensive care, which is nearly 80 percent higher than a month prior. In addition, as the Los Angeles Times reported last week:

Only about 42 percent of L.A. County’s hospitalized coronavirus-positive patients are admitted specifically for COVID-19 illness — as opposed to incidentally testing positive while being in the hospital for other reasons. But officials have also noted a recent increase in the share of coronavirus-related visits to emergency departments. Two months ago, 5 percent of emergency room visits were coronavirus-related; now it’s close to 10 percent.

The potential return of Los Angeles County’s indoor mask mandate is linked to the CDC’s community level framework, which is itself primarily linked to hospitals’ capacity for handling COVID patients. If the county’s community level is “high” for two consecutive weeks, the mask mandate is automatically reinstated; it rose to that level on Thursday. If the community level doesn’t go back down by July 28, the countywide mandate will be reinstated on July 29. According to California’s projections, the Times notes, COVID hospitalizations may begin to decline around that time instead.

Many COVID experts have criticized the CDC’s community level framework for not sufficiently reflecting and communicating the risk of catching COVID. The CDC’s community transmission framework, on the other hand, is now primarily based on counties’ test-positivity rates. From the vantage point of test positivity, L.A. County’s rising COVID wave has been apparent for well over a month, and the rate has been higher than 10 percent for more than three weeks.

In addition to L.A. County’s COVID hospitalizations and deaths trending up, the wave has been hitting workplaces hard. The Los Angeles Times reports that the number of workplaces reporting clusters of cases (i.e., three or more cases within a 14-day period) has nearly quadrupled since May, and there has been a steep spike this month — up to 371 workplaces during the week ending July 12. The workplaces reporting clusters include airports, food-processing companies, retailers, aerospace companies, and film and television production studios, among others.

County officials were also investigating potential clusters, mostly of 15 cases or more, at more than 40 nursing homes over the past week. The percentage of overall COVID deaths made up by the county’s nursing-home residents has been steadily rising as well.

Airports and nursing homes are two of the only workplaces still subject to an indoor mask mandate in the county. Mask mandates are no silver bullet, particularly at a time when much of the public has largely abandoned COVID precautions and may simply ignore the mandate. But tightly fit high-filtration face masks like N95s remain one of the best ways to prevent catching or spreading COVID in any environment. Like in countless other places around the U.S., public-health officials in L.A. County have been strongly recommending wearing masks in indoor public spaces for a while, but “virtually nobody did it,” a county supervisor commented last week. There’s no question a mask mandate would have a much larger impact, but county officials don’t believe one is necessary until the wave appears to be threatening hospitals.

Hopefully, California’s projections are correct and the state’s BA.5 hospitalization surge will have peaked by the beginning of August. On Thursday, nine other U.S. counties with populations of more than 1 million people were moved into the high-risk category per the CDC’s community level ratings. How they and the rest of the country fares — and how and when this wave may end — remains to be seen.

When Will the BA.5 Wave End?