Dean's Notes

I began writing these comments as I returned from vacation a week ago on August 8, but stalled during the flight back from Amsterdam, breaking the streak of 126 consecutive weekly postings. With the pandemic stalled, the pace of notable public health events has slowed somewhat, but this last week has brought ample fodder.

At last, I can write that Colorado’s epidemic curve has finally turned downwards after its many-week plateau. The Colorado Department of Public Health and Environment lists last week’s hospital count as 243, down from 268 for the prior week and well below the plateau’s counts in the low 300s. Test positivity continues to decline, now at 7.7% versus a previous high over 13%, and case numbers are also falling. Our modeling had projected an inevitable fall in the curve, though the decline was delayed by over a month from June projections. An explanation for the month-and-a-half-long plateau remains elusive, but it must reflect countervailing drivers and brakes on the epidemic curve.  

What happens next? The Institute for Health Metrics and Evaluation (IHME) projects a continued downward trend into October. The BA.4/BA.5 surge has passed, leaving us well positioned for the start of the school year. Stating the obvious, what happens next depends on the next variant that is able to thrive under current levels of population immunity across the globe. There are variants of interest and of concern, but no headliners. The Centers for Disease Control and Prevention lists only familiar strains as variants of concern. The BA.2.75 variant has been identified in wastewater in Colorado, but public health implications are uncertain. We are heading into a lull without certainty as to when there will be a storm. 

The value of wastewater surveillance was documented once more with last week’s report of identification of the polio virus in New York City, following a case of paralytic polio in an unvaccinated Rockland County resident in July. There has not been a case of polio caused by the wild polio virus that originated in the United States since 1978. The new case and the presence of the virus in wastewater are concerning, particularly given the low rates of polio vaccination in some populations, running as low as 60.3% in Rockland County, New York. The arrival of the polio vaccination was a miraculous and liberating event in my childhood. The pandemic has reduced the rate of childhood vaccination globally, including for polio. Public health services have been diminished and vaccinations have been tarnished by politics and misinformation. We don’t need to pile avoidable cases of polio onto the public health workforce.     

Last week brought the new recommendations from CDC concerning measures to reduce transmission of SARS-CoV-2. The CDC acknowledges the changing context of the pandemic with presently high levels of immunity from vaccination and past infection, and the availability of therapeutics. From the CDC summary: 

What is already known about this topic?
High levels of immunity and availability of effective COVID-19 prevention and management tools have reduced the risk for medically significant illness and death.

What is added by this report?
To prevent medically significant COVID-19 illness and death, persons must understand their risk, take steps to protect themselves and others with vaccines, therapeutics, and nonpharmaceutical interventions when needed, receive testing and wear masks when exposed, receive testing if symptomatic, and isolate for ≥5 days if infected.

I began this commentary as I returned from a week of cycling in Flanders, the northern Flemish-speaking part of Belgium. Perhaps, Belgium, the Netherlands and other countries in Europe should be exemplars for the United States in using bicycles for transportation. While not quite so developed as in the Netherlands, the Belgian infrastructure for assuring the safety of cyclists is impressive: paths for cyclists are marked; there are separate traffic signals for cyclists in many locations; and drivers are watchful and respectful of cyclists. We needed a few days to learn that the cars had stopped for us and we should proceed to cross the highway. This does happen in Colorado as well, but without enough consistency to bring trust.  

Some further observations about possibilities: e-bikes of all sorts were common—transporting children and all manner of goods. By observation, older riders were almost all using e-bikes and moving quickly. In fact, one of our taxi drivers expressed concern about their safety because of the speed of e-bikes. In the United States, few locales have the needed level of infrastructure to emulate Belgium or the Netherlands. Some cities are continuing to refine cycling infrastructure and taking steps to encourage cycling. Denver implemented an e-bike assistance plan that was quickly exhausted and a state e-bike program is anticipated for January. Advancing cycling as a mode of transport is one step towards reducing greenhouse gas emissions. We have the Netherlands, Belgium, and other countries as models. 

And, before leaving the topic of cycling—a book recommendation for those who ride: The Rider by Tim Krabbé, a Dutch rider and author. The book is his reverie during a single race, recording his thoughts about the happenings during the race and about cycling. I was charmed when I first read it long ago and immediately bought copies for all my cycling friends.  

Two years ago, I helped to organize an extremely well attended National Academies workshop on airborne transmission of SARS-CoV-2. The first of three follow-up workshops on control of SARS-CoV-2 transmission in indoor environments will be held on Thursday. More information and registration can be found on the NASEM website.

Jonathan Samet, MD, MS
Dean, Colorado School of Public Health