One of the more confounding aspects of the SARS-CoV-2 pandemic is the degree to which changes in human activity and behavior (socialization between households, opening/closing of schools and/or universities, adoption of face coverings, restriction of travel between regions, opening/closing of various businesses, etc.) are responsible for the numerous waves of infections seen across geographical regions such as US states or European nations. Conventional wisdom seems to be that the main driver of regional surges is either failure to appropriately implement mitigation/suppression efforts, or, in situations where they have been implemented, non-compliance by individuals. In this scenario, regional epidemics are thought to be “controllable,” but only if the right combination of mitigation or suppression measures are implemented, at the optimal moment and for the appropriate amount of time, and only if the population were to fully comply. On the mechanistic level, the logic is straightforward, as a respiratory virus cannot spread if hosts are kept as separated from each other as possible, either physically (aka social distancing) or effectively (face coverings and hygiene measures). There is also an abundance of empirical evidence that at least the most draconian forms of suppression are very effective: the 70-day and 111-day strict lockdowns in Hubei, China, and Victoria, Australia, respectively, are famous examples. “Softer” forms of mitigation, of the variety that have become common in the US and Europe since April 2020, undoubtedly also shape the course of infections and the ensuing hospitalizations and deaths, but a closer look at the data that has been compiled over the last 10 months reveals a much more complicated and perplexing story than is commonly expressed in the media and communicated to the public by public health and government officials.
In late Spring, 2020, there was widespread concern that a few US states were “opening up too early and too much” and would face an explosion of exponential growth of cases, as had been experienced in the Northeastern states in March and April. Georgia, Florida and Texas are some of the larger states that were the focus of such attention.
“In an announcement last week, Kemp abruptly reversed course on the shutdown, ending many of his own restrictions on businesses and overruling those put in place by mayors throughout the state. On Friday, gyms, churches, hair and nail salons, and tattoo parlors were allowed to reopen, if the owners were willing. Yesterday, restaurants and movie theaters came back…Kemp’s order shocked people across the country…In the grips of a pandemic, the approach is a morbid experiment in just how far states can push their people. Georgians are now the largely unwilling canaries in an invisible coal mine, sent to find out just how many individuals need to lose their job or their life for a state to work through a plague.”
https://www.theatlantic.com/health/archive/2020/04/why-georgia-reopening-coronavirus-pandemic/610882/, (“Georgia’s Experiment in Human Sacrifice: The state is about to find out how many people need to lose their lives to shore up the economy,” Amanda Mull, 29 April 2020)
In reality, although the COVID epidemic has indeed taken a serious toll on these states, the outcome of reopening in early summer was not as catastrophic as predicted. For purposes of comparison, Fig. 1 shows the daily COVID deaths, normalized by population, for Massachusetts (which did not “reopen early”), Georgia and Florida (which did).
Even just a casual glance at the time evolution of the epidemic in these three states invites a number of questions. On 18 May, 230 days ago (as of 2 Jan. 2021), restrictions on social distancing and business closures began to be lifted in Massachusetts, yet the daily number of cases, and deaths, continued to fall, leveling off and staying relatively low for the next several months. Why? In Georgia and Florida, similar restrictions were lifted even earlier (approximately 250 days ago), and, eventually, to an even greater extent (e.g. opening of bars, clubs and university campuses, and 100% in-person K-12 instruction). Instead of a sharp, exponential growth of the epidemic, as experienced in Massachusetts and elsewhere in March, there was a more muted, drawn-out period of elevated cases and deaths, slowly falling off until about two months ago. How can this be explained? And why were these states castigated for reopening their economies and allowing people to socialize again? Some experts are now expressing regrets for the messaging from this past Summer:
“University of Minnesota epidemiologist Michael Osterholm, a member of Biden’s advisory board, said one March mistake was closing businesses in places in the middle of the country that had seen almost no cases. ‘Was it appropriate to shut down so many things back then when there was so little, if any transmission? I think you can argue now that probably was not the best use of resources … it clearly alienated the very populations that we needed to have work with us,’ he says.
The time was squandered and so was public trust. He compares the situation to hurricane warnings. People take them seriously because they are usually right. In many Midwest states, people went into emergency mode at the wrong time.
Last spring’s approach left the public full of rancor and deeply divided, with some seeing the restrictions as tyrannical and others convinced, just as wrongly, that if people weren’t ‘selfish’ the control measures would have eradicated the virus. That’s never been feasible in a country where so many people live in crowded housing and can’t afford to stay home.”
https://money.yahoo.com/pandemic-regrets-experts-few-133019805.html, (“Pandemic Regrets? Experts Have a Few,” Faye Flam, 29 Dec. 2020)
Another common belief was that eight months of pent up “COVID fatigue,” combined with increased socialization and travel during the Thanksgiving holiday period, would lead to a pronounced, and especially deadly new surge of cases. Surprisingly, this does not seem to have had a marked effect on the trajectory of the epidemic in the US:
“More than three weeks after Thanksgiving, epidemiologists and local health officials across the country are picking apart the holiday, seeking signs of the pandemic’s latest riddle: the Thanksgiving effect… Still, experts said that, in general, parts of the country that were improving pre-Thanksgiving continue to improve post-Thanksgiving, while other regions experiencing surges before the holiday continue to worsen, suggesting that any nationwide Thanksgiving effect was muted.”
https://www.nytimes.com/interactive/2020/12/20/us/covid-thanksgiving-effect.html, (“As Christmas Nears, Virus Experts Look for Lessons from Thanksgiving,” 20 Dec. 2020)
In fact, in a number of states in the Midwest and Northern Plains, cases peaked before Thanksgiving (38 days ago) and have since fallen sharply, without additional lockdown measures having been implemented (Fig. 2)!
What, then, are the conclusions we can draw from this confusing picture? The dynamics of a pandemic are complex, with an enormous number of confounding factors contributing to the timing, duration and relative sizes of peaks and troughs in the spread of the virus across the landscape. The gross effects displayed in the figures presented here and in the various COVID online dashboards are likely shaped dominantly by regional growth of community immunity, seasonal variation of the basic reproduction number (in temperate climates, for instance, all respiratory diseases strongly surge in Fall and Winter, and almost completely disappear in the Summer) and other factors over which we exert limited control. For regions with similar climatic conditions, population density, levels of economic activity and median age, the trajectories of the epidemic are strikingly alike (Figs. 3 and 4).
We would do well to avoid the hyperbole, the shaming over behavior, the pitting of “red states” against “blue states,” etc., that have characterized so much of our public discourse, and recognize that nobody is “winning” the pandemic, and reasonable, empathetic individuals will disagree on how to weigh the unavoidable tradeoffs associated with COVID mitigation and suppression efforts. Many mainstream, influential epidemiologists and public health experts understood, at the very start, the enormous complexity of the problem, the difficult tradeoffs to consider and the necessity for a balanced, level-headed approach, as exemplified in the Op-Ed written on 21 March 2020 by Michael Osterholm, prominent member of President-Elect Biden’s coronavirus advisory group:
“China and Italy have imposed near-draconian lockdowns in an effort to halt the spread of covid-19. But how and when will these two ‘test’ nations return to normal life? And when they do, will there be a major second wave of cases? If that happens, should they simply ‘rinse and repeat’?… Consider the effect of shutting down offices, schools, transportation systems, restaurants, hotels, stores, theaters, concert halls, sporting events and other venues indefinitely and leaving all of their workers unemployed and on the public dole. The likely result would be not just a depression but a complete economic breakdown, with countless permanently lost jobs, long before a vaccine is ready or natural immunity takes hold… But the best alternative will probably entail letting those at low risk for serious disease continue to work, keep business and manufacturing operating, and ‘run’ society, while at the same time advising higher-risk individuals to protect themselves through physical distancing and ramping up our health-care capacity as aggressively as possible. With this battle plan, we could gradually build up immunity without destroying the financial structure on which our lives are based.”
https://www.washingtonpost.com/opinions/2020/03/21/facing-covid-19-reality-national-lockdown-is-no-cure/, “Facing covid-19 reality: A national lockdown is no cure,” Michael Osterholm and Mark Olshaker, 21 March 2020.
It is curious that, back in March 2020, Osterholm was so willing to acknowledge the damage caused by the long-term implementation of strict virus suppression measures, but, like many experts, seems so much less willing to do so now. After 10 months, the available data provide very little evidence that the “soft lockdown” measures implemented by Western countries have actually suppressed the virus – they have largely shifted the waves to slightly later points in time. The notion that we should be able to control the virus with sheer willpower and abstention at this point seems based on wishful thinking rather than data. It is true that we are far from “out of the woods” with this pandemic, and in some regions of the world (like the UK), a more transmissible variant threatening to overwhelm hospitals may be justification for the short-term implementation of extreme measures, locally. But in regions not currently on the brink of crisis, we must be careful not to use the delusion of control to justify black-and-white moral judgements of others’ behavior that only add to the strife of this exceptionally challenging era.
Thanks to Dave Huber and Adrian Staub for helpful discussion and comments.
 https://www.nytimes.com/2020/11/09/us/colleges-coronavirus-thanksgiving.html, “Thanksgiving Will Soon Empty Campuses. Will Students Bring Coronavirus Home? Experts worry that some of the hundreds of thousands of departing students will be ‘little ticking time bombs,’” Shawn Hubler, 9 Nov. 2020.
 https://www.news-medical.net/news/20201112/Modeling-suggests-lower-COVID-19-cases-in-Lombardys-second-wave.aspx, “Modeling suggests lower COVID-19 cases in Lombardy’s second wave,” Lakshmi Supriya, 12 Nov. 2020. https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-9-impact-of-npis-on-covid-19/, “Report 9 – Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand,” Neil Ferguson et al, 16 Mar. 2020: “The more successful a strategy is at temporary suppression, the larger the later epidemic is predicted to be in the absence of vaccination, due to lesser build-up of herd immunity.”
 https://academic.oup.com/jid/article/222/7/1090/5874220, “Global Seasonality of Human Seasonal Coronaviruses: A Clue for Postpandemic Circulating Season of Severe Acute Respiratory Syndrome Coronavirus 2?” You Li et al, 21 July 2020.
 https://www.cnn.com/2020/10/23/health/masks-ihme-model-study-wellness/index.html, “Wearing masks could save more than 100,000 US lives through February, new study suggests,” Jacqueline Howard, 23 Oct. 2020.
https://www.nytimes.com/2020/12/07/opinion/covid-public-health-messaging.html, “It’s Time to Scare People About Covid,” Elisabeth Rosenthal, 7 Dec. 2020.
 https://www.forbes.com/sites/nicholasreimann/2020/07/05/maskless-parties-and-crowded-beaches-across-us-as-coronavirus-spikes-over-holiday-weekend/?sh=50e43ddc4699, “Maskless Parties And Crowded Beaches Across U.S. As Coronavirus Spikes Over Holiday Weekend,” Nicholas Riemann, 5 July 2020.
 https://www.nytimes.com/2020/07/30/upshot/coronavirus-republican-voting.html, “As Covid Has Become a Red-State Problem, Too, Have Attitudes Changed?” Robert Gebeloff, 30 July 2020.