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Catherine Troisi

A bit of good news in the wastewater

I’ll take it where I can get it.

Community spread of coronavirus is on the decline from its recent summertime high, but experts warn that Labor Day gatherings and kids’ return to classrooms could bring a rash of new infections in the coming weeks.

The latest samples of Houston’s wastewater — a highly sensitive method for tracking coronavirus — show diminishing traces of the virus across the region, said Loren Hopkins, the Houston Health Department’s chief environmental science officer. The results indicate a slight drop in person-to-person spread.

“The positivity rates are still alarmingly high, the wastewater rates are still alarmingly high, but it may be trending down,” Hopkins said Wednesday.

The decline could be short-lived.

The holiday weekend and the start of school, which spurred record infections among children, will likely keep the Houston area in “plateau mode” for the foreseeable future, said Bill McKeon, CEO of the Texas Medical Center.

On Tuesday, the Texas Medical Center reported that the rate of transmission across the Houston area was 0.87; the average for the previous week was 0.99. Both figures landing below 1.0 is a good sign; any number above 1.0 means the virus is spreading through the community.

Still, McKeon urged caution. Tuesday’s low daily transmission rate of 0.87 could be artificially deflated due to low testing rates, he said, which commonly occur over holiday weekends.

“We are just coming out of the Labor Day weekend and we typically do not see the impact of holidays for one to two weeks,” McKeon said.

[…]

Houston’s coronavirus hospitalizations slowed by 2.3 percent in the past week, but remained only slightly lower than August’s record peak. As of Tuesday, 3,370 people were in area hospitals for COVID-19, down from the record high of 3,500 on Aug. 24, according to the Texas Department of State Health Services.

Ballooning school transmissions are another concern, experts said, especially in districts that do not have mask mandates. Student infections are rapidly rising across the state, with the total number of positive cases among public school students surging by 90 percent just a few weeks into the new school year.

“We need mask mandates to protect our school children from getting infected and bringing it home to Mom and Dad,” said Catherine Troisi, an epidemiologist at Texas Medical Center’s School of Public Health.

The wastewater had documented to surge, and it will be the leading indicator when there is a real decline. I hope people were cautious over the Labor Day weekend, but we’ll know soon enough what if any effect that had. As for mask mandates in the schools, it seems to be working pretty well for HISD. I keep saying, none of this is a mystery, we know what we need to do, we just have to do it.

Back to Code Red

Pretty much inevitable at this point.

Harris County Judge Lina Hidalgo on Thursday returned the county to the highest COVID-19 threat level and urged unvaccinated residents to stay home and avoid unnecessary contact with others.

At a news conference, Hidalgo and Mayor Sylvester Turner pleaded with residents to get vaccinated, wear masks in public settings, and avoid hospitals except for life-threatening conditions.

“We find ourselves retracing our steps toward the edge of a cliff,” Hidalgo said. “It’s very conceivable that we can once again be heading toward a public health catastrophe.”

[…]

The county’s data report Wednesday evening showed how far and fast the situation has deteriorated: an explosion of new cases and a positivity rate of 16 percent. Hospitalizations in the Houston area have increased for 20 straight days and show no signs of slowing; they are on pace to set a pandemic record in about a week.

At its heart, the stay-home request of unvaccinated residents is toothless. Hidalgo lacks the authority to enforce it, let alone issue less restrictive edicts, such as mandatory mask wearing. As one of the most popular local elected officials, however, she hopes to shake residents from a sense of complacency that the pandemic is over.

“I know there’s a lot of conflicting messages, there’s a lot of confusion, so I don’t want to talk about what I don’t have the ability to do,” Hidalgo said of the state pre-emptions. “The truth of the matter is, the best we can do right now, the most we have the authority to do right now, is what we’re doing. So, we’re going to continue to make the most of that and really be direct about what we want the community to do.”

The mayor, who bucked the governor in requiring city workers to wear masks this week, said the numbers would dictate the city’s response to the virus. As of Thursday, 197 city employees had active cases of COVID-19.

“The numbers will dictate my response, and then we’ll deal with whatever happens after that. But I’m not going to be constrained by some order,” Turner said. “Wherever this virus goes, and whatever we need to do to check it and to save lives, is what I’m prepared to do.”

As the story notes, several other big counties have taken this step already, and more will surely follow. For those of you who like visuals, here you go:

Not a pretty picture at all. There’s nothing more Judge Hidalgo can do, since Greg Abbott has cut off any power that local officials had once had. I note that as of this writing, Mayor Turner’s employee mask mandate has not yet drawn a response from Abbott or Paxton. Makes me wonder if there’s more room to push the envelope a little, or if further provocation will draw their wrath.

While we can count on Judge Hidalgo to do everything she can to mitigate the spread of the virus, we can also count on her colleague to the north to do nothing.

COVID-19 cases and hospitalizations are continuing to increase dramatically in Montgomery County and around the region as the delta variant surges in unvaccinated residents.

While the Department of State Health Services recently started tracking cases in vaccinated people and specific data is not yet available, county health officials are reporting most new cases in unvaccinated residents.

“We can say that the vast majority of new cases, hospitalizations and deaths have not been vaccinated,” said Misti Willingham with the Montgomery County Hospital District. “Vaccines help reduce the risk of severe illness, hospitalization and death. Being vaccinated does a great job prepping your immune system should you encounter the virus.”

[…]

According to data from the health district since July 7, total hospitalizations in Montgomery County increased from 42 to 238 with 48 of those patients in critical care beds. MCPHD noted 157 of those 238 are Montgomery County residents.

The county’s active cases jumped 767 to 4,219. Since July 7, active cases in the county have surged by 3,624. The county’s total number of cases is now 60,941, increasing from 55,838 since July 7. Additionally, the county added three more reinfections bringing that number to 26.

However, health officials did not report any additional deaths from the virus. The total number of deaths remained at 354.

The county’s testing positive rate has climbed from 4 percent in early July to 19 percent. To date, 30,742 people have fully recovered.

Note there’s no comment from Montgomery County Judge Mark Keough in that story. Which is just as well, because when he does talk, this is the sort of thing he says. I have no words.

Since it’s all up to us to keep ourselves safe, we may as well remind ourselves of what we can do. Or at least, what we could do with just a little cooperation from our state government.

With COVID-19 cases and hospitalizations growing exponentially in Houston and Texas, responsibility for blunting the surge is still largely a matter of personal choices, leaving medical and public-health professionals pleading with Texans to be vaccinated, mask up and maintain social distancing.

On Wednesday, Texas reported 8,130 hospitalizations, a 44 percent increase since last Wednesday. At Texas Medical Center hospitals, 311 patients were hospitalized for COVID, up from 61 only a month before.

“When all the indicators head in the same direction, that gives you a good idea,” said epidemiologist Catherine Troisi, who teaches at UT School of Public Health. “Right now everything is looking bad.”

[…]

“Delta is so transmissible, it’s picking off anyone who’s unvaccinated,” said Peter Hotez, co-director of the Texas Children’s Hospital Center for Vaccine Development and dean of the National School of Tropical Medicine at Baylor. “That’s what’s been happening in Louisiana and Mississippi, and now it’s starting here.”

Of the three main strategies to blunt the effect of the coming surge — vaccinating, masking and social distancing — Hotez favors vaccinations, and says it’s crucial to administer as many as possible immediately.

“If we wait until mid-surge, a vaccine campaign will be much less effective,” he said. “If ever there were a time to vaccinate, it’s now.”

He continued: “The single best thing we could do is mandate vaccinations for schools, but in Texas we’re not even talking about that. We can’t even mandate masks.”

Troisi agreed that urging individuals to act responsibly isn’t enough.

“From a public health standpoint,” she said, “we need to get people vaccinated, and we need to increase testing. Maybe we don’t have to mandate vaccines. But you shouldn’t be able to go into Target or eat at McDonald’s if you’re not vaccinated. There have to be consequences for not getting the vaccine. You can’t just put other people at risk.”

The delta variant moves faster than previous coronavirus strains, notes Spencer Fox, associate director of the UT COVID-19 Modeling Consortium.

“With the traditional coronavirus, if someone is infected, on average they’re infectious starting two-and-a-half days after infection and show symptoms at five days,” he said. “But with delta, a key difference is that the time between exposure and being infectious is shorter by a day.”

A percentage of people infected today are almost certain to need hospitalization within one to two weeks. So preventive measures taken today, he said, “will help reduce hospitalizations a week from now, and will have major impacts two weeks from now.”

In other words, all of the same risk-minimization techniques we had before, back when we didn’t have an amazingly effective vaccine that was free and available to everyone over the age of 12 to really truly minimize the risk. I’m going to boil it all down to “get you and everyone in your family who is eligible vaccinated, and do everything you can to avoid any contact with unvaccinated people”.

For sure, stay the hell away from this.

Texans for Vaccine Choice will host a rally on the steps of the Texas Capitol later this month, protesting “the current state of medical mandates” as the state grapples with a surge in COVID-19 cases and stagnating vaccination rates.

The rally is scheduled for Aug. 21 at 11:30 a.m. A panel discussion will address the state’s current COVID protocols and vaccine requirements.

“I’m speechless,” Dr. Peter Hotez said Thursday morning. “To do that when there’s a public health crisis, with COVID rates going up — it’s terrible.”

As someone once said, terrible is as terrible does. If the COVID they will spread could be limited to just them it would be one thing. But it’s not, and so here we are.

We’re (sort of) halfway vaccinated

It depends on how you’re measuring it. And it’s still not enough, no matter how you look at it.

Texas has hit the halfway point.

As of Friday morning, 50.1 percent of Texans 18 and older are fully vaccinated from COVID-19, according to the Centers for Disease Control and Prevention.

While this is a milestone for the state, Dr. Susan McLellan is not celebrating.

“It means that 50 percent are not vaccinated, and that’s a problem,” said McLellan, professor of infectious diseases at University of Texas Medical Branch. “It’s been available for everybody 12-and-older for months. I don’t think that’s a very wonderful milestone.”

McLellan and other Texas doctors are concerned about the coronavirus case rate and the country’s newly-introduced, highly-transmissible delta variant. Now the dominant COVID strain in the U.K., experts expect the delta variant to become the dominant strain in Texas, as well.

Early studies show vaccination provides better immunity than contracting the virus does, McLellan said.

“Right now, there are pockets in the population that are not getting vaccinated, and they tend to congregate,” she said. “Young adults may think it’s no biggie to not get vaccinated, and then they go to a bar with a lot of people like them. They easily expose each other and spread it around.”

State vaccination rates can be misleading as a large percentage of vaccinated people live in large urban centers, such as Houston, Austin and Dallas, said Dr. David Lakey, a member of the Texas COVID-19 Expert Vaccine Allocation Panel.

In Harris County, more than 1.8 million people are now fully vaccinated, followed by Dallas County at 1 million. In Travis County, more than 631,000 people are fully vaccinated, the DSHS reported Friday.

[…]

Texas ranks 33rd among all states for its rate of vaccination. And its proximity to states with low vaccination rates — including Louisiana, Mississippi and Alabama — could pose a threat to Texans, said Dr. Catherine Troisi, an epidemiologist with UTHealth School of Public Health.

“We don’t live in a bubble,” Troisi said. “People travel from state to state, and they can bring the infection with them.”

This story measured the vaccination rate for people 18 and older. Of course, kids are still vulnerable to COVID, and you can get vaccinated if you’re at least 12 years old, so that’s a somewhat odd way of measuring progress. The Trib identifies 40% of the state’s total population as being vaccinated, with Harris County continuing to be right at the same level as the state as a whole. They give totals for “people who are fully vaccinated”, which will include people who have had two Pfizer or Moderna shots plus people who got the one-shot J&J vaccine, and “total number of shots administered”, which includes people who have had just their first Moderna or Pfizer shot. I estimate from this that Harris is close to fifty percent of the total population having at least one shot, again consistent with the statewide number.

So that’s good and the number will continue to rise, but much more slowly since basically everyone who was eager to get a shot has had theirs. We’re fully into the “people who are hesitant” and “people who face obstacles” part of the journey, and that’s just going to take longer. In the meantime, the Delta and other variants are surging in the parts of the country (and elsewhere) that are less vaccinated, and while hospitalizations remain at manageable levels, that could change. A lot of the country, and a lot of Texas, remains at high risk because of low vaccination rates. I don’t know what more we can do about that.

Please get your second shot

I hope this is mostly a function of incomplete data.

Millions of Americans — including tens of thousands of Houstonians — either have delayed or are forgoing their second dose of a COVID-19 vaccination.

As of late last month, roughly 51,000 people who received their first inoculation through the Houston Health Department were “overdue” for their second dose. The department’s number is preliminary but includes any person who has gone at least 42 days since their first round without returning for a second shot.

Statewide, more than 630,000 of the roughly 11 million people who’ve received one dose are more than six weeks overdue, the Texas Department of State Health Services told the Houston Chronicle.

“We need a lot of those folks from February to come back in and get their second dose now,” Dr. David Lakey, a DSHS commissioner who sits on Texas’ COVID-19 Expert Vaccine Allocation Panel, said last week.

Part of the gap, however, is likely due to people who opted to receive their second dose through other health care providers as vaccine availability expanded.

It’s not cause for alarm just yet, said Rice University health economist Vivian Ho, though she said the trend does not bode well for the overall goal of herd immunity.

[…]

Ho said people shouldn’t be dissuaded from rescheduling appointments that they missed, as they’ve been shown to give additional antibodies even if they come late.

“The first dose really does boost your antibodies, but it’s the second that really gives you the second umph,” she said.

Houston Methodist radiologist Dirk Stotsman worried that some people are forgoing their second round of inoculations because the first doses of Moderna and Pfizer have been proven highly efficacious against the virus.

While the first dose offers a good level of protection, he said, the extra antibodies provided by the second dose will be integral to prevent the spread of more infectious and dangerous strains of the virus.

Getting just the one Pfizer or Moderna shot is better than nothing, but it’s not as good as it should be. If you’ve gotten one shot and for whatever the reason not gotten the second one, it’s not too late. Go ahead and make an appointment or do a walk-in where available.

In related news:

With the rescission of the mask mandate and full reopening of businesses, medical experts worried spring would bring a debilitating fourth wave of COVID-19 infections to Texas.

But as vaccination rates slowly leveled off in recent weeks, the rate of infections and hospitalizations did as well. More than a year after businesses closed, offices sent workers home and traffic vanished from Houston’s concrete jungle of freeways, public health officials are cautiously optimistic efforts to quell the spread of the virus and vaccinate as many people as possible are working.

Yet despite claims from officials like Gov. Greg Abbott that this downturn is linked to “herd immunity” — the mysterious target ranging between 60 and 80 percent fully vaccinated against COVID-19 — experts say Texas cannot rely on vaccinations alone to achieve what some think may mean the end of the pandemic.

“Nobody knows for sure what’s going to happen,” said Catherine Troisi, an infectious disease epidemiologist with UTHealth School of Public Health in Houston. “But my educated guess would be as more of the population becomes either vaccinated or immune through natural infection, we won’t see as many cases.”

Fewer than 3,000 patients have been hospitalized across the state for the past five weeks, according to a Chronicle data analysis. It’s the longest streak with that few patients since June 2020.

Dr. Carl Vartian, chief medical officer at HCA Houston Healthcare’s Clear Lake and Mainland hospitals, worries the public conflates “herd immunity” with “ending COVID-19.” But COVID-19 may not truly end. Rather, experts suspect it will become “endemic,” never fully leaving the population — like influenza, which still infects hundreds of thousands of people a year in the U.S.

Again, what we have now is better than what we had before, but not as good as it could be. Even at “herd immunity levels”, there’s still a lot of unvaxxed people. The difference is that it becomes harder for the virus to really take off as it has done before. But people can and will still get sick and die if they’re not vaccinated. It’s up to us what the level of those illnesses and deaths are.

We are not ready to re-reopen

I don’t know who needs to hear this, but…

Texas COVID-19 hospitalizations have declined the most significantly — 4,144 Tuesday, down from 10,893 on July 22 — but new cases, positive test rates, daily deaths and viral spread are all dropping. They are dropping enough that one Texas modeler, Spencer Fox of University of Texas at Austin, went so far as to say he thinks that Texas may have seen the worst of the pandemic — as long as people continue to wear masks and keep their guard up.

A number of other health experts warned against lifting restrictions, noting that the coming Labor Day weekend, the expected resumption of schools and seasonal weather changes have the potential to cause a resurgence like Texas experienced earlier in the summer. They also said the amount of transmission, although improved, is still way too high.

“I don’t want to be Debbie Downer, but we’ve been surprised before,” Catherine Troisi, an infectious disease epidemiologist at the UTHealth School of Public Health, said last Friday. “It’s a double-edged sword when things start looking better. The virus is still out there, but people think things can go back to normal.”

Troisi added that some experts are hesitant because of the state’s data reporting problems, because it’s possible some other issue will surface. Those problems include under testing, coding errors that caused backlogged results and combining positive diagnostic and antibody tests.

Chris Amos, a Baylor College of Medicine quantitative scientist, said “the timing could not be worse for rolling back.”

“Given the number who test positive reflect perhaps 10 times as many individuals who have not been tested but are positive,” said Amos, “there remains a large pool of individuals who can spread COVID-19 if they begin interacting with many others, and particularly if we allow large groups to start coming together again.”

Amos acknowledged that optimism about opening up is natural given the slowing of COVID-19’s spread. The spread is measured by a value, known as reproductivity, that suggests a slowing or growing of the virus. Over 1 means each infected person transmits it to an average of more than one person and the epidemic grows; under 1 means the virus is transmitted to less than one person and the epidemic won’t sustain itself.

The value for the state overall has been under 1 since July 20.

According to Amos’ calculations, if the state maintains the current trend, with the number around 0.87, it would take 38 days to reduce the COVID-19 burden by another 50 percent.

It’s important to keep reducing that burden before students resume in-person classes, Amos said. He and others advised against a one-size-fits-all approach.

“Not every community or county in Texas is experiencing the same burden of disease,” said Angela Clendenin, an epidemiologist with the Texas A&M School of Public Health. “In some places, it may be justified to roll back some restrictions whereas in others, it’d be ill-advised to do so. It will be critically important that rolling back restrictions does not send the message that we are somehow ‘all clear.’”

See here for the background. The basic fact remains that we are still at levels well above where we were in early June, when we first re-opened. There’s no question that if we re-reopened like we re-opened the first time around, we will get the same result. To me, three things are clear. One we shouldn’t change anything until we are back at early-June levels. Two, we should have sensible objective metrics that we can actually measure with accuracy and that we stick to, unlike the first time around. And three, give some discretion back to local jurisdictions so that the counties with a sufficiently low infection rate can be more open (though still within state guidelines) while those that aren’t ready for that kind of openness can continue to do what they need to do to get there. All of this should be screamingly obvious after what we just went through, but I see no reason to believe that Greg Abbott or Dan Patrick have learned anything from that experience.

Who needs testing?

It’s the surest way to see the infection rate decline, am I right?

The number of Texans being tested for the coronavirus has fallen sharply in recent weeks, a trend that has worried public health experts as officials consider sending children back to school while thousands more Texans are infected each day.

In the week ending Aug. 8, an average 36,255 coronavirus tests were administered in Texas each day — a drop of about 42% from two weeks earlier, when the average number of daily tests was 62,516.

At the same time, the percentage of tests yielding positive results has climbed, up to 20% on average in the week ending Aug. 8. Two weeks earlier, the average positivity rate was around 14%.

On Saturday, the state set a record for its positivity rate, with more than half of that day’s roughly 14,000 viral tests indicating an infection.

Taken together, the low number of tests and the large percentage of positive results suggest inadequacies in the state’s public health surveillance effort at a time when school reopenings are certain to increase viral spread, health experts said.

“Opening the schools is a really complicated problem, and the best thing we can do is get the number of cases down so kids can go back to school safely,” said Catherine Troisi, an infectious disease epidemiologist at UTHealth School of Public Health in Houston. “There are so many reasons why kids need to be in school, particularly younger kids, but we’re finding out more and more they can get infected, and the concern is them bringing it home and spreading in the community and spreading to teachers.

“I think the worst thing would be for schools to open, then close,” she said. “That really makes it hard on parents, that unpredictability, and there’s a lot of costs associated with opening the schools safely.”

[…]

The number of tests performed in Texas has “never been great,” said Vivian Ho, a health economist at Rice University and Baylor College of Medicine, but “it’s extremely troubling” that the numbers have dipped since last month.

“It’s troubling because we can guess at some of the reasons, but we’re not sure,” she said.

She suggested that some people may have been discouraged by long wait times for test results, or less concerned about the virus’ toll in Texas after a frightening peak in July began to flatten out.

A declining number of tests is a particularly thorny issue for schools, Ho said. “No public school has the resources to do testing under the current circumstances. There are huge class sizes and crowded hallways,” she said.

Does any of that sound good to you? Because none of it sounds good to me. Again I say, remember when Greg Abbott’s plans for reopening included sufficient testing capacity and a positivity rate under ten percent? Boy, those were the days. Oh, and as the story notes, the TEA still hasn’t yet released any specifics on which districts will be able to receive waivers to limit in-person instruction beyond eight weeks or under what circumstances. So, you know, the school situation remains a mess. Isn’t this fun?