by Patrick Bernet, PhD

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Florida’s 2020 COVID-19 experience offers many lessons regarding how the social, demographic, political, and economic attributes of communities affect their vulnerability to pandemic health threats. The timing, size, and geographic locus of infection waves is strongly associated with those community characteristics acting directly and through interaction with one another in ways that can either insulate or amplify their consequences. Starting with a look at community age structure, this three-part mini-series explores the impact of race and ethnicity, then political partisanship in upcoming posts.

This series summarizes findings from studies of Florida COVID-19 outcomes (read “Trends in Florida’s 2020 COVID-19 Experience”). Set at the county level, the focus on characteristics of the community as a whole identifies risks and protections jointly shared by all residents. Counts of all 2020 infections, emergency department (ED) visits, hospitalizations, and deaths were accumulated by county, month, and patient age cohort. Outcome rates were assessed relative to peer counties in statistical models adjusted for each counties’ unique set of demographic, socioeconomic, geopolitical, age composition, and 2020 presidential voting characteristics.

Overview

Florida experienced 1,352,782 COVID-19 infections; 107,370 ED visits; 64,854 hospitalizations; and 22,506 deaths in 2020. The age distribution of infections brings together one of the most-infected cohorts of young adults in the US with one of the largest collection of retirees, with those aged 65 or more comprising 21% of the state’s population. (See Figure 1) 

Figure 1: Summary of statewide COVID-19 cases.

Source: Author’s analysis of COVID-19 case data for 2020 from the Florida Department of Health, using American Community Survey population demographics to compute rates per 100,000.

The high infection rates of younger cohorts have broader consequences for the entire community. Comprising 13% of Florida’s 21 million population, people aged 25-34 had 18% of all COVID-19 cases, making them the most-infected cohort. The size of this cohort measured as the proportion of all county residents was also strongly associated with COVID-19 rates. Counties with higher proportions of people aged 25-34 had significantly higher infection rates among all ages. Each one percent increase in the proportion of a county’s 25-34 population was associated with an additional 337 infections per 100,000 during 2020 according to the study. This is visually demonstrated in an upward sweep of county data points in panel A of Figure 2. When ages 25-34 constitute less than 10% of the population, infection rates averaged 4,000 per 100,000. But when that proportion exceeds 14%, rates routinely top 7,000. Being over one generation away does not insulate those aged over 64, who experience an additional 292 infections per 100,000 for each one percent increase in the 25-34 population share (panel B in Figure 2).  

Figure 2: COVID-19 infections and the population proportion of those aged 25-34.

Source: Author’s analysis of COVID-19 case data for 2020 from the Florida Department of Health, using American Community Survey population demographics to compute rate per 100,000. The horizontal axis in both panels represents the proportion of the population between the ages of 25-34. It does not report this cohort’s infection rate. The vertical axis in Panel A represents total (all age) infection rates, and in Panel B, it tracks infection rate for those over age 64.

The strength of intergenerational spread demonstrated above figures prominently in a natural experiment that reveals the health consequences of policy decisions involving school openings. Prior to August, the same upward sweep linking county elevated COVID-19 rates with populations proportions aged 25-34 can also be detected for proportions aged under 15 (blue circles in panel A of Figure 3). Even less well defined is a positive but statistically insignificant rise in that youngest age cohort’s own infection rates (red dots). 

Infection rate increases between June and September coincide with the governor’s decision to re-open in-person schools. Three south Florida counties — Palm Beach, Broward, and Miami —  successfully fought to delay. During June-July, these three counties had above-average overall infection rates, especially Miami. Similarly, infection rates in 0-14 ages were also above-average. But in August and September, infection rates for these three counties dropped significantly relative to other counties where in-person schools were re-opening. COVID-19 infections rates for the total population and for those under 15 visibly drop relative to their peers in panel B of Figure 3. That this rapid turnaround occurred in Florida’s three largest counties with a combined population over 6 million indicates the power of policy decisions, and the speed of response. It appears the decision to delay in-person classes saved these counties thousands of infections and associated deaths. 

Figure 3: Age Cohort population share and % COVID-19 infected. Florida 2020.

COVID-19 Infections & Population Aged 0-14

Source: Author’s analysis of COVID-19 case data for 2020 from the Florida Department of Health, using American Community Survey population demographics to compute population share of each cohort and the percent of age cohort infection. Case data reports patient age, which is used to aggregate outcome counts in each cohort.

Accurate and objective information that discloses all relevant risks is an important tool in pandemics. While studies like this attempt to address that gap, policy makers remain uncharacteristically mute regarding negative consequences. In a state with a high proportion of seniors, there are structural ageism implications of policy decisions that increase COVID-19’s toll on seniors. Omission of critical information in a pandemic deprives residents the ability to make informed decisions for their health and that of their communities.

RECOMMENDED:

• Association of Age-Specific 2020 Florida COVID-19 Rates With Population Age Distribution and Presidential Preference

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Patrick Bernet, PhD, is an Associate Professor at Florida Atlantic University. Dr. Bernet researches pregnancy outcomes, focusing on disparities, program cost effectiveness, and the impact of bias on health from the perspectives of behavioral economics and financial analysis. He also studies the demographics of the COVID-19 pandemic. In addition to Dr. Bernet’s research, he also serves on maternal and child health committees in both Broward and Palm Beach counties and is a volunteer Medicare insurance counselor.