To my Patients and Friends,
Here’s some of the latest on COVID-19… I hope you find this informative.
What hasn’t been discussed
A very interesting article recently popped up in The Atlantic. It proposes a sensible explanation for the wide range of regional variations in terms of case counts and death rates we’ve witnessed in association with the COVID-19 pandemic. On the most basic level, the author suggests that not all affected individuals spread the virus equally, and that certain factors play key roles in contributing to the variable ways in which the virus spreads through different communities.
To date, there’s been quite a bit of chatter about the importance of the R0 (pronounced R-naught), which represents the contagiousness of the virus and refers to the average number of susceptible individuals expected to be infected after exposure to a person with the disease. For example, if an infected individual is expected to transmit the virus to 3 others, then the R0 is 3. Obviously, a lower regional R0 is always preferred, but there are important considerations beyond the average rate of transmission. If your head is in the freezer but your feet are in the fire, your average temperature may be just right, but that doesn’t tell the whole story.
We’ve learned from experience that contagiousness can vary significantly depending on surrounding circumstances. Infected individuals are much less likely to disperse the virus when outdoors rather than indoors, when the ambient air circulation is optimal, when physical distances are maintained, when durations of exposure are shortened, when masks are worn, and when speaking quietly rather than loudly. This dispersion factor, otherwise known as the k value, is taking front and center in our understanding of the dynamics of disease transmission. Essentially, a lower k value corresponds to a higher rate of transmission from a small number of individuals. As the author explains, “this highly skewed, imbalanced distribution means that an early run of bad luck with a few super-spreading events, or clusters, can produce dramatically different outcomes even for otherwise similar countries.” By way of example, check out what’s happening in Connecticut: dispersion rates have generally been highest in our more densely-populated cities and towns.
By embracing this newer understanding of the clustering dynamic of COVID-19 transmission and by patiently modifying our social behaviors accordingly (i.e, by continuing with safe distancing measures in general, but particularly by resisting the temptation to organize or attend larger indoor gatherings as the cold season approaches), we may more readily get ahead of this thing.
But to be clear: it’s going to be a very long winter
“Anyone who does not think this is a seasonal virus is
mistaken. And we are about to get hit tremendously
hard in the US. Everything will shut down again, I
think, this winter.”
– Dr. Michael Mina
Harvard’s Center for Communicable Disease Dynamics
“We are facing a whole lot of trouble… we have a
baseline of 40,000-50,000 infections per day. That’s a
bad place to be when you are going into the cool
weather of the Fall and the colder weather of the
– Dr. Anthony Fauci
Director, National Institute of Allergy and Infectious Diseases
October 12, 2020
“We do face the real risk of a significant third wave. It won’t
be a true third wave in a literal sense of how pandemics
course. But it will be a third resurgence in infections. I am
fairly concerned that this third iteration could be worse than
the other two in terms of the density of infections.”
– Dr. Scott Gottlieb
Former Commissioner, Food and Drug Administration
September 22, 2020
So can we successfully isolate and protect high-risk individuals while otherwise reopening and fully resuming normal activities in order to restore the economy and achieve herd immunity, as a small faction have suggested?
Well, it’s not just about those residing in nursing homes… we must keep in mind that:
- 72% of American adults are overweight or obese
- Nearly half of American adults have high blood pressure
- 13% of American adults have diabetes
- At least 48% of all adults in the U.S. have some form of cardiovascular disease
- Approximately one third of Americans are Black or Latinx
- 12% of U.S. residents live below the poverty line
The short answer: no way. If we were to take this very controversial (and unethical) approach, the death toll would be tremendous, our economy would undoubtedly suffer and our health care infrastructure would crumble.
So what about herd immunity?
The concept is simple, but getting there will be more challenging. Herd immunity arises when a sufficient percentage of individuals (typically thought to be 60%-80%) become immune to a particular contagion (either through vaccination or as a result of natural infection) such that its spread within a community becomes less likely. As discussed above, we will not be able to achieve natural herd immunity (i.e., via mass infection) without unnecessarily losing an estimated 1.3 million Americans. Therefore, an effective vaccine will be crucial. There is good reason for optimism that an effective vaccine will be released in the near future. That said, herd immunity may still be a long way off. Logistically speaking, it will be quite some time before a vaccine will be widely distributed (many experts believe it could take up to a year or longer). We also need to remember that, until there is worldwide immunity, we all remain at risk… this adds more layers of complexity. Beyond that, we have yet to understand the degree to which antibodies are protective, and for how long. We know, for instance, that reinfection is possible: a Nevada man was reinfected by the coronavirus two months after his initial infection, and his second infection was more severe. This means that booster doses will likely be necessary, which further complicates the challenge of the timely manufacturing and distribution of adequate quantities of vaccine. And if we use the annual influenza vaccine as an example, the outlook is even less clear: the efficacy of the flu shot is variable from year to year, typically averaging between 40% and 60%. This means that, even if every American were to receive a typical flu shot, only about half of us would be protected from the flu. Extrapolating, and recognizing that- for a number of reasons- many may be reluctant to receive the COVID-19 vaccine in the early phases, we still may be a long way off from herd immunity.
But there is good news
Although COVID-19 remains a significant threat, we have in fact gotten better at treating the disease, and mortality rates from the infection have decreased. With corticosteroid medications like dexamethasone and the antiviral drug remdesivir, more patients are being successfully discharged from hospitals and are returning to their lives and their families.
That’s all for now… the news these days is admittedly somewhat sobering, but it’s important to remember that we will get through this. In the meantime, be kind, keep your eyes on the ball, wear your face masks and wash your hands, practice patience, heed the science, and get your flu shots.
I’ll see you soon.
Larry Leibowitz, MD