Sept. 9, 2020
Dear Members of the Baylor College of Medicine Community,
It is hard to believe that we have been living our COVID-19 lives only since about last March. It has been a shade over six months, but it seems so much longer than that. As I pause to reflect on our shared journey over that time, the first two words that come to mind are “pride” and “humility.” I mean pride in the positive sense: that which is earned and justified. Humility reflects how far we yet have to go.
But first, the recent numbers. There is little drama here this week, and let us all hope it stays that way. Most of the national and state numbers are improving. Regarding our Houston regional specific numbers, please refer to prior posts for a more complete explanation of the key TMC metrics. In short, our R(t) value (the estimate of viral infectivity) is down below 1.0 again, which is good. New case rates in Harris and surrounding counties are slowly drifting down, albeit more slowly than anyone would like. Recall, we want this number to be less than 200, about one fifth of its current level. These two data points demand a word of caution: The R(t) and new case numbers are not independent variables, and both are impacted by data reporting issues from the state. I do not yet have confidence in the validity of these two metrics. The reporting backlog seems to be improving, but there are still open questions as to when a new case is added into the state’s database (Date of specimen collection? Date of data entry?), and how duplicate entries are managed.
The TMC’s third monitoring metric – test positivity percentage – currently sits at goal at 5 percent and this is a reliable number as it is based on data directly flowing from TMC institutions. Harris County’s positivity rate is also trending down, currently at 9.5 percent. Test positivity rate is a very rough estimate of disease incidence in the community. In order to reopen schools and relax other restrictions, we need to have a low disease incidence (rate of appearance of new disease) and prevalence (total amount of disease in the community at any given time).
For the past couple of weeks, I have started to focus on the TMC new COVID-19 hospitalizations. From a high of about 360 admissions per day in early July, this dropped to 88 per day two weeks ago, but inched up again last week. It now appears to be trending back down again. Keep your eye on this number if you are looking for a “Labor Day” effect. Recall, viral exposure leads to a sequence of events. The virus incubates in the respiratory tract. In at least some people it produces disease severe enough to require hospitalization. This process from exposure to hospitalization takes on average 7-14 days. I will be very curious to see what the new hospitalizations are on Sept. 21, and if they are rising or falling. I predict they will be higher. Fourteen days after Memorial Day, we saw an increase in new community cases of about 65 percent (from 285/day to 470/day), and they kept on growing from there. New hospitalizations were not far behind. Two weeks after July 4th, new cases increased by an almost identical percentage (64 percent from 1400/day to 2300/day).
In retrospect, things started to improve from mid-July forward. It is a shame we cannot rely on the new community cases data, as this is probably our best canary in our coronavirus coal mine, but watch the new hospitalizations. If they are trending up, we could be headed for another disease surge. Perhaps – hopefully – enough people have embraced masking, distancing and safe practices at this point that it will dampen the Labor Day impact.
All projections are dicey. Like trying to predict if Hurricane Laura will hit Houston, there is no simple model, and things can change quickly. We all crave certainty, which no one can offer at this point. Which brings me back to the theme of humility. But first, pride.
If you step back and reflect on the expansion of SARS-CoV-2 (the pathogen) and COVID-19 (the disease) related knowledge over the past 6 months, it is stunning – almost explosive. In very rapid fashion, we – scientists and clinicians – have learned a ton about the basic genetics, lifecycle, evolution and structure of the disease. The cellular binding receptors have been identified, and we have some understanding of the human body’s complex and variable response to infection. We have a well-defined understanding of the course of the disease, and we have developed partially effective treatment protocols and novel drug therapies. We are well down the path of developing multiple vaccines, while systematically assessing their safety and efficacy. We are beginning to understand the long-term complications of the disease. And – notably – we have accomplished this while keeping providers safe. For all our failings, and recognizing many things could have gone better, we should be proud. Our research and care delivery system performed admirably.
However, there is a consequence to this rapid growth of knowledge. Dr. Charles Burwell, a former dean of the Harvard Medical School, in an address famously told a class of new medical students, “half of what we are going to teach you is wrong, and half is right. Our problem is that we don’t know which half is which.” So it goes with COVID-19 knowledge. What we think we know today may prove wrong tomorrow. Treatments that seem promising in case reports, case series and meta-analyses fail to demonstrate benefits in randomized controlled trials. New basic science discoveries will drive the development of treatments not yet contemplated. This is not a flaw in our system – it is our system working as intended and working very well.
Now, humility. SARS-CoV-2 has humbled us along the way. As we contemplate returning children to face-to-face classrooms, one great example of how our knowledge has evolved relates to how the virus impacts children. In the few months we have been battling this pathogen, the thinking on involvement in children has changed dramatically.
When COVID-19 first appeared on the scene, the common thinking was that children were not really susceptible to infection. They rarely contracted the disease, and if they did, it was usually mild.
Very shortly thereafter, it was discovered children with COVID-19, as a delayed complication, may develop a condition resembling Kawasaki’s Disease, a rare disease of unknown etiology that results in diffuse inflammation throughout the body and is a significant cause of acquired heart disease in children. Although still rare, COVID-19 could no longer be considered an entirely benign pediatric condition.
Weeks later, the thinking evolved. Children were contracting COVID-19, and being hospitalized, with the most severe cases unfortunately rivaling the adult experience. However, the severe cases seemed to be mainly confined to obese adolescents.
More recently, data from a sleepover camp in Georgia showed COVID-19 spreads with surprising ease among children of all ages (campers were aged six and above).
Finally, today. It is clear children do contract COVID-19. The American Academy of Pediatrics summary of state reporting data on children clearly indicates children become infected with the virus (over 476,000 cases to date, almost 10 percent of the total number of documented infections). However, thankfully, hospitalizations and death are uncommon. The risk of spread from asymptomatic children to adults remains unsettled.
Now as we contemplate returning tens of millions of children to school – an educational, emotional, social and economic imperative – think about the above evolution and how reasonable recommendations may have changed from then to now, based on what we thought we knew. Early on, it might have been rational to reopen schools with minimal precautions. Based on current knowledge, we need to plan cautiously, with adequate protection for children, teachers and staff. We also must consider and manage the risk to vulnerable adults living with school age children.
There are other examples of how knowledge has evolved. From “don’t wear surgical masks, we need to save them for health care workers and first responders” to “everyone should be wearing a cloth mask.” We used to think transmission from inanimate objects was a significant risk. It is now clear this is not a major mode of transmission (you should still wash your hands regularly, and keep them away from your face). I will repeat. The evolution of evidenced-based guidelines is not a flaw in our system – it is our system working as intended.
We need to balance these two sides of our coin: pride and humility. By embracing both, other virtues follow. We will have the confidence to move forward, making timely decisions with incomplete information. We will have the maturity to change our practices and behaviors as new evidence emerges. Importantly, we will display charity and patience with leaders in our civic, medical, educational and business communities who are acting in good faith to protect people and mitigate the impact of this novel global disaster.
James T. McDeavitt, M.D
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