Coccidioidomycosis and COVID-19 Co-Infection, United States, 2020

Alexandra K. Heaney; Jennifer R. Head; Kelly Broen; Karen Click; John Taylor; John R. Balmes; Jon Zelner; Justin V. Remais


Emerging Infectious Diseases. 2021;27(5):1266-1273. 

In This Article

Possible Risk Factors for Coccidioidomycosis and COVID-19

COVID-19 and coccidioidomycosis share certain risk factors for exposure, potentially increasing the risk for co-infection. In California and Arizona, the 2 states with the highest number of reported coccidioidomycosis cases, substantial overlap exists between county-level incidence of COVID-19 in 2020 and coccidioidomycosis in 2019 (Figures 1, 2).

Figure 1.

County-level incidence of (A) coronavirus disease (COVID-19) in 2020 and (B) coccidioidomycosis in 2019, California and Arizona. COVID-19 incidence reflects cumulative case count as of August 14, 2020 (5). Coccidioidomycosis incidence reflects annual incidence in 2019 (6,7). Shading indicates levels of incidence. Brackets indicate inclusive bounds; parentheses indicate exclusive bounds.

Figure 2.

Scatterplot of county-level incidence of COVID-19 in 2020 and coccidioidomycosis in 2019, California and Arizona. R2 = 0.259; p<0.01.

Occupational Risks

Certain occupations pose increased risk for coccidioidomycosis. Because soil disruption and dusty environments promote dispersal of Coccidioides spores, coccidioidomycosis outbreaks frequently occur among workers in the construction and agricultural sectors.[8–10] Of 47 coccidioidomycosis outbreaks reported during 1940–2015, a total of 25 (53%) were associated with occupational exposure, including 15 (60%) that were related to construction.[11] An analysis of workers' compensation claims found that the incidence of coccidioidomycosis related to occupational exposure nearly quadrupled in California during 2000–2006, the highest rates seen among construction and agricultural workers.[12]

Continued in-person work within the construction and agricultural sectors, which are considered essential occupations, also increases risk for COVID-19. In the United States, an estimated 8% of construction workers have had workplace exposure to the causative agent of COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), at least monthly, and nearly 60% of the construction labor force has ≥1 risk factor for severe COVID-19.[13,14] Agricultural workers might also have heightened risk for COVID-19 because of high workforce turnover, shared transportation, and overcrowded living quarters that are often shared with other workers, multigenerational families, or both.[15–19]

Incarcerated Populations

Incarcerated persons have a high risk for exposure to Coccidioides spores and SARS-CoV-2. Prisons and other facilities, such as immigration detention centers, are often in isolated areas with high environmental dust concentrations that can place inmates at higher risk for Coccidioides infection (Appendix In addition, crowding, unsanitary conditions, and poor ventilation in carceral environments contributes to the rapid spread of communicable respiratory diseases like COVID-19.[20] Researchers have documented COVID-19 outbreaks among fire-fighting crews composed of incarcerated persons;[21] similarly, researchers documented 7 coccidioidomycosis outbreaks among such fire-fighting crews during 2000–2017.[22] During 1940–2015, a total of 5 (11%) reported coccidioidomycosis outbreaks were among incarcerated populations.[11] During 2007–2011, a total of 19% of coccidioidomycosis cases in California were among incarcerated persons.[23] More than 25% of California Department of Corrections and Rehabilitation facilities, including Lompoc Prison Complex (Lompoc, CA, USA), where a COVID-19 outbreak infected >1,000 persons,[24] are in regions with high coccidioidomycosis incidence.[25]

Researchers have documented several outbreaks of COVID-19 in carceral facilities (Appendix). During January 21–April 21, 2020, a total of 82% of reporting state and territorial health department jurisdictions reported confirmed COVID-19 cases among incarcerated or detained persons (including 4,893 reported cases and 88 deaths) or staff members (including 2,778 reported cases and 15 deaths).[26] COVID-19 outbreaks affecting >1,000 persons have occurred among incarcerated persons and staff working at carceral facilities in states from California to New York (Appendix).

Racial and Ethnic Minorities

Substantial racial and ethnic disparities exist in COVID-19 and coccidioidomycosis infection rates. Persons of Black and Latino heritage are at heightened risk for these infections. In California as of February 2021, Latino persons comprise 39% of the total population but account for 55% of COVID-19 cases.[27] In the United States, COVID-19 incidence and death rates in counties with predominantly Black populations are significantly higher than in counties with predominantly white populations.[28] In addition, Latino persons comprise 39% of the California population but 47% of its coccidioidomycosis patients; in the same state, non-Hispanic Black persons comprise 6% of the population but 9% of coccidioidomycosis patients.[3]

Numerous societal inequities (including racism and discrimination, economic and educational disadvantages, and lack of healthcare access) contribute to higher pathogen exposure and infection rates among Black and Latino populations.[29] In the context of the COVID-19 pandemic, social distancing might be more difficult for persons of low socioeconomic status because of their overrepresentation in essential occupations, elevated risk of living in densely populated homes and neighborhoods, and higher numbers of multigenerational households.[15–19] For example, 55% of Latino and 48% of Black persons work in essential jobs, compared with 35% of White persons.[30] Disparities in coccidioidomycosis rates might also be caused by the disproportionate numbers of Black and Latino persons who are incarcerated or work in occupations with high exposure risk. More than 50% of farm laborers, agricultural workers, and construction workers in California are Latino.[31,32] In addition, Black and Latino persons are overrepresented in carceral facilities: in California, Black persons comprise 27% and Latino persons comprise 41% of jail and prison populations.[33]

Exposure to Particulate Matter

Persons living in environments with high concentrations of dust, which is a major constituent of particulate matter ≤10 μm or ≤2.5 μm in diameter, might be at elevated risk for infection with Coccidioides and SARS-CoV-2 and severe illness from COVID-19. Exposure to particulate matter is a risk factor for illness and death from viral respiratory infections, including COVID-19 (Appendix). Exposure to outdoor particulate air pollution is also associated with Coccidioides infection because mineral dust can mobilize airborne spores.[34,35] Coccidioidomycosis outbreaks have been linked to dust plumes generated by military exercises, agriculture, construction, archeology excavations, windstorms, and landslides.[36–43] For example, in an outbreak affecting 89 persons at a solar farm, persons who reported being in a dust cloud had ≈6 times the odds of symptomatic coccidioidomycosis than those who were not in the dust cloud. Wetting the dirt before soil-disrupting activities, a common practice to reduce dust, decreased the odds of symptomatic infection by 58%.[44] Because COVID-19 control measures encourage the use of outdoor spaces, persons might have increased exposures to mineral dust and other air pollutants during the pandemic.