Zika Vax in the Works; STI Guidelines Updated

TTHealthWatch is a weekly podcast from Texas Tech. In it, Elizabeth Tracey, director of electronic media for Johns Hopkins Medicine, and Rick Lange, MD, president of the Texas Tech University Health Sciences Center in El Paso, look at the top medical stories of the week.

This week’s topics include screening for chlamydia and gonorrhea, whether COVID boosters are needed, hospitalizations and deaths due to COVID among vaccinated and unvaccinated persons, and a vaccine for Zika.

Program notes:

0:36 Vaccination status and COVID

1:37 Vaccine very effective at preventing hospitalization and death

2:32 Boosters are not needed

3:31 Primary goal should be to get most fully vaccinated

4:36 Short follow up

5:35 A Zika vaccine

6:35 With electroporation

7:35 Novel development

8:21 USPSTF on screening for chlamydia and gonorrhea

9:21 Asymptomatic infections in men generally

10:20 STIs have increased to a 20 year high

11:46 End

Transcript:

Elizabeth Tracey: An update to the guidelines on screening for gonorrhea and chlamydia.

Rick Lange, MD: An anti-Zika vaccine in the works.

Elizabeth: Should we give boosters for COVID?

Rick: And monitoring hospitalizations and cases and deaths of COVID related to vaccine status.

Elizabeth: That’s what we’re talking about this week on TT HealthWatch, your weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso. I’m Elizabeth Tracey, a Baltimore-based medical journalist.

Rick: And I’m Rick Lange, president of Texas Tech University Health Sciences Center in El Paso, where I’m also dean of the Paul L. Foster School of Medicine.

Elizabeth: Why don’t we turn first to one of the ones that’s gotten a tremendous amount of press this week — that’s the data from the CDC in Morbidity and Mortality Weekly Report. What about all of this hospitalization, death, and so forth, that you’ve already served up so eloquently?

Rick: This talks about two things: COVID cases, hospitalizations and deaths by vaccination status, but also it does it during a time period where we saw an increase in the Delta virus. They looked at data from April 4th to July 17th of this year. They looked at 13 U.S. jurisdictions. They calculated what they would call the “incidence rate ratios” — the number of individuals who got infected, hospitalized, or died that were unvaccinated versus those who were vaccinated.

Overall, the vaccination status obviously makes an important difference. There is no question about it. About 92% of the individuals that were hospitalized or had COVID or died were unvaccinated. However, when they looked at each of these individual characteristics over the course of time as the Delta variant emerged, it looked like the vaccine was a little bit less effective at preventing COVID, but still very effective at preventing hospitalization or death.

Let’s put some numbers on it. The vaccine effectiveness decreased from 91% to 78% in terms of preventing infection, but there was really no significant decrease in preventing hospitalizations or deaths during this particular time. By the way, most of the hospitalizations and deaths occurred in individuals over the age of 65.

Elizabeth: This is such an important take-home. If you are not vaccinated, it’s really time to go out and get vaccinated, folks. There is no question about it. I have seen some other emerging data that suggests that the Moderna vaccine is more efficacious than the Pfizer vaccine.

Rick: This particular study doesn’t address that; they just lumped all vaccinated people together. They had to be fully vaccinated — that is, receive both doses — but they really didn’t distinguish between the various vaccines in this particular study.

Elizabeth: Why don’t we turn to The Lancet? This is a viewpoint where a very large number of folks got together and assessed the literature relative to whether or not we need a booster if we are fully vaccinated against COVID-19. They took a look at all of the — both, randomized controlled trials, where there is a paucity, as well as observational trials. Actually, two officials from the FDA are part of the signatories of this particular viewpoint.

They basically conclude that there is no reason for us to be giving boosters to people who are fully vaccinated right now for exactly the reasons that you just cited, that there is this persistent reduction in severe disease, hospitalization, and death if you are fully vaccinated. They say we should be a good deal more vested in providing the vaccine to folks worldwide who are unvaccinated at this point than we should be in providing boosters to people who are already fully vaccinated.

Rick: There is no doubt about it. The primary goal should be to get as many people fully vaccinated as we can. However, as we discussed, Elizabeth, there is clear evidence that the vaccine effectiveness wears off in terms of preventing infection. I am not so sure that this viewpoint is shared by everybody in terms of making sure they try to hit the high-risk groups: immunocompromised, those that are older, those who have comorbid conditions. There is still a group that are vaccinated, they still end up hospitalized, they still end up dying, and they may benefit from a booster shot.

Elizabeth: Well, one of the things they point out in this opinion piece is that, that Israel data, which a lot of people have been holding up as an impetus for widespread booster vaccination, is somewhat questionable. They say that the effectiveness against severe disease in Israel was lower among people vaccinated in either January or April compared to those vaccinated in February or March. That’s so inexplicable. How can we explain, “Well, all right, if you got it in January or April, you’re at higher risk than if you got it in February or March”? They also point out that their mean follow-up was only about 7-person days, so really short.

It’s unclear to me, Rick, and I have to be honest. I mean, I would like to obtain a booster vaccine, even though I’m fully vaccinated, I don’t have any comorbidities, and I’m not in a high-risk group for any reason other than potential exposure from being in the hospital. How do we address this among the worried well?

Rick: I think one of the things that this viewpoint brings out is, we just need more data. At this particular time, I say the data we have are really incomplete. We have a Delta variant that is twice as infectious. We do know that many of the shots that we give [that are] more than one dose aren’t spaced 3 to 4 weeks apart — they’re spaced months apart and sometimes even a year apart.

I think this particular time people choose based upon the available information, while we are continuing to get information. This is very fluid at this particular time. I do understand their point is that we want to get more people around the world vaccinated and I think that should be a primary goal as well.

Elizabeth: Let’s turn, since we’re talking about vaccines, to the New England Journal of Medicine, a vaccine against what looked a while ago to be something really scary and now pales in comparison to COVID: the Zika virus.

Rick: I agree. I mean, it looked really scary — and this is pre-COVID — and now it’s kind of faded away. It’s an endemic in Asia and Africa and it really reared its head in about 2015 in Brazil. It actually made its way here to the United States as well.

It’s usually a self-limiting disease. People have a fever and a rash, maybe some joint and muscle pain, but it usually goes away. Where it was particularly problematic is infection during pregnancy has been associated with severe congenital birth defects. There is a rare individual that has developed Guillain- Barré neurologic symptoms. We’d like to have a vaccine so that if it does become epidemic again, we have some way of controlling it.

This is a look at the safety and immunogenicity of a DNA vaccine — DNA contained in a plasmid. It’s injected just beneath the skin. They do something called electroporation, which is neat. They apply a little bit of electrical stimulus there, over the course of less than a minute, to actually drive that DNA into the cells. When that DNA gets into the cells, it prompts the production of proteins that are usually contained in the Zika virus, and also what’s called an envelope protein.

Forty participants total, 20 of whom received the vaccine and 20 of whom received placebo. What they are able to demonstrate is that they could elicit both binding antibodies and neutralizing antibodies in most of these individuals.

They took the serum from these individuals and injected it into mice, and they exposed the mice to toxic levels of Zika virus. What they found is that the antibodies was 91% effective in preventing death. The mice that received none of the serum all died, but those that received the serum from the individuals that had received the vaccine, 91% of the mice lived.

Elizabeth: One of the things I found really attractive about this study was just the novelty of this approach to the creation of a vaccine and also the novelty relative to its administration, the use of the electrical current. I wonder how practical that might be over the long haul.

Rick: That’s a great question. Electroporation takes a really small amount of time, but Elizabeth, it’s worth pointing out there are a number of different vaccines that are being developed right now to address Zika.

Elizabeth: Well, I would have to say that at least right now, to me, it looks like the COVID pandemic has really broken open a lot of this vaccine development. I think it’s really interesting and could be very beneficial.

Rick: But what I want our listeners to know is they say, “Well, gosh, these are being developed so fast.” Now, we have been working on these types of vaccines for over a decade now. We have accelerated our investigation and use of them, but we have been laying the groundwork foundation of this for over a decade, so it’s built upon strong foundation.

Elizabeth: Speaking of foundations, then let’s turn to the USPSTF and in JAMA this week; they have new recommendations relative to screening for chlamydia and gonorrhea. The last time the USPSTF took a look at this was in 2014.

Of course, they took a look at all of the studies that are relative to these particular issues, and they have given B recommendation — so moderate certainty — to screening for chlamydia and gonorrhea in all sexually active women 24 years of age or younger, and in women 25 years or older who are at increased risk for infection. That’s women who may be changing partners, don’t regularly use condoms, and other potential risk factors that may put them in that risk category. They say that right now the evidence is insufficient to assess the balance of benefits and harms of screening for chlamydia and gonorrhea in men. As we know, these are often asymptomatic infections in men and so I don’t know — I’m a little bit troubled on some level about that.

Rick: What they are trying to do is get all the data together and say, “Okay, this is what the data show. When the data are inconclusive, we can’t draw conclusions.” They are very honest about that. The recommendations are very good for women under age of 24 and those over the age of 25 with risk factors. I have to agree that we just don’t know enough about whether to do it in men, particularly in men that have sex with men, whether the risk is even higher. What that means is we just need to get new data.

With respect to the women over the age of 25 with increased risk, you mentioned some of them, if they have had a previous sexually transmitted infection, new partner, or more than one partner, if their partner is having sex with other partners at the same time, or their partner has had a sexually transmitted infection, a history of exchanging sex for money or drugs and a history of incarceration. The reason we do this is because these infections can cause pelvic inflammatory disease. They can make it hard for women to bear babies or increase the risk of ectopic pregnancy, let alone just the infection rate.

Elizabeth: Let’s review the infection rate. An editorialist cites the fact that sexually transmitted infections have shown that chlamydia and gonorrhea rates in the U.S. in 2019 were at a 20-year high, and a lot of data emerging that during the pandemic they have gone even higher, with overall case rates of 553 cases per 100,000 and 188 per 100,000. The other thing that I think is concerning to note is that there are resistant strains of gonorrhea that appear to be emerging, and some of them that are really pretty intractable.

Rick: Right. I mean, the whole reason to screen is actually to treat asymptomatic individuals to prevent future symptomatic disease or spread as well. Despite all the information and the ways we have of reducing the risk and preventing it, we are at an all-time-high risk for both chlamydia and gonorrhea in 2019.

When you say screening for it, you can screen pretty much any of the tissue, from oral to your genital area, and it doesn’t have to be collected by a physician, by the way. It can be self-collected, and the tests we have are both very sensitive and very specific. That’s why there is no reason we shouldn’t be screening for it.

Elizabeth: Right. I guess we just need to get that information out there, right?

Rick: We are doing it.

Elizabeth: We are trying. On that note, that’s a look at this week’s medical headlines from Texas Tech. I’m Elizabeth Tracey.

Rick: And I’m Rick Lange. Y’all listen up and make healthy choices.






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