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. A transcript of the podcast is below the summary.
This week’s topics include excess deaths due to COVID-19, the probability of infection after exposure to COVID positive close contacts, falls in the elderly, and herd immunity development.
0:51 Prevalence of COVID infection in Spain
1:51 Seroprevalence across the country
2:52 As early as 8 weeks, titer falls
3:20 Excess deaths due to COVID
4:20 Substantial variability in states
5:19 Other excess deaths not directly related
6:20 Reliable way of estimating
6:41 Probability of development of symptoms
7:40 Respiratory symptoms, cough or fever
8:46 Almost 3/4 under 60 had no symptoms
10:15 62% women
11:15 Very robust study no better than usual care
12:17 Awareness of falls helped?
Elizabeth Tracey: What does excess death data tell us about the true toll of COVID-19?
Rick Lange: What’s the probability of symptoms and critical disease after COVID infection?
Elizabeth: How can we prevent falls in elderly people?
Rick: And is herd immunity in the cards for COVID infection?
Elizabeth: That’s what we’re talking about this week on TTHealthWatch, 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: In keeping with what seems to be becoming a tradition, Rick, why don’t we start first with all of our COVID material? We’ll end with this piece in the New England Journal of Medicine on preventing falls. You actually suggested one of these studies for this week. That’s in the Lancet. Why don’t you talk about that one?
Rick: Sure. This was a look at, actually, the prevalence of COVID infection in Spain and this is a nationwide population-based seroepidemiological study. I teed it up as, “Is herd immunity in the cards?”
Since we don’t have effective treatment for COVID infection, the 2 major strategies are, can we have herd immunity? What that means is 50% to 70% of the population has already been infected with COVID infection and their antibodies will protect the rest of us. Or the second is vaccination. What this study did was it looked at the evidence of COVID infection nationwide in Spain and they looked at over 35,000 households — over 61,000 participants. They did a very detailed questionnaire on the history of symptoms compatible with COVID-19 and also risk factors, and also they did two different types of antibody testing. One is a point of care with a finger stick and the other is they drew blood.
The seroprevalence across the country was only 5%. That does not get us anywhere near the herd immunity of 50% to 70%. Then they looked at really the hotspots around Madrid and Barcelona, and the seroprevalence there was only about 11% or 12%. About 90% of people that tested positive with the antigen test had ended up developing antibodies by either one of these two tests.
The last thing is they determined that about a third of the patients that were infected were actually asymptomatic. That means that herd immunity is not likely going to protect the majority of people across the globe.
Elizabeth: Not right now. We’ve got a long way to go to really achieve herd immunity. I guess one of the questions that occurs to me — and this is not something that’s going to be within the scope of this study — has been this rather curious phenomenon we’ve observed relative to the development of antibodies, and that, in fact, some people who have had the infection really have had a pretty poor immune response relative to that production.
Rick: Right. The immune responses — as measured by the titer of antibodies — really varies across the population and there’s some evidence that suggests that even as early as 8 weeks after active infection that the titers of antibody decrease substantially. So there’s still a lot more we need to learn.
Elizabeth: I absolutely agree and I would finally note that one thing I’ve seen this week has been the identification of a T cell response and a subset of T cells that are pretty critically important, they think, and may in fact be activated even in people who are lacking in antibody response. I think we’re going to hear more about that one.
Let’s turn to JAMA Internal Medicine. I thought this was a pretty important study. It’s taking a look at the estimate of excess deaths associated with COVID-19 in the United States between March and May of this year. What they did was look at public health data of the entire U.S. population using data from the National Center for Health Statistics.
During that period of time, there were what they called 122,300 excess deaths that would typically be expected at a comparable time of year for the U.S. Of that number, the 122,000+, 95,000+ were officially attributed to COVID-19, so 28%. That number of excess all-cause deaths was 28% higher than the official tally of COVID-19-reported deaths during that time period.
They also note that there was substantial variability between states in the difference between these COVID-19 deaths and the estimated burden of excess deaths. They attribute that to, of course, testing, but also reporting. And I would say that some of this reporting data we’re seeing that also when we’re taking a look at racial differences, for example.
They note that Connecticut and North Carolina were missing mortality data and so they were excluded. Connecticut, of course, was a place where there was a lot going on during this time period, so I’m concerned about this disparity.
Rick: People like to refer to this as kind of the official tallies of COVID-19-related deaths. This has certain problems. One is obviously the sensitivity of the testing. The other is, as you mentioned, there’s reporting difficulties. With large outbreaks, there’s just unavoidable delays in even compiling death certificates and ascertaining causes of death. And early in an epidemic, one may just code it as a pneumonia and not realize it’s COVID-related.
Just as important, now there are other excess deaths not directly related to COVID, but indirectly. For example, people that have a stroke or heart attack but won’t come to the hospital because of concerns about COVID — well, that’s still a COVID-related death, believe it or not.
This study confirms another one that shows that even the official tallies underestimate the COVID-related deaths by about 28% to 30%. You can imagine that in other developing countries, or countries where testing isn’t available, or they’re not as rigorous in terms of recording things on death certificates, where the underreporting is even more magnified.
Elizabeth: Exactly. The authors identify, of course, some of the reasons there could be this disparity, including, of course, intensity of testing, and the guidelines — as you’ve already noted — on the recording of deaths that are suspected but don’t have a laboratory confirmation, and finally, the location where someone dies. Because if they’re unattended at home, the likelihood is pretty low that we’re going to say, “Hey, was this COVID?”
Rick: Yep, and so many epidemiologists feel that looking at excess deaths is a much more reliable way of ascertaining the effects of COVID than just doing these official tallies. Based upon this data, I would tend to agree.
Elizabeth: So then, of course, we are drawn to the conclusion that almost a third more deaths are taking place relative to COVID-19 than are officially being reported.
Rick: So Elizabeth, let’s talk about the next one. That’s the probability of symptoms of critical disease after COVID infection.
Elizabeth: This is a preprint. This is not peer-reviewed.
Rick: I’ll talk about the results of this particular study and then we’ll talk about some of the difficulties, especially with a non-peer-reviewed article. This is a report from Italy in conjunction with a medical school here in the U.S. that looked at the probability of developing symptoms and critical disease — does the person require an ICU stay or did they die — after COVID infection.
They did this based upon serologic data that was obtained in Italy. They identified almost 5,500 close contacts of people that had confirmed COVID infection. It’s a person that lives in the same household or they engaged face-to-face with a short distance for a long period of time. Some of these close contacts had viral testing done looking for antigen, some had antibody testing done, some had both done, and then they ask them whether they had symptoms.
Now, the interesting thing is the only symptoms they ask them about were respiratory symptoms like cough, shortness of breath, or fever. Now, you and I both know that there are a myriad of symptoms — loss of taste, loss of smell, myalgias, fatigue — and what they determined, about 50% of them ended up having evidence of infection. A 50% infection rate from close contact is about threefold higher than what’s been previously reported. Seventy percent of the people were asymptomatic.
Then they looked at it by age. The probability of developing symptoms increased with age. Those less than 20 years of age, only about 18% were symptomatic. Those over 80 years old, it was closer to 70%. The number that presented with critical disease was also very similar. Overall, about 3% of people required an ICU stay or a hospitalization. Those that were under the age of 60, about 0.5%. Those over the age of 60, it was about 7%. By the way, over the age of 80 it was closer to 15% or 25%.
Elizabeth: Right, and of course that’s consonant with everything else that’s been coming out about this. I thought it was really interesting it was 74% of all infected individuals less than 60 years of age did not develop symptoms, almost three quarters of them.
Rick: Again, it’s how they very narrowly defined symptoms. I’m not sure I’d put a lot of weight on these specific numbers, but I do think there was a gradation by age with regard to the presence of typical respiratory symptoms and fever, and also by the criticality of the disease.
Elizabeth: Clearly it points to a number of things, including strategies to protect older people and potentially targeting them for vaccinations when one becomes available. Since we’re talking about older people, let’s turn to the New England Journal of Medicine. This study was a negative study, a little bit disappointing, or actually a lot disappointing for me.
They created a really pretty comprehensive strategy, in my mind, for trying to reduce falls, and we know that falls are major contributors to complications and death in older people. As part of a PCORI study, they enrolled 86 primary care practices across 10 healthcare systems. They had community-dwelling adults 70 years of age or older who were at increased risk for fall injuries as the cohort that they selected from.
Their primary outcome was a first serious fall injury and a secondary outcome was self-reported falls. The intervention group was 2,802 participants and a control group, which was different practices, was 2,649 participants. Their mean age was 80 years and 62% of the participants were women, unsurprisingly, I think.
They developed this multifactorial intervention that was administered by nurses and they took a look for this outcome of falls that were adjudicated — that is, they were seen by somebody in the medical system. As I said, very disappointingly, there was virtually no difference between the intervention group and the control group with regard to fall prevention.
Rick: This was an extremely well-done study and again, as you mention, this is an important issue because among older Americans, falls are really the leading cause of injury-related deaths. The estimate is that 1 in 4 older adults fall each year. Of those, 20% to 30% have moderate to severe injuries, including deaths and hospitalizations.
You would think that a multifactorial strategy using trained individuals, looking at things like modifiable risk factors and standardized protocol-driven recommendations, individualized care plans, would address this. But in this very robust study, it was really no better than usual care, which is telling individuals, “Please be careful.”
It was disappointing. It’s unusual oftentimes for the New England Journal of Medicine to publish a negative study, but this one is so important I really appreciate the fact that they made this information available to everybody.
Elizabeth: Well, you’ve identified and foreshadowed already these modifiable risk factors that these folks were assessed for. Those included impairment of strength, gait or balance, certain medication use, postural hypertension, problems with their feet or footwear, vision impairment, osteoporosis, or vitamin D deficiency, and home safety hazards.
These are all things that, gosh, we’ve talked about separately relative to fall risk, and then they developed an individualized care plan that was focused on 1 to 3 of those risk factors that each individual presented with. So it’s hard for me to speculate on what they would improve in order to actually have a discernible difference in the intervention group.
I will say that one fact I thought was really interesting in the discussion part was that the annual rates of adjudicated serious fall injuries were approximately 5% in this trial in both groups and their a priori hypothesis was that that would be 14%. They speculate that it could be that just the awareness of risk of falls, regardless of whether this individualized care plan was implemented, may have contributed to that.
Rick: And if that’s the case, then obviously we need to make individuals aware of it. We can do it in a less costly way that requires less resources [but] to be just as effective.
Elizabeth: On that up 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.