29 December 2020

Covid-19 mitigation in the US: compliance drops, virus rages

In a follow-up to his article on applying ERM expertise to limit the spread of Covid-19, Dave Ingram reports on adherence to mitigation requirements in November, including for the key Thanksgiving holiday

Earlier this year, we described how enterprise risk management (ERM) techniques could be applied to help understand and reduce the spread of the Covid-19 virus.Dave Ingram

The basis of the analysis is monthly surveys that track the extent to which mitigation measures are implemented and observed by citizens, businesses and local institutions.

We study 21 different mitigation measures, which include wearing a mask in public, stay-at-home orders and mandatory closure of businesses.

Our ultimate objective is to develop a reliable linkage between the observations and changes in Covid-19 infections. In our analysis up to September, our efforts brought us to a regression formula that explains about 50% of the path of Covid-19.

This article updates the analysis for October and November.

Covid-19 rages in November

Infections more than doubled in the US in November after increasing about 50% in October. Data in December tells us the flattening of the curve at the end of November is but a temporary reprieve, likely brought on by reduced Thanksgiving holiday reporting, more than any underlying improvement.

Figure1: A look at the number of reported cases per 100,000 of population for three months.

Mitigations in November

Nationally the weighted average of compliance with the 21 mitigations that we track has gone from an average of 65.7% in September to 64.6% in October to 63.6% for November. When mitigations are broken out into practices within states and regions of states, there is a far greater variance in mitigations as respondents observe the results of individual states implementing changes in Covid-19 mitigations and individuals react to their personal perceptions of the level of Covid-19 danger locally.

In November, we collected 1,082 surveys from observers in 47 states and Washington, DC.

Figure 2: Average compliance for schools (k-12) that are closed or holding remote classes.

There is a significant variety of compliance levels in different states, from a high of 85% in Oregon to a low of 20% in Wyoming. In many states, school closures are a local decision and some schools opened and closed again within the month. We find no two states reflect the same pattern of higher and lower compliance among the 21 mitigations that we track.

Figure 3: National average compliance for a sampling of seven of the 21 mitigations.

Besides the effect of the seemingly small deterioration in the 21 mitigations that we track, we believe several other factors have been at work to help raise infection levels.

Foremost is the move away from outdoor activities with the decrease in the fall temperatures. Another factor that will play out in December is the Thanksgiving Holiday on 26 November.

Changes in how people are celebrating Thanksgiving

We asked participants how many people they planned on dining with on Thanksgiving this year and how many they had dined with last year. On average, there was a decrease in expected attendance of 6.7 people.

Nationwide, people reported dining with 15.2 people on average last year and expected to spend the holiday with 8.6 this year.

Compared with last year, the results were bifurcated between people who are not changing their Thanksgiving plans (33%) and those reducing participants by 80-100% (29%).

A small minority (15%) of people said they planned on increasing their gathering this year, while more than half (53%) planned on reducing the size of the gathering.

There is only a small correlation between weighted mitigation levels and the change in Thanksgiving attendance (0.19).

Among individual practices, there was also little correlation to the change in Thanksgiving attendance. The two largest positive correlations came between special restrictions in hospitals (0.30) and restrictions at hairdressers and barbers (0.25), while the largest negative correlations were with antibody testing (-0.26).

The lack of any strong connection between the mitigations overall and individual mitigations suggests there are different forces at play in how people protect themselves from Covid-19 normally, and how they treated the Thanksgiving holiday.

Though this year urban residents expected to have larger Thanksgiving gatherings (11.8) compared with suburban (9.6) or rural (7.8) residents, there was not much difference in the expected change in attendance between the three.

Figure 4: Percentage change in Thanksgiving Attendance for 2019 versus 2020. 

There is only a small correlation between weighted mitigation levels and the change in Thanksgiving attendance (0.19).

Among individual practices, there was also little correlation to the change in Thanksgiving attendance. The two largest positive correlations came between special restrictions in hospitals (0.30) and restrictions at hairdressers and barbers (0.25), while the largest negative correlations were with antibody testing (-0.26).

The lack of any strong connection between the mitigations overall and individual mitigations suggests there are different forces at play in how people protect themselves from Covid-19 normally, and how they treated the Thanksgiving holiday.

Figure 5: Thanksgiving attendance for urban, suburban and rural observers.

Mitigations and infections in California

Like the rest of the US, California experienced a spike in Covid-19 infections in November, but to a lesser extent than the US as a whole.

Figure 6: Covid-19 Infection Level: California versus US. This shows infection levels in California are significantly lower than the US as a whole, but are now around four times what they were in early October. The Governor of California has implemented regional stay at home orders.

 

Figure 7: Average mitigation compliance: California versus US. This shows the average mitigation levels in California have been higher than the US national average