Month: April 2021

The Next Year: Diagnosis, Prognosis, and Prescription

Last week an earnest well-intended political leader said, “All it takes to beat this virus and return to normal is getting shots in arms.”

It is tempting to make this claim. Mass vaccinations are making a positive difference. The closer we get to or beat 80 percent vaccination rates, the less our risk of wide-spread recurrence of deadly disease.

But if “normal” is meant to suggest a near-term context where coronavirus is no longer a risk, this claim is over-stated.

In April 2020 tight containment and even eventual eradication of SARS-CoV-2 might still have been possible. But since then the virus has had too much opportunity to spread, strengthen, and diversify. Today it has hundreds-of-millions of use-cases for evolutionary test-drives. Most mutations will be minor and meaningless. But the virus now operates at a scope and scale where supercharged evolutionary tweaks cannot be discounted.

Given this risk it is not prudent to promise a return to normal even with the recent rate of US vaccinations, and unfortunately the recent rate is slowing.

We can credibly claim much lower risk by preparing Americans for another year — probably two — featuring five fundamental risk-management practices:

Vaccinate: As of April 25 just over 42 percent of all US residents (53 percent of those over age 18) have been vaccinated. This is already slowing viral flow in the United States. But for sustainable impacts on transmission and to slow mutations we need vaccination rates above 70 percent, the higher the better. We are still not making enough targeted and systemic investments — financial and otherwise — to encourage and facilitate vaccinations. We should also anticipate the need for booster shots on some yet to be determined cycle.

Test, trace, and contain: If twenty percent of US residents remain unvaccinated that is more than 60 million mobile mutation manufacturers scattered around the country. Among the vaccinated, demonstrated efficacy ranges from 72 to 96 percent depending on which vaccine and the profile of the vaccinated person. As a result, entirely domestic transmission and evolution of the disease will continue. These risks can be mitigated if local outbreaks (especially of new variants) are identified and effectively engaged as early as possible. This requires a much more robust multimodal testing and tracing capacity than the United States has so-far developed. South Korea continues to set the pace for testing/tracing. For cultural and constitutional reasons the South Korean model is problematic for the United States. But plenty of more targeted methods have been proven effective.

Support global mitigation: In addition to plenty of native-born variants, the B.1.1.7 variant, first identified in the United Kingdom, has accelerated transmissions and increased covid cases in the United States. Other variants have (and will) spread. The more the United States can do to suppress viral flames elsewhere, the less risk of heat-stroke or much worse here.

Reduce overall circulation: The coronavirus thrives on meeting new people in new places. Even vaccinated people — given significant but less than 100 percent viral suppression — are potential sources of transmission. Until vaccination rates exceed 70 percent and testing/tracing is much more extensive we should minimize our circulation. (Please see this and this and this.) I am guessing we need about 25 to 35 percent below pre-pandemic circulation to have a substantive impact on viral transmission. Today the United States has a national average of about 15 percent below pre-pandemic mobility levels.

Avoid interior crowds: Hand hygiene, physical distance, and masks help. But the most fertile sources of virus transmission have been over-crowded, badly ventilated, interior spaces. The more time spent with more people in any enclosed space, the higher our risk. Less time, fewer people, better ventilation (more), or staying outside is the healthier choice.

The risk of covid-related disease and death will persist. As we are seeing in Brazil and India — and can vividly recall from Wuhan, Bergamo, Queens, and perhaps your hometown — there is a very real — sometimes sudden — risk of healthcare systems being overwhelmed. In the next few years we are unlikely to eliminate the risks of covid. But we can now limit these risks to a level that will not threaten the US healthcare system. This will ensure quality care for those hospitalized and reduce wider health and economic effects.

The five fundamentals outlined above require continued investment in public health, shared discipline, and some personal restraint. Systemic failure to observe these fundamentals is likely to result in unnecessary disease, death, economic dislocation, and social turmoil. As always, we make choices.

Demand Management in Action

From a supply chain perspective, pandemic response can be conceived as a local-to-global effort to manage demand for health care. Supply chain professionals typically work to deliver more faster. But in this case, we want to deliver fewer covid patients to hospitals and slow overall deliveries.

To do this, various methods have been deployed to slow transmission and reduce virulence in case of transmission. Since January 2020 several non-pharmaceutical methods have been attempted.  Since December 2020 a handful of vaccines have started to be used.

Non-pharmaceutical practices have been applied inconsistently.  But there is evidence that transmission velocity for the virus is reduced when people circulate less overall and per-capita time spent in crowded, non-ventilated, interior spaces is reduced. 

The interaction between human circulation and viral transmission is implied by chart below.  More localized results often suggest tighter correlations.  The CDC mobility site allows data-display at the state and county level.  For even more localized analysis and mitigation possibilities, please see this report from the journal Nature: Mobility Network Models for Covid-19.


Reduced circulation is a passive way to give the virus fewer options to reproduce, slowing overall transmission.  Vaccines are an active means of fighting the virus when an individual is exposed to the contagion.  Once a large proportion of the population — or a crucial sub-population — is vaccinated, the velocity of viral transmission (and disease consequences) can be substantially reduced.

Since mid-December the US vaccination campaign has focused on health-care providers and those over age 65.  Today roughly 80 percent of the older age cohort has been vaccinated.  Hospitalization rates for this population demonstrate the efficacy of vaccinations to reduce demand for health-care.  (Please see more from The Financial Times.)

The virus will continue to evolve in order to maximize its reproductive options.  Mid-April saw more new covid cases confirmed — 5 million plus — than any prior week.  The more human circulation, the more opportunity for viral evolution. The challenge is to evolve our pharmaceutical and non-pharmaceutical practices to minimize covid’s flow.  Until we achieve at least 70 percent local-to-global vaccination rates, interior crowds give the virus fertile incubators for finding ways around our best demand-management efforts.

Patterns suggest principles to inform practice

On April 19, the Wall Street Journal published a substantive, concise piece on the semiconductor supply chain. Please read: Why the Chip Shortage is so Hard to Overcome.

Several generalizable Supply Chain Resilience principles are articulated (but not headlined) in the WSJ piece. I bet I could find a WSJ piece from the second-quarter of 2020 reporting on the canned soup supply chain with similar language and examples. We have experienced similar patterns with sterile saline bags to pork chops to viral vector vaccines to diesel fuel to cargo containers to nitrile gloves…

In the WSJ story several principles are glossed. Three are prominent:

  • Demand Variation: Significant shifts in volume and/or velocity of demand — especially in a short period of time — will disrupt flows, usually with amplified network effects.
  • Concentration Risk: Flow channels (aka nodes, links, edges, bottlenecks, hourglass structures) both empower and constrain flow capacity.
  • Differentiated Financial Margins can decisively influence the distance and interdependencies of flow (lower margins almost always result in more fragile networks).

There are exceptions, but they tend to prove the rule.

Unfortunately, these (and other) shared patterns and related principles are not obvious to many — perhaps most (even most readers of the WSJ). There is a persistent tendency to focus on supply chain “species”, rather than shared ecosystems of demand and supply. This is an understandable, but insufficient angle on reality. It is an approach that often reduces interventions to versions of whack-a-mole. Species abide in ecosystems. Fitness requires attention to specific and system-level characteristics.

One in 884 million

I received my first dose of the Moderna vaccine on April 17. With this jab I joined just over 131 million residents of the United States — and 884 million fellow humans — who have been vaccinated against covid in the last five months. Among my U.S. age cohort (over 65) about 80 percent have now received at least one dose. My second dose is scheduled for May 15.

On January 18, 2021 I registered with my regional (multi-county) public health agency to be vaccinated. Two weeks after this initial online sign-up I was asked to complete a survey to assess my vulnerability and priority. Other than being over 65, my risk of contagion was low. I have been largely self-isolating since early March 2020.

On March 7 my registration information was transferred from the regional public health agency’s database to the state parent-agency. The transition was not complicated. I was asked to complete a more detailed online vulnerability survey. I began receiving weekly “updates” basically confirming I was registered and warning of an extended wait.

On April 12 I received an email from the Centers for Disease Control asking me to register with the Vaccine Administration Management System (VAMS). After doing so I was able to view vaccination venues within 10, 20, and 50 miles of my zip code. For the first two days the only open slots “available” were May and June clinics scheduled to be hosted in Tajikistan, China, and Japan. It is my impression that personnel associated with my state (e.g., National Guard units) are deployed in these locations. I did not book a flight to Shanghai.

On the third morning after registering with VAMS I logged on, checked availability, and found many slots available for a nearby vaccination clinic to be hosted in two days. I chose a 10:10 to 10:20 appointment. I arrived at about 9:40 passed a temperature check and was given a number. There were four others in front of me. After my jab I waited 15 minutes. No after-effects, not even a sore arm. I departed the venue about 10:10. I was a bit more tired than usual that afternoon, but cause was unclear.

I have been self-consciously compliant, but passive seeking vaccination. I assisted my wife to be more proactive. She received her two vaccinations from a local chain pharmacy in late February and March. She now has maximum immunity, estimated at over 90 percent. But given my minimal vulnerability — and my professional roles — I have been curious to see when and how the public health system would get to me.

In early January I perceived that by the end of April or early May it would be possible to begin vaccinating the general population. In many ways that threshold is already being crossed. In early January I was also concerned that variants would accelerate disease and death by mid-March. The variants have increased hospitalization rates, but later and — so far — less precipitously than I expected. Meanwhile U.S. vaccination rates have been a bit faster than I expected.

I am happy that variants have been three or more weeks slower to dominate than I expected, while the pace of vaccinations is at least two weeks faster than I expected. In something as dynamic as this pandemic, such marginal differences can have magnified outcomes.

Near-term Vaccine Flows

The recommended pause in administering the Johnson & Johnson vaccine will have modest near-term network-level impacts. For a host of reasons, J&J has not been expected to begin releasing large numbers of doses until late April and May. This week (April 12-17) the J&J allocation for states was sized — pre-pause — at about 700,000 doses compared with almost twenty million doses for the combined Moderna and Pfizer vaccine flows. Below is how Bloomberg has estimated production outputs. J&J is continuing vaccine production. If and when J&J is un-paused total flows will catch up.

Michigan’s Message?

As U.S. covid cases, hospitalizations, and deaths continue to climb, the situation in Michigan is cause for particular concern. Michigan hospitalizations have surged sharply since mid-March. Michigan has a higher proportion of the B.1.1.7 variant circulating than any other state. Early observations have found that B.1.1.7 and two other variants are more easily transmissible. Some credible early studies have found an increased probability of death as B.1.1.7 circulates more widely. There may be indications that younger people are more susceptible to contagion and disease from B.1.1.7 than earlier versions of the virus, but the most rigorous studies so far available do not confirm such observations. While the ambiguity is real (a persistent feature of this novel coronavirus), from the perspective of demand and supply networks, the variants might be said to have new “features” that are more engaging to a wider demographic. The result, unfortunately, is increasing hospital traffic and demand for clinical care. This is happening even though nearly one-fifth of Michigan residents — and nearly one-third of adults — have been vaccinated. Demand management is in a race with demand velocity.

Source: Michigan Department of Health and Human Services