COVID-19 Data Dispatch

Tag: xbb.1.9.1

  • National numbers, August 6

    National numbers, August 6

    Test positivity is way up in the U.S., while hospitalizations are starting to follow this trend. Chart via the CDC.

    During the most recent week of data available (July 16 through 22), the U.S. reported about 8,000 new COVID-19 patients admitted to hospitals, according to the CDC. This amounts to:

    • An average of 1,150 new admissions each day
    • 2.4 total admissions for every 100,000 Americans
    • 12% more new admissions than the prior week (July 9-15)

    Additionally, the U.S. reported:

    • 8.9% of tests in the CDC’s surveillance network came back positive
    • A 10% higher concentration of SARS-CoV-2 in wastewater than last week (as of August 2, per Biobot’s dashboard)
    • 31% of new cases are caused by Omicron XBB.1.6; 17% by EG.5; 11% by XBB.2.3; 10% by XBB.1.9 (as of August 5)

    Over the last few weeks, the signals of a summer COVID-19 surge in the U.S. have grown steadily clearer. Viral levels in wastewater, test positivity, and hospitalizations are all climbing across the country.

    Wastewater surveillance data from Biobot suggest that coronavirus levels have doubled nationally in the last month. The surge is impacting all major regions of the country; the Northeast and South saw earlier increases, but the Midwest and West Coast are now catching up.

    The CDC’s wastewater surveillance network also points to increasing COVID-19 spread, with sites across the country reporting higher viral levels. While wastewater surveillance remains uneven (some states are testing in every county, others in just a handful of locations), it still gives us enough information to identify a widespread surge.

    Test positivity from the CDC’s lab testing network shows continued increases as well. About 8.9% of COVID-19 tests reported to the agency returned positive results in the week ending July 29, compared to 4.5% in the week ending June 24. This increase, too, is consistent across regions.

    Hospitalizations for COVID-19 are also going up, according to the CDC. These data are significantly delayed, with the most recent numbers dating to about two weeks ago. So, while overall patient numbers remain low right now, I expect they will continue to rise as the surge goes on.

    The coronavirus’ continued evolution is likely playing a role in this summer’s increased spread, as are summer travel and waning immunity from past vaccinations. Omicron EG.5, a descendant of the XBB.1.9 lineage, is the latest variant to spread widely, according to the CDC’s estimates.

    No one version of XBB has yet shown a significant ability to spread much faster or cause more severe symptoms than other variants. Rather, many iterations of this Omicron lineage are spreading in tandem, continuing to mutate with every infection. And with fewer PCR tests happening, it’s harder for health agencies to keep track.

    This summer’s surge may be less visible than ever. But wastewater data suggest we’re seeing similar levels of COVID-19 spread as we saw with Delta in summer 2021. Precautions are still important!

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  • National numbers, July 23

    National numbers, July 23

    A wide variety of XBB-related Omicron variants are competing across the U.S. Data from the CDC, as of July 22.

    During the most recent week of data available (July 2 through 8), the U.S. reported about 6,200 new COVID-19 patients admitted to hospitals, according to the CDC. This amounts to:

    • An average of 900 new admissions each day
    • 1.9 total admissions for every 100,000 Americans
    • 1% fewer new admissions than the prior week (June 25-July 1)

    Additionally, the U.S. reported:

    • 6.3% of tests in the CDC’s surveillance network came back positive
    • A 9% higher concentration of SARS-CoV-2 in wastewater than last week (as of July 19, per Biobot’s dashboard)
    • 24% of new cases are caused by Omicron XBB.1.6; 19% by XBB.1.9; 13% by XBB.2.3 (as of July 22)

    COVID-19 data in the U.S. is showing increasingly clear signs of a summer surge, with infections rising across the country. However, thanks to the federal public health emergency’s end, we have less and less data to track this trend.

    Wastewater data from Biobot Analytics show that national coronavirus levels have gone up by about 68% in the last month. Current levels are far below this time last year (when the Omicron BA.4/BA.5 surge was in full swing), but still at their highest in several months.

    Biobot’s regional data suggest that the COVID-19 uptick is hitting all major regions. But the increases have been most pronounced in the Northeast and South; coronavirus levels have doubled in both regions in the last month, per Biobot.

    The CDC’s wastewater surveillance network has picked up these increases as well, with more than half of testing sites in this network (with recent data) reporting coronavirus upticks in the last two weeks. Some major cities, such as Boston and Los Angeles, are also reflecting the increase.

    Test positivity data from the CDC also show the increasing COVID-19 spread: nationally, test positivity from the labs in the agency’s surveillance network has gone up from 4.3% one month ago to 6.3% in the most recent week of data. The most prominent increases for this metric are similarly in the Northeast and South, and in the health region including Oregon, Washington, Idaho, and Alaska.

    One metric not yet showing an increase is the CDC’s hospital admissions data. But the agency has continued to report these data with a lag: as of today, the most recent hospitalization numbers are as of July 8, two weeks ago. The CDC has yet to provide a clear explanation for this reporting lag.

    Either way, the data we do have give us sufficient warnings about this summer’s uptick in COVID-19 spread. One likely culprit is the continued evolution of Omicron XBB: about 15 different subvariants are currently competing, according to the CDC’s latest data. No variant seems to be a clear winner yet.

    Regardless of which variant comes to dominate next, the same safety measures continue to work against COVID-19.

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  • National numbers, July 16

    National numbers, July 16

    Wastewater surveillance data from Biobot indicate that three out of four major U.S. regions are experiencing increased COVID-19 spread.

    In the past week (July 2 through 8), the CDC did not update COVID-19 hospitalization data for unclear reasons. During the most recent week of data available (June 25 through July 1), the U.S. reported about 6,200 new COVID-19 patients admitted to hospitals, according to the CDC. This amounts to:

    • An average of 900 new admissions each day
    • 1.9 total admissions for every 100,000 Americans
    • 1% fewer new admissions than the prior week (June 18-24)

    Additionally, the U.S. reported:

    • 5.5% of tests in the CDC’s surveillance network came back positive
    • A 13% higher concentration of SARS-CoV-2 in wastewater than last week (as of July 12, per Biobot’s dashboard)
    • 32% of new cases are caused by Omicron XBB.1.6; 15% by XBB.1.9; 13% by XBB.2.3 (as of July 8)

    National COVID-19 data are showing signs of a summer uptick in infections across multiple regions. Newer variants, summer travel, and holidays are likely contributing to this increase, though it’s hard to say if we will see a real surge or a continued shifting of the U.S.’s high COVID-19 baseline.

    Wastewater surveillance data from Biobot Analytics show a significant uptick in coronavirus levels over the last month, with an increase of about 50% from June 14 to July 12. Three out of four major U.S. regions (the Northeast, South, and West Coast) report notable increases, while the Midwest reports a slower uptick.

    The CDC’s National Wastewater Surveillance System (NWSS) is not yet showing a pronounced increase. Of the testing sites in this network that reported data in the last two weeks, about half reported upticks while the others reported declines or plateaus. However, NWSS data tend to be updated on a more delayed schedule than Biobot’s dashboard, since the CDC compiles information from a number of state and local health agencies.

    As epidemiologist Caitlin Rivers points out in her Substack post describing the wastewater trend, COVID-19 summer waves in the U.S. tend to start in the South. Some experts attribute this to more indoor summer activities in the region, but there’s little data to back this up, Rivers writes. Plus, this year, the summer uptick has appeared to start in multiple regions of the country at the same time.

    In addition to the wastewater data, test positivity data from the CDCs National Respiratory and Enteric Virus Surveillance System (NREVSS) show a similar uptick in the last month: from 4.1% of COVID-19 tests returning positive results in the week ending June 10 to 5.5% in the week ending July 8. Remember, this NREVSS doesn’t share data from all PCR tests done in the U.S. (as the CDC no longer has authority to collect this information); but it is set up to provide national and regional estimates.

    According to NREVSS, COVID-19 test positivity is going up in several major regions, including New York and New Jersey, the Mid-Atlantic, the South, the Gulf Coast, and the Northwest. All of these regions are dealing with the Omicron XBB variant’s continued evolution; in the CDC’s most recent variant update on July 8, the agency listed 12 different XBB subvariants competing for hosts.

    The CDC failed to update its COVID-19 hospitalization data this week, so the most recent available data are from the week ending July 1. Typically, the agency’s data scientists will add notes to their dashboard explaining update delays or errors, but this week, I couldn’t find anything.

    As I wrote on June 25: sometimes, I wonder if the CDC doesn’t think anyone is checking their dashboard anymore. But we are! COVID-19 data may be more limited than ever, but we still have enough information to know when cases are ticking up again—and we know the measures needed to protect ourselves and our communities.

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  • National numbers, June 11

    National numbers, June 11

    Some NYC sewershed have reported substantial increases in coronavirus levels in recent weeks. Screenshot from the New York State wastewater dashboard.

    In the past week (May 28 through June 3), the U.S. reported about 7,200 new COVID-19 patients admitted to hospitals, according to the CDC. This amounts to:

    • An average of 1,000 new admissions each day
    • 2.2 total admissions for every 100,000 Americans
    • 6% fewer new admissions than last week (May 21-27)

    Additionally, the U.S. reported:

    • 4.2% of tests in the CDC’s surveillance network came back positive (an 8% decrease from last week)
    • 40% of new cases are caused by Omicron XBB.1.5; 26% by XBB.1.16; 21% by XBB.1.9 (as of June 10)
    • (Biobot update delayed)

    Nationally, the COVID-19 situation in the U.S. is similar to where we’ve been for the last few weeks. Major metrics (such as we have them) show an overall plateau in disease spread. Wastewater trends in a few places suggest a summer surge might be coming, but it’s hard to say for sure.

    Hospital admissions and test positivity (from the specific network of labs reporting to the CDC) are trending slightly down at the national level. But there are still about 1,000 people being hospitalized with COVID-19 every day.

    Biobot Analytics, my usual go-to source for wastewater surveillance data, did not update their dashboard this week due to a tech issue. The company’s most recent data, as of May 29, show plateaus in all four major regions.

    The CDC’s National Wastewater Surveillance System (NWSS) shows a similar picture. Among about 1,100 sewage testing sites that recently reported to the CDC, 60% reported decreases in coronavirus levels in the last two weeks while 40% reported increases.

    New York City is one of the places seeing wastewater increases, as I noted last week. Patterns differ somewhat across the city’s fourteen sewersheds, with some reporting more than 1000% increases in wastewater levels in recent weeks while others are still in plateaus.

    Both the New York/New Jersey and New England regions are reporting slight upticks in their test positivity, according to the CDC’s surveillance network. This (along with the trends in NYC’s sewage) could be a precursor of more COVID-19 spread this summer, but it’s currently hard to say for sure.

    The CDC updated its variant estimates (now reported every other week) this past Friday. XBB.1.5 is still the most common lineage, causing an estimated 40% of cases, the CDC reports. XBB.1.16 and XBB.1.9 continue to outcompete it, causing about 26% and 21% of cases respectively.

    These newer lineages have yet to contribute to a significant shift in transmission, from what I can tell. We have yet to see if past immunity in the U.S. can hold off against the ever-evolving Omicron variants this summer.

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  • National numbers, May 28

    National numbers, May 28

    The CDC is now updating its variant estimates every two weeks.

    In the past week (May 14 through 20), the U.S. reported about 8,300 new COVID-19 patients admitted to hospitals, according to the CDC. This amounts to:

    • An average of 1,200 new admissions each day
    • 2.5 total admissions for every 100,000 Americans
    • 11% fewer new admissions than last week (May 7-13)

    Additionally, the U.S. reported:

    • A 16% lower concentration of SARS-CoV-2 in wastewater than last week (as of May 24, per Biobot’s dashboard)
    • 54% of new cases are caused by Omicron XBB.1.5; 19% by XBB.1.16; 18% by XBB.1.9 (as of May 27)

    The COVID-19 plateau continues, with hospital admissions and viral levels in wastewater (the two main metrics I’m looking at these days) both trending slightly down at the national level. Newer Omicron variants are still on the rise, but don’t seem to be impacting transmission much yet.

    Hospitalizations continue to trend slightly down across the board, though hospitals are still reporting more than 1,000 new COVID-19 patients each day. The vast majority of U.S. counties have low hospitalization levels, according to the CDC, with just 14 counties in the medium or high categories.

    Coronavirus levels in wastewater are following a similar pattern: trending down very slightly, continuing the middling plateau of the last couple of months. All four major regions are still in this holding pattern, according to Biobot’s data.

    We have new variant data this week, as the CDC is now on a biweekly schedule for updates. XBB.1.5 caused just over half of new cases in the U.S. in the two weeks ending May 27, as it slowly gets outcompeted by newer versions of Omicron. XBB.1.16 and XBB.1.9 continue to rise, causing 19% and 18% of hew cases respectively.

    XBB.1.16 is most prevalent on the West Coast, the Northeast, and the Gulf Coast states, while XBB.1.9 is most prevalent in the Midwest, according to the CDC—though these estimates are becoming less reliable over time, since so few COVID-19 samples are sequenced.

    The CDC has also recently added national and regional COVID-19 test positivity data back to its dashboard, representing tests conducted by labs in the CDC’s National Respiratory and Enteric Virus Surveillance System.

    Nationally, test positivity is trending down, at just under 5% of COVID-19 tests (in this lab network) returning positive results in the most recent week of data. Test positivity is trending up slightly in the Northeast and New York/New Jersey regions; I’ll be following to see if this continues in the coming weeks.

    Finally, a bit of good news: excess deaths in the U.S. have returned to baseline in the last couple of months. While hundreds are still dying from COVID-19 every day, the excess death trend suggests that the disease is currently not causing a significant ripple effect on overall mortality the way that it did in earlier stages of the pandemic. (Of course, this could change with a new surge.)

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  • National numbers, May 14

    National numbers, May 14

    The CDC and its partners are sequencing far fewer coronavirus samples than they have at prior periods of the pandemic, making it harder to spot new variants of concern.

    In the past week (April 30 through May 6), the U.S. reported about 9,500 new COVID-19 patients admitted to hospitals, according to the CDC. This amounts to:

    • An average of 1,400 new admissions each day
    • 2.9 total admissions for every 100,000 Americans
    • 7% fewer new admissions than last week (April 22-29)

    Additionally, the U.S. reported:

    • A 14% lower concentration of SARS-CoV-2 in wastewater than last week (as of May 10, per Biobot’s dashboard)
    • 64% of new cases are caused by Omicron XBB.1.5; 13% by XBB.1.9; 14% by XBB.1.16 (as of May 13)
    • An average of 70,000 vaccinations per day

    COVID-19 spread continues to trend down in the U.S., though our data for tracking this disease is now worse than ever thanks to the end of the federal public health emergency. If newer Omicron variants cause a surge this summer, those increases will be hard to spot.

    As a result of the PHE’s conclusion this week, the CDC is no longer collecting national case counts or testing data. Instead, the agency now recommends using hospitalization data to monitor how hard COVID-19 is hitting your community—even though this metric typically lags behind actual infection patterns—while variant data and wastewater surveillance may provide warnings about new surges.

    My national updates will take a similar approach. This week, hospital admissions continue their national plateau, with a decrease of about 7% from the week ending April 29 to the week ending May 6. The CDC’s national map show that admissions are low across the country, with 99% of counties reporting fewer than 10 new admissions per 100,000 residents.

    Wastewater surveillance also suggests that, while there’s still a lot of COVID-19 in the U.S., disease spread is still on a plateau or slight decline in most of the country. Biobot’s data show a minor national downturn in recent weeks; trends are similar across the four major regions, though the decline is a bit steeper on the West Coast.

    The variant picture also hasn’t changed much: XBB.1.5 caused about two-thirds of new cases in the last two weeks, according to the CDC’s estimates. XBB.1.6 caused about 14% and XBB.1.9 caused 13%; these newer versions of Omicron are gaining ground, but fairly slowly. Regionally, XBB.1.6 is most prevalent in the Northeast and on the West Coast, while XBB.1.9 is most prevalent in the Midwest.

    It’s worth noting, though, that the CDC has switched its variant reporting from weekly to every other week, as fewer patient specimens are going through sequencing for variant identification. The agency and its surveillance partners are sequencing around 5,000 samples every week, compared to over 80,000 a week at the height of the first Omicron surge.

    Limited sequencing efforts will make it harder for the CDC to quickly identify (and respond to) new variants of concern. The same challenge is happening around the world, as PCR tests become less broadly available. Sequencing coronavirus samples from wastewater may help, but that’s only happening in a small subset of sewage testing sites right now.

    One last bit of good news: vaccine administration numbers are up in the last couple of weeks, as seniors and other eligible high-risk people get their second bivalent boosters. About 70,000 people received vaccines each day this week, compared to around half that number a few weeks ago. If you’re eligible for a second booster, this is a good time to make an appointment!

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  • National numbers, May 7

    National numbers, May 7

    New hospital admission for COVID-19 continue to drop, though they are at higher levels than we’ve seen in past lulls. Chart from the CDC dashboard.

    In the past week (April 27 through May 3), the U.S. officially reported about 77,000 new COVID-19 cases, according to the CDC. This amounts to:

    • An average of 11,000 new cases each day
    • 14% fewer new cases than last week (April 20-26)

    In the past week, the U.S. also reported about 10,000 new COVID-19 patients admitted to hospitals. This amounts to:

    • An average of 1,400 new admissions each day
    • 2.9 total admissions for every 100,000 Americans
    • 10% fewer new admissions than last week

    Additionally, the U.S. reported:

    • 1,100 new COVID-19 deaths (150 per day)
    • 67% of new cases are caused by Omicron XBB.1.5; 13% by XBB.1.9; 13% by XBB.1.16 (as of May 6)
    • An average of 60,000 vaccinations per day

    The national COVID-19 plateau persists. Cases, new hospitalizations, and wastewater surveillance all indicate slight declines (but persistent disease spread) across the country. New variants are on the rise, but have yet to noticeably change these trends.

    New COVID-19 cases declined by about 14% last week compared to the week prior, while hospital admissions declined by 10%. While the case numbers might seem low (just 11,000 reported each day), they are a drastic undercount of true infections, as we can see by comparing total new cases to new hospitalizations.

    This week, the CDC’s reported cases were about eight times the number of new hospital admissions reported by the agency. While this time last year, new cases were 30 times new hospital admissions. In other words, as case reporting gets less accurate, we are still tracking cases with severe sypmtoms (i.e. those that require hospitalization), but missing many of the mild or asymptomatic cases—that could still lead to detrimental outcomes, like Long COVID.

    Wastewater surveillance—which provides population-level data regardless of how many people are getting PCR tests or otherwise seeking healthcare—suggests that the U.S. has been at an overall plateau of COVID-19 spread, but a higher one than we’ve experienced in past lulls (such as in spring 2021, when people were receiving their first vaccine doses).

    Biobot’s national wastewater data shows fairly steady transmission for the last month. The company’s regional data shows a similar picture; the West Coast has slightly higher coronavirus levels than the other three major regions, but is on a decline. A few counties in California and other West states have seen increases recently, but it’s not a sustained pattern across the board.

    Newer versions of the Omicron variant are competing with XBB.1.5, but the transition is happening slowly. XBB.1.5 still caused about two-thirds of new cases in the U.S. last week, according to CDC estimates, while XBB.1.16 and XBB.1.9 both caused about 13% of new cases.

    It’s currently hard to say if the country will face a real surge from XBB.1.16 and XBB.1.9. XBB.1.16 has wreaked some havoc internationally, but it may be similar enough to the variants now circulating in the U.S. that it won’t make a huge dent. Or, if we do see an increase in cases, it could be more like a “mini-wave” of largely-mild infections than a surge that really strains the healthcare system.

    This “mini-wave” idea has been covered by a few news outlets recently, including Nature and the Atlantic. It’s certainly promising that the U.S. hasn’t had a real surge since the winter holidays, now almost six months ago—but we have to remember that any new cases, no matter how low the numbers are, can lead to potential severe symptoms and long-term illness. I, for one, am not letting up my guard on safety.

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  • National numbers, April 30

    National numbers, April 30

    The number of COVID-19 tests reported to the CDC has declined precipitously since peak COVID-19 surges, even though COVID-19 spread has not. Chart from the CDC.

    In the past week (April 20 through 26), the U.S. officially reported about 88,000 new COVID-19 cases, according to the CDC. This amounts to:

    • An average of 13,000 new cases each day
    • 10% fewer new cases than last week (April 13-19)

    In the past week, the U.S. also reported about 11,000 new COVID-19 patients admitted to hospitals. This amounts to:

    • An average of 1,500 new admissions each day
    • 3.2 total admissions for every 100,000 Americans
    • 16% fewer new admissions than last week

    Additionally, the U.S. reported:

    • 1,100 new COVID-19 deaths (150 per day)
    • 69% of new cases are caused by Omicron XBB.1.5; 13% by XBB.1.9; 12% by XBB.1.16 (as of April 29)
    • An average of 40,000 vaccinations per day

    Major COVID-19 metrics continue to suggest an ongoing (though slight) decline in the virus’ spread nationally, despite the rise of newer and more contagious variants. The moderate plateau persists.

    Officially-reported cases and new hospital admissions declined by 10% and 16% respectively last week, compared to the week prior. According to the CDC’s data notes, three states (Florida, Iowa, and Pennsylvania) did not report cases last week, while two states (Louisiana and Indiana) reported extra cases from their historical backlogs.

    In addition to the ongoing reporting issues from state health departments, it’s important to remember that PCR testing continues to decline across the country. About one million PCR and similar lab test results were reported to the CDC last week, compared to peaks over 10 million per week during major surges.

    Still, the hospitalization numbers and wastewater surveillance data lead me to suggest that we really are in a transmission plateau. Wastewater data from Biobot show a slight decline in national coronavirus concentrations over the last month.

    All four regions of the country are also experiencing COVID-19 plateaus, according to Biobot’s data. The West Coast and Midwest have slightly higher coronavirus levels than the Northeast and South, but there aren’t huge differences between the regions.

    The West and Midwest are also hotspots for XBB.1.16 and XBB.1.9, the two Omicron subvariants that have started competing with XBB.1.5 over the last few weeks. This competition is happening slowly; XBB.1.5 declined from an estimated 84% of new cases during the last week of March to 69% of new cases this past week, according to the CDC’s estimates.

    At this point, it’s hard to tell how much of an impact the latest variants will have on overall COVID-19 spread. And these connections likely will only get more difficult to parse out, as PCR testing continues to decline and reporting gets less reliable. The CDC itself is currently evaluating how to adjust its data-sharing practices when the federal public health emergency ends on May 11.

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  • National numbers, April 23

    National numbers, April 23

    Coronavirus concentrations are trending down in Boston’s wastewater, a promising signal.

    In the past week (April 13 through 19), the U.S. officially reported about 94,000 new COVID-19 cases, according to the CDC. This amounts to:

    • An average of 13,000 new cases each day
    • 7% fewer new cases than last week (April 6-12)

    In the past week, the U.S. also reported about 12,000 new COVID-19 patients admitted to hospitals. This amounts to:

    • An average of 1,700 new admissions each day
    • 3.7 total admissions for every 100,000 Americans
    • 8% fewer new admissions than last week

    Additionally, the U.S. reported:

    • 1,200 new COVID-19 deaths (170 per day)
    • 74% of new cases are caused by Omicron XBB.1.5; 11% by XBB.1.9; 10% by XBB.1.16 (as of April 22)
    • An average of 35,000 vaccinations per day

    Across the U.S., COVID-19 spread continues at a moderately high plateau as newer versions of Omicron compete with XBB.1.5. Officially-reported cases and new hospitalizations declined by 7% and 8% respectively, compared to the prior week.

    Wastewater surveillance data from Biobot and from the CDC similarly show that COVID-19 spread is at a plateau. Nationally, coronavirus concentrations in sewage are higher than they were at this point in 2021 (when the initial vaccine rollout was in full swing), but lower than at this point in 2022 (when BA.2 had started spreading widely).

    Of course, it’s important to flag that official case counts are becoming even more unreliable these days, as PCR testing becomes increasingly difficult to access and state health departments no longer prioritize timely reporting to the CDC. According to CDC, five states didn’t report COVID-19 cases and deaths last week: Arkansas, Florida, Iowa, Mississippi, and Pennsylvania. (Iowa has permanently stopped reporting.)

    These case reporting issues are likely to continue—and perhaps accelerate—when the federal public health emergency ends next month. I’m thinking about how to adjust these National Numbers reports when that happens; that will likely involve foregrounding wastewater data and hospitalizations rather than cases.

    Regionally, Biobot’s surveillance shows a slight uptick in coronavirus spread on the West Coast and declines in the other major regions. Some counties in California have reported recent increases in wastewater, according to Biobot and WastewaterSCAN, but it’s currently tough to tell if this is a sustained surge or isolated outbreaks.

    The West Coast and Midwest continue to be hotspots for newer versions of Omicron, according to the CDC’s estimates, with XBB.1.9 still most prevalent by far in the region including Iowa, Kansas, Missouri, and Nebraska. Nationwide, the CDC estimates that XBB.1.9 caused about 11% of new cases in the last week and that XBB.1.16 caused 10% of new cases.

    XBB.1.16 (also called “Arcturus”) was recently classified as a variant of interest by the World Health Organization because it can spread significantly faster than other Omicron lineages. The variant is likely to “spread globally and contribute to an increase in case incidence,” according to the WHO.

    While I’m wary of the new variants, I have been heartened to see coronavirus levels in wastewater remain mostly at plateaus—or even decline—in many places across the U.S. In Boston, for example, coronavirus levels have been on a downward trend since early 2023. I hope to see this trend continue. 

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  • National numbers, April 16

    National numbers, April 16

    New subvariants XBB.1.16, XBB.1.9.1, and XBB.1.9.2 are on the rise, according to the CDC’s estimates.

    In the past week (April 6 through 12), the U.S. officially reported about 100,000 new COVID-19 cases, according to the CDC. This amounts to:

    • An average of 15,000 new cases each day
    • 17% fewer new cases than last week (March 30-April 5)

    In the past week, the U.S. also reported about 13,000 new COVID-19 patients admitted to hospitals. This amounts to:

    • An average of 1,900 new admissions each day
    • 3.9 total admissions for every 100,000 Americans
    • 14% fewer new admissions than last week

    Additionally, the U.S. reported:

    • 1,300 new COVID-19 deaths (190 per day)
    • 78% of new cases are caused by Omicron XBB.1.5; 9% by XBB.1.9; 7% by XBB.1.16 (as of April 15)
    • An average of 35,000 vaccinations per day (CDC link)

    COVID-19 spread appears to be at a continued plateau nationally, with slight declines in cases, hospitalizations, and viral concentrations in wastewater. New variants are on the horizon, though, at a time when data are becoming increasingly less reliable. 

    The CDC reported about 100,000 new cases this week, the lowest this number has been since early summer 2021. Unlike that period, however, PCR tests are much less available and reporting infrastructures are being dismantled.

    Wastewater surveillance data from Biobot show that transmission is actually several times higher now than it was at that previous low point. We’re in an undercounted plateau, rather than a real lull. Even so, less COVID-19 is spreading now than we’ve seen throughout the last few months.

    To get a more accurate picture of potential COVID-19 case counts in your area, I recommend going to the Iowa COVID-19 Tracker, an independent dashboard run by Sara Anne Willette. Willette has mapped out “likely cases per 100,000 people” by county, by multiplying the CDC’s data by 20 to account for underreporting.

    Wastewater data suggest that most parts of the U.S. are seeing steady (though slight) declines in transmission, with the exception of the West coast. Some counties in California have reported increased coronavirus levels in wastewater in the last week, according to Biobot and WastewaterSCAN, including parts of the Bay Area.

    One culprit for the increases could be newer Omicron subvariants, particularly XBB.1.9 and XBB.1.16. The CDC added XBB.1.16—which has drawn international concern, due to its connection with a recent surge in India—to its variant proportion estimates, along with XBB.1.9.2, a relative of XBB.1.9.1. (Yes, we’re getting into alphabet soup territory again here.)

    Nationally, the CDC estimates that XBB.1.16 caused about 7% of new cases in the last week, while the XBB.1.9s together caused 9%. At the regional level, XBB.1.16 is more prevalent in the West and Southwest (at over 20% of new cases in the region including Texas and other Gulf coast states), while the XBB.1.9s are more prevalent in the Midwest.

    The CDC published its second-to-last data update yesterday (which is still called the “Weekly Review,” even though it is far from weekly at this point). According to this update, most of the CDC’s public COVID-19 data “won’t be affected by the end of the public health emergency,” though the agency says it’ll provide more details in its final update on May 12.

    I personally expect that, while the national data systems might remain in place, more state and local health agencies will stop reporting, as we saw from Iowa recently. This will, of course, make the numbers less and less reliable.

    more national numbers