Preserving flows while omicron grows

On Christmas eve about 700 commercial flights serving US routes were canceled, on Christmas day another 900 plus, yesterday (Sunday) there were more than 600 cancelations (more and more). As of 5AM (eastern) today, 700 plus flights have been scrubbed. This is part of a significant global uptick. Positive covid tests for pilots, flight attendants and other air transport personnel are being blamed for a large portion of cancellations. The highly contagious omicron variant is suspected in a sharp increase in confirmed cases among flight crews.

There is no reason to assume that infections are less prevalent among workers in other production, processing, distributing, and delivery sectors, for example: health care, public water systems, food, fuel, pharmaceuticals, medical goods, and related freight operators.

Recognizing the fast moving threat, on December 23 the CDC amended its isolation guidance for Health Care Personnel. The detailed amendment includes this summary:

In general, asymptomatic HCP who have had a higher-risk exposure do not require work restriction if they have received all COVID-19 vaccine doses, including booster dose, as recommended by CDC and do not develop symptoms or test positive for SARS-CoV-2. The duration of protection offered by booster doses of vaccine and their effect on emerging variants are not clear; additional updates will be provided as more information becomes available.

This change recognizes that given omicron’s transmission velocity and ability to evade prior immunity, lengthy periods of workforce isolation or quarantine could decimate health care capacity.

The CDC continues to recommend that workers who are not Health Care Personnel quarantine for seven to ten days after potential exposure to a confirmed case. This differentiated approach is intended to minimize risks of transmission. The more contagious people circulating, the higher the risk of rapid and widespread transmission.

Given the wanton velocity of omicron’s transmission patterns, is this prudent principle still appropriate?

Early assessments suggest that omicron is much more contagious than prior variants, with case counts doubling every three days or less (here and here and here). If these early findings are accurate, there is no reason to assume that other sectors and flows do not face capacity risks similar to those facing health care. CDC decision-makers are more personally familiar with the work-force capacity risk in health care. But just as physicians, nurses, and medical technicians are needed, so are food processors, distribution center selectors, truck drivers and the other folks who keep us fed, fueled, and functioning.

Without this network of networks — these interdependent workers and functions — continuing to operate at scale, holiday travel is not the only flow about to be disrupted.

The revised CDC recommendation for Health Care Personnel recognizes that IF a worker is vaccinated/boosted and IF a worker is asymptomatic, then even with a high-risk exposure “work restriction” is not required… unless s/he tests positive. Other long-proven transmission mitigation measures (e.g., masking, physical distance, ventilation, etc.) are encouraged. Given omicron’s transmission rate, there is a reasonable case for this same flexibility being extended to workers in other sectors.

These last few days of troubled air travel signal that even more flexibility may be needed soon. Most of the pilots and flight attendants testing positive are vaccinated and asymptomatic. Many are boosted. But because they are testing positive, CDC recommendations and related industry policies have resulted in at least seven days away from work. The result is canceled flights, reduced flows, and other predictable bottlenecks and back-ups. The air travel industry is requesting no more than five days of isolation.

If omicron is as contagious and effective at evading immunity as early studies indicate (more and more and more), even five days isolation could erase an untenable proportion of flights, freight deliveries, food processing, and more high volume, necessarily high velocity flows. Temporary and quickly recurring loss of velocity can have long-term and wide-spread disruptive impacts on such networks… as we have often seen in the last two years.

If 90-some percent of omicron-related infections and re-infections result in mild symptoms or no symptoms, when, where, and how should asymptomatic, vaccinated, and boosted workers be able to continue without isolation or quarantine?

I certainly want to acknowledge each of the “ifs” noted above. But now is the time to ask and answer, if then: what, when, where, and how?