COVID-19 Data Dispatch

Tag: BA.4.6

  • The Omicron subvariants start coming and they don’t stop coming

    The Omicron subvariants start coming and they don’t stop coming

    A veritable alphabet soup of subvariants. Chart from the CDC, data as of October 15.

    When the CDC updated its variant prevalence estimates this week, the agency added new versions of Omicron to the dashboard. In the U.S., COVID-19 cases are now driven by: BA.5, BA.4.6, BQ.1, BQ.1.1, BF.7, BA.2.75, and BA.2.75.2. And possibly more subvariants that we aren’t tracking yet.

    As evolutionary biology expert T. Ryan Gregory pointed out on Twitter recently, Omicron’s evolution is “off the chart.” 

    Or, to parody Smash Mouth: the Omicron variants start coming and they don’t stop coming and they don’t stop coming and they don’t stop coming…

    Let’s go over the veritable alphabet soup of variants we’re dealing with right now, as well as one newer variant identified in east Asia that experts are closely watching.

    BA.5, BA.4, BA.4.6

    BA.5 is currently the dominant Omicron lineage in the U.S., causing about two-thirds of new COVID-19 cases in the week ending October 15. Along with BA.4, BA.5 split off from the original Omicron lineage and was first identified by South African scientists over the summer.

    As these two subvariants spread around the world, it quickly became clear that they could spread faster than other versions of Omicron and reinfect people who’d previously gotten sick with those prior lineages. For more details, see this post from June. BA.5 later pulled out from BA.4 as the most competitive lineage.

    BA.4.6 evolved out of BA.4. It appears to have a small advantage over BA.5, but can’t really compete with the newer subvariants we’re seeing now; according to the CDC’s estimates, it’s been causing around 10% to 12% of new cases nationwide for the last few weeks (without much growth).

    BQ.1 and BQ.1.1

    BQ.1 and its descendant BQ.1.1 are the two newest subvariants to show up in the CDC’s prevalence estimates, both causing about 5.7% of new cases nationwide in the last week. They actually evolved out of BA.5: BQ.1 is shorthand for a much longer, more unwieldy variant name that nobody wants to type out on Twitter.

    In the U.S., BQ.1 and BQ.1.1 are starting to outcompete their parent lineage, BA.5. They’ve grown from causing less than 1% of new cases to over 10% of new cases in the last month. These subvariants are also now outcompeting other strains in the U.K. and other European countries.

    As CBS News’s Alexander Tin explains, health experts are concerned that COVID-19 treatments like monoclonal antibodies might work less well against BQ.1 and BQ.1.1. We don’t have clear data on this yet, but pharmaceutical companies will test out the newer variants in the weeks to come. The Omicron bivalent boosters, at least, are expected to continue working against this lineage.

    BF.7

    BF.7 is another offshoot of BA.5 (again, this is shorthand for a longer name). I dedicated a post to it in late September, and the subvariant’s position hasn’t changed significantly since then: it seems to be a bit more transmissible than BA.5, but not so much that it is quickly outcompeting the parent lineage. BF.7 caused about 5% of new cases nationwide in the last week.

    Similarly to BQ.1 and BQ.1.1, there are some concerns that COVID-19 treatments will be less effective against BF.7 than other versions of Omicron based on the subvariant’s spike protein mutations, but we do not have clinical data at this point.

    BA.2.75 and BA.2.75.2

    BA.2.75, as you might guess from the notation, evolved out of BA.2—the same original Omicron lineage that produced BA.2.12.1 and drove surges in places like New York City over the summer. It has also remained present at fairly low levels across the U.S. recently, causing just 1.3% of new cases in the last week, according to the CDC’s estimates.

    But BA.2.75 now has its own offshoot, called BA.2.75.2, that appears to be a bit more competitive. The CDC recently started splitting BA.2.75.2 out of its parent lineage in its prevalence estimates, showing that it’s growing a bit faster (from 0.4% to 1.4% in the last month). Of course, this growth rate pales in comparison to what we’re seeing from the BA.5 sublineages described above.

    XBB

    XBB is the latest international subvariant of concern, identified this week in several east Asian countries. It has spread particularly quickly in Singapore, as described in this article by David Axe at the Daily Beast.

    Like BA.2.75, XBB descended from Omicron BA.2—though it’s gone through more rounds of spike protein mutation; this is why experts are calling it XBB, rather than a long string attached to BA.2. Data so far indicate its growth advantage over BA.5 is similar to what we’re seeing from BQ.1.1. XBB has also raised concerns about treatment and vaccine efficacy, since the bivalent boosters were developed from BA.4 and BA.5. 

    The CDC and other health agencies have yet to identify XBB in the U.S.; experts are closely watching how this new subvariant might be able to compete with our current variations on BA.5.

    Overall takeaways

    Overall, both in the U.S. and around the world, we’re seeing a lot of competition between these subvariants. All of them have small growth advantages over BA.5—which is currently dominant in the U.S.—but none are so different that they’re completely pulling ahead.

    As I wrote last weekend, many experts are anticipating a surge this fall and winter, driven by both new subvariants and less-cautious beavior. We likely won’t see a huge spike at the level of last winter’s massive Omicron surge, but this season will still have plenty of infections (and reinfections).

    We will need more data on how all these newer variants respond to vaccines and treatments, especially the antiviral Paxlovid. But it’s at least promising that many of the circulating variants right now evolved from BA.5, against which our bivalent boosters were specifically designed. It’s a great time to get that booster!

    More variant data

  • National numbers, September 18

    National numbers, September 18

    Wastewater trends in the past couple of weeks are looking a bit messy, with a potential new surge in the Northeast and plateaus in other regions. Chart via Biobot, retrieved on September 18.

    In the past week (September 10 through 16), the U.S. reported about 420,000 new COVID-19 cases, according to the CDC. This amounts to:

    • An average of 60,000 new cases each day
    • 128 total new cases for every 100,000 Americans
    • 16% fewer new cases than last week (September 3-9)

    In the past week, the U.S. also reported about 31,000 new COVID-19 patients admitted to hospitals. This amounts to:

    • An average of 4,400 new admissions each day
    • 9.3 total admissions for every 100,000 Americans
    • 6% fewer new admissions than last week

    Additionally, the U.S. reported:

    • 2,500 new COVID-19 deaths (0.8 for every 100,000 people)
    • 85% of new cases are caused by Omicron BA.5; 10% by BA.4.6; 1% by BA.2.75 (as of September 17)
    • An average of 25,000 vaccinations per day (per Bloomberg)

    Officially-reported COVID-19 cases are still on the decline nationwide this week, as are newly hospitalized patients (a more reliable metric). About 4,400 people with COVID-19 were admitted to hospitals across the country, compared to over 6,000 a day in late July.

    These declines may be short-lived, as reopened schools and increased indoor gatherings contribute to new outbreaks this fall. Last week, I warned that Biobot’s wastewater data showed a slight uptick in coronavirus levels across the country; this week’s update shows a continued increase in the Northeast while other regions are in plateaus.

    Will the Northeast be the first region to experience a new surge again? It seems feasible, based on data from both Biobot and the CDC—though this region also has better wastewater surveillance coverage than other parts of the country, ABC News reporter Arielle Mitropoulos points out. Boston, one long-running wastewater surveillance location, is reporting high coronavirus concentrations at a level not observed since earlier in the summer.

    Nationwide, BA.5 continues to be the dominant variant, causing about 85% of new cases in the week ending September 17 per CDC estimates. But it’s facing competition from newer Omicron subvariants, including BA.4.6 (10% of new cases this week), BA.2.75 (1.3% of cases), and BF.7 (1.7% of cases). As of this week, the CDC is now reporting BA.2.75 and BF.7 separately rather than combining them with other lineages.

    BA.2.75, also called Centaurus, is a subvariant from BA.2 that evolved some additional mutations. BF.7 actually evolved from BA.5; its longer name is BA.5.2.1.X. There hasn’t been much reporting yet on BF.7, but it appears to be present in the Northeast—particularly in New England—at higher levels than in other regions. (Possibly another driver of a new surge in this area.)

    Overall, while COVID-19 spread in the U.S. is occurring less right now than it did earlier in the summer, the risk of encountering this virus is still pretty high across the country. According to the CDC’s “Community Transmission Level” guidance (pre-February), more than 90% of U.S. counties should require masks indoors.

    Instead, we have no masking requirements, increasingly-limited testing, and a booster shot campaign that many Americans do not even know is happening. Between 300 and 400 Americans still die of COVID-19 every day—a number that should be unacceptable—and I fear this number will only go up as we head into winter.

    more national numbers
  • National numbers, September 11

    National numbers, September 11

    A week after new COVID-19 boosters were authorized, the U.S. has yet to see a significant jump in vaccine doses administered. Chart via the CDC.

    In the past week (September 3 through 9), the U.S. reported about 500,000 new COVID-19 cases, according to the CDC. This amounts to:

    • An average of 70,000 new cases each day
    • 150 total new cases for every 100,000 Americans
    • 19% fewer new cases than last week (August 27-September 2)

    In the past week, the U.S. also reported about 32,000 new COVID-19 patients admitted to hospitals. This amounts to:

    • An average of 4,600 new admissions each day
    • 9.9 total admissions for every 100,000 Americans
    • 11% fewer new admissions than last week

    Additionally, the U.S. reported:

    • 2,200 new COVID-19 deaths (0.7 for every 100,000 people)
    • 88% of new cases are caused by Omicron BA.5; 9% by BA.4.6 (as of September 10)
    • An average of 25,000 vaccinations per day (per Bloomberg)

    It might appear that the U.S. reported a significant drop in COVID-19 cases last week, as the CDC’s numbers dropped to about 70,000 new cases a day last week from 87,000 new cases a day in the prior week. But in fact, the decline was likely exaggerated by Labor Day weekend, as testing labs and the public health workers who crunch data took time off.

    Wastewater data from the last two weeks tell a different story. In Biobot’s most recent update, the company reported a slight increase in coronavirus concentration in wastewater at the national level. Regionally, the virus grew in the Northeast, Midwest, and South.

    While hospital admissions and other healthcare system metrics continue to show a decline, wastewater data is often an advanced indicator for new coronavirus surges. In this case, it could mean the often-predicted fall wave is beginning in some parts of the country. Remember: wastewater surveillance can catch transmission upticks early because it doesn’t rely on individuals getting PCR tests or seeking out healthcare—factors that can cause lags and undercounting in case and hospitalization data.

    Potential factors contributing to increased COVID-19 outbreaks might include holiday gatherings and travel, the start of the school year, and new Omicron subvariants taking over. BA.4.6, the lineage from BA.4 that may be even more transmissible, went from causing about 8% of new cases in the week ending September 3 to 9% in the week ending September 10, according to CDC estimates; meanwhile, BA.5’s prevalence dropped by about 1%.

    This might seem like a small shift, but it is an indicator of BA.4.6’s capacity to eventually outcompete BA.5—and reinfect people who previously caught a different version of Omicron. BA.4.6 is causing a higher share of cases in the Midwest, specifically in Iowa, Kansas, Missouri, and Nebraska, so those are states to particularly watch for increased COVID-19 spread.

    At the same time, the CDC reports that 1% of cases nationwide were caused by BA.2 lineages (not BA.2.12.1) last week. This is likely the work of BA.2.75, another subvariant of concern that the CDC isn’t yet tracking separately. (More on that later in the issue.)

    The federal government’s main action to mitigate this probably-coming surge is a new booster campaign, with the Omicron BA.4/BA.5 shots authorized last week. But vaccination numbers have been low so far, with far fewer than 100,000 doses administered each day last week.

    more national numbers
  • Sources and updates, September 4

    Sources and updates, September 4

    Omicron BA.4.6, a newer version of BA.4, is currently more prevalent in the Midwest than other regions of the country. Chart via the CDC, retrieved September 4.
    • Slow rise of BA.4.6 is worth watching: As I mentioned in today’s National Numbers post, a newer subvariant labeled BA.4.6 is gaining ground over other versions of Omicron in the U.S. BA.4.6 evolved from BA.4, and has an additional mutation in the virus’ spike protein that enables it to bypass protection from prior infections. It’s unclear whether BA.4.6 will be able to fully outcompete BA.5, which is currently causing the vast majority of U.S. COVID-19 cases—these two strains are similar enough that the competition may go slowly. So far, the subvariant has been more prevalent in the Midwest than other regions of the country, according to CDC data. Also worth watching: BA.2.75, a subvariant that is dominating some European countries but hasn’t shown up significantly in the U.S. yet.
    • Up to 4 million people may be out of work due to Long COVID: Last week, policy research organization the Brookings Institute published a new report discussing the massive impacts Long COVID is having on America’s labor force. The report utilizes recent data from the Household Pulse Survey (released in June) estimating Long COVID prevalence, in conjunction with research on how many long-haulers might be out of work due to their condition. The results: between two and four million Americans potentially lost their jobs (or are working significantly less) due to Long COVID, costing at least $170 billion a year in lost wages. Even the low ends of these estimates are staggering.
    • U.S. life expectancy declined again in 2021: Americans born in 2021 may expect to live for 76 years on average, according to the CDC’s National Vital Statistics System. This is the lowest life expectancy has been since 1996. CDC researchers attribute the sharp decline in the last two years to the pandemic and drug overdose deaths. Disparities in life expectancy have also increased: Native Americans born in 2021 may expect to live only 65 years on average and Black Americans may expect to live 71 years, compared to 76 years for white Americans.
    • Biobot expands wastewater surveillance for opioid tracking: In the last couple of months, we’ve seen wastewater used to track monkeypox and polio, in addition to COVID-19—suggesting the technology’s capacity for broader public health surveillance. This week, leading wastewater company Biobot announced a new initiative to track opioid use and other high-risk substance use through a similar platform to its current COVID-19 efforts. Tracking the opioid crisis was actually the original focus for Biobot’s founders pre-pandemic, so it’s notable to see the company expanding in this direction now.
    • New technical report on monkeypox outbreak: Speaking of monkeypox, the CDC recently released a detailed report on how the disease has spread through the U.S. and other countries. It’s a new reporting format for the CDC, with the agency releasing data more rapidly than it might have in a scientific study—possibly emulating the U.K. Health Security Agency’s Technical Briefings. Notably, the CDC Center for Forecasting and Outbreak Analytics, the agency’s new modeling center, was a key contributor to the report. Former CFA leader Caitlin Rivers shared key findings from the report here. (And for more on CFA, see this story I wrote for FiveThirtyEight in June.)

    All featured sources