Expect variant to drive up serious cases
This month, with the delta variant loose and only half of eligible Texans fully vaccinated, COVID hospitalizations in Texas have more than doubled. Texas Medical Center CEO Bill McKeon says that our area’s COVID “fourth wave is beginning in force.”
What does all that mean? To explain, we turn to one of my favorite regular guests: vaccine researcher Peter Hotez, one of the country’s most visible scientists during the pandemic. At the Texas Children’s Hospital Center for Vaccine Development, he and his team have developed a low-cost COVID-19 vaccine for the developing world. He’s also dean of the National School of Tropical Medicine at Baylor College of Medicine.
This interview has been edited for length and clarity.
Can you start by giving us an overview of what’s going on with the delta variant?
We’ve kind of been through this before — or at least, we did the dress rehearsal when we had the B-1.1.7 variant from the U.K. We learned that variant was 50 percent more transmissible than the original lineage.
Now this delta variant has emerged out of out of India. It really swept across India very quickly, outcompeting everything because it’s so much more transmissible. Then it hit the U.K., and the same thing happened: It totally overran the British Isles.
Now it’s happening here as well. It started a few weeks ago, and according to the Centers for Disease Control and Prevention, it already accounts for 83 percent of the variant isolates in the U.S. So this is now sweeping across the country.
The problem is, it’s twice as transmissible as the original lineage. This is like nothing we’ve ever seen before. It’s not quite as transmissible as something like measles, but it’s getting up there in terms of its reproductive number.
So understanding why that is and understanding what that means for both unvaccinated and vaccinated people has become important.
I’ve been hearing that with delta, the viral load is more than 1,000 times higher than with that original-lineage virus, the one from 2020. What does that mean?
It’s a preliminary finding posted on a CDC discussion group. The study is from Guangdong province in southern China. It looks pretty credible, but it’s not yet been peer-reviewed.
They identified an index case of someone with delta, then identified the 167 contacts. Based on how quickly things became PCR-positive, they estimated that the amount of virus is about 1,000 times higher.
Potentially a reason why delta is more transmissible than anything we’ve seen is it’s more efficient at replicating, especially in the upper airways in the mouth. So when people are releasing virus, they’re releasing a lot more virus. If that turns out to be the case — you know, in proper peer-reviewed studies — that has that has a lot of important implications, both for unvaccinated and vaccinated individuals.
When you’ve got this as the dominant variant, if you’re unvaccinated and you’ve been lucky enough not to get COVID so far, you have to recognize there’s a good chance your luck’s about to run out, and you will likely get get COVID. You should get vaccinated yesterday, right? This is not the time to wait, because the spread of delta is accelerating very quickly.
It also has some implications for vaccinated people, I think, although we don’t have the data to document it. I’m being asked a lot: If we’re vaccinated, should we still don masks and take all those other precautions?
Unfortunately, it’s not a quick answer. I haven’t found a way to say it succinctly yet. I struggled to to talk about it on CNN last night: They want things said quickly, and with this you can’t — it’s a fairly nuanced explanation.
It goes like this: In the past, with the original lineages, the studies out of Israel and elsewhere showed that not only did being vaccinated inhibit symptomatic illness, but it also largely halted asymptomatic transmission. That meant that if you had your virus-neutralizing antibodies, those virus-neutralizing antibodies would also go into the mucous membranes of your nose and mouth and stop virus shedding. That’s the likely mechanism by which the vaccines stopped asymptomatic transmission.
On that basis the CDC felt comfortable concluding — and I agreed with their decision — that if you’re vaccinated, even if you get the virus infection, you’re shedding so little virus that you’re not going to transmit it to anybody. Therefore, if you’re vaccinated, you don’t need to be tested any further.
I felt then that extended to things like Major League Baseball: If you’re vaccinated, stop testing because even if you’re PCR positive, you’re not transmitting the virus. And it meant you could probably feel comfortable walking around vaccinated even in indoor settings without a mask. Even if you acquired the virus, there’s not enough virus there to have an impact on you, or to have an impact on anybody you might bring the virus home to — because you’re not shedding enough virus.
That was good. On that basis, a lot of us felt that if enough of us get vaccinated, we can return to prepandemic life. I still think that’s the case. But now there’s an asterisk on it.
The asterisk on it is this delta variant. Because this is such a higher viral load, if you’re infected, you still may still be shedding enough virus to infect others. That’s the worry. But we have no evidence for that either. There are no studies yet.
So the question is, what’s the interim guidance until we have evidence one way or another? Should we revisit masking indoors?
One of the most commonly asked questions I get is this: I’m a parent,
I’m vaccinated but I have little kids who are not old enough to be vaccinated. Is there a risk that I could shed virus and pass COVID to my kids? In the past, my answer was, “No, that’s unlikely.” Now the answer is “I’m not so sure.” This is getting a lot of people worried and upset.
We don’t hear that kind of nuance from our public health experts, at least in Washington and Atlanta.
So if the delta variant means that a vaccinated person can shed virus, what else in addition to masking, can we do?
Maybe a third immunization is not such a bad idea. Because that third immunization for the mRNA vaccines, or a second for Johnson & Johnson, will really jack up your virus-neutralizing antibodies. And in the arms race between antibody and virus, enough antibodies will be put into your mucous membranes that they will potentially cause shedding to stop.
Those are the kinds of discussions I’m having with leadership in Washington and elsewhere.
A lot of this would be moot had we done a better job vaccinating the country, right? We might have prevented delta from getting a firm foothold in the first place. We screwed up that opportunity.
Even now, if we could vaccinate everybody, we might be able to vaccinate our way out of it — but not at the rate we’re going. I mean, we’re doing pretty well in Massachusetts and Vermont and the New England states, and in the northeast parts of the West Coast.
But here in the South, you know, so few people are getting vaccinated, delta is just ripping through.
The CDC doesn’t currently recommend a third shot for the mRNA vaccines, or a second shot for Johnson & Johnson.
What would it take for them to change that recommendation?
That’s a good question. The Pfizer CEO sent out a press release saying they’re gonna file for emergency use authorization (for a third dose). I thought that was an odd way to do it, but maybe given the time frame required, that’s what’s needed. The problem with that press release was, there was no supporting data to justify that. Had we all seen (a recent study) maybe it would have made more sense at the time. So we have to see what kind of data the Pfizer people put in place for that emergency use authorization.
I also think we need to give some thought in terms of how quickly we move on it. I’m especially concerned about individuals on immunosuppressive therapy, because they don’t always seem to mount an adequate antibody response even with two doses.
So I would say a third dose should really be considered, especially for those who’ve had organ transplants and are on immunosuppressive therapy — or getting Car T therapy, or bone marrow transplants, or cancer chemotherapy.
Those are the people that would probably want to vaccinate pretty soon. The same goes for those of extreme age, women and those who have disabilities.
I think, hopefully, that we’ll get some guidance around that shortly. And also for the Johnson & Johnson vaccine. We have some new data that was put up on bioRxiv by a group at New York University showing that after a single dose, virus-neutralizing antibodies go down very quickly against the delta variant. That doesn’t mean it doesn’t work, but there’s enough there that I think we’re gonna have to look at a second dose of
J&J or boosting with one of the mRNA vaccines.
When the J&J phase one/phase two data came out last year, from the beginning, I thought this should be a two-dose vaccine. Maybe now it will actually be that.
With the delta variant loose, how should Houstonians be leading their lives? You and your family have been vaccinated. What precautions are you taking?
Other than the fact that I’m not traveling as much, my life now doesn’t look too different from prepandemic life. The big difference is lab meetings: We don’t have lab meetings in person. They’re virtual, and I’m looking forward to getting back to having them in-person again.
I come into the office every day. Sometimes I don’t exactly know why I come into the office: Oftentimes I come in, don’t see anybody, close the
door, and go on Zoom calls all day. But at least I feel like I’m in the mix. It gets me out fully dressed instead of half dressed, and that makes me feel better. It just normalizes things.
I don’t go into a lot of stores — I never went into a lot of stores — and if I do now, I wear a mask.
The open question is the restaurants. My son is my youngest son and his girlfriend are big foodies, and going to the restaurants in Houston is so much fun.
I know you love sushi.
Ann and I have been having sushi every other weekend, or something like that. That’s been really fun. But I don’t know what happens now.
With delta, do we go back to take out? That might be the one change we’ll have to make again. We’ll have to see how this goes.
We didn’t have to get here. If we had vaccinated everybody, we’d be in a much better position. It’s not for want of trying. I think both the mayor and the county judge, the city health department and Harris County Health Department — they all did as good a job as anybody in terms of ensuring access and putting messages out there.
But even with all of that, our vaccination rate is not nearly as strong as it is in the Northeast. That’s unfortunate. And now we’re going to see the consequences of that.
We’ll see the uptick in hospitalizations in our Texas Medical Center. I did an advisory about this yesterday with Dr. (Paul) Klotman, the president of Baylor, and Bill McKeon, the head of the Texas Medical Center.
We know the number of hospitalizations will continue to go up. The only silver lining might be that because relative to the rest of the world, Houston and the U.S. have done a little better vaccinating our oldest citizens, so we won’t see as many deaths. But we’re still gonna see a lot of hospitalizations and a lot of ICU admissions.
I hope there aren’t a lot of pediatric ICU admissions, but that’s what I’m holding my breath about. That’s what we are starting to see here and in certain parts of the country.
Is there anything else we should be thinking about now?
We have to recognize that it’s never too late. We can always keep vaccinating. The key is to be fully vaccinated.
We’ll have to see if what being fully vaccinated means in a few weeks. If it means even getting a third immunization, we’ll see how that pans out.
And of course, we have the problem of globally, things are as disastrous as they ever were. Africa is not vaccinated. No one’s vaccinating on the African continent, and South America is not doing much better. Southeast Asia is not doing much better, or at least parts of it: Indonesia now is suffering horribly.
Our lab has licensed our vaccine, not only to Biological-E in India, but also BioPharma in Indonesia. We’re hoping that has an impact. A colleague, Dr. Patrick SoonShiong, wants to build capacity in South Africa. So we’re hoping our vaccine can come in and be used to vaccinate the world.
The thing I’m worried about is the fact that the Biden administration has not taken ownership in producing vaccines for the world. We’re working with Congressman Michael McCaul about this. He’s been terrific: A lot of people don’t know that he has had a long-standing commitment to global health. I’m excited that Texas Children’s and Baylor are working with him, so I’m hoping he can help. He’s really working hard not to try to help us.
Thanks for talking with me. Even when you scare me, I feel I’ve learned something.
The key is not to be scared. The key is to be smart and recognize that this virus does create new challenges for us. We just have to respond, be evidence-driven and make good decisions.