Infectious disease is distinguished from most other fields of medicine by constant and rapid change. As microorganisms emerge, new treatment and prevention strategies also evolve. Although much progress has been made, infections remain a major and often preventable cause of death worldwide.In this issue of JAMA, el Bcheraoui and colleagues 1 report mortality trends for major infectious diseases in the United States, both nationally and at the county level, using data from the National Center for Health Statistics. In one of the first studies of its kind, the authors used deidentified death records to examine mortality trends for the most common causes of infectious diseases mortality, including lower respiratory infection, diarrheal disease, HIV/AIDS, hepatitis (excluding chronic hepatitis B and C), meningitis, and tuberculosis.The authors report that between 1980 and 2014, a total of 4 081 546 deaths due to infectious diseases were recorded in the United States. In 2014, a total of 113 650 (95% uncertainty interval [UI], 108 764-117 942) deaths or a rate of 34.10 (95% UI, 32.63-35.38) deaths per 100 000 persons were due to infectious diseases, compared with a total in 1980 of 72 220 (95% UI, 69 887-74 712) deaths or a rate of 41.95 (95% UI, 40.52-43.42) deaths per 100 000 persons, an overall decline of 18.73% (95% UI, 14.95%-23.33%).Lower respiratory infections remained the most common cause of infectious diseases mortality in 2014, accounting for 78.80% of all infectious diseases mortality with 26.87 (95% UI, 25.79-28.05) deaths per 100 000 persons, although mortality rates from lower respiratory infections have declined by 25.79% since 1980. It is likely that this decline is at least in part related to widespread use of pneumococcal vaccines among high-risk adults and children, yet substantial gaps in vaccine coverage persist (eg, in 2014, only 61.3% of adults 65 years and older received the recommended pneumococcal vaccines). 2 Among all of the infections evaluated by el Bcheraoui et al, 1 lower respiratory infection had the greatest variation among US counties, with some counties in the South and East demonstrating an increase in mortality due to lower respiratory infection. Although the precise reasons for these differences are not clear, socioeconomic factors contribute to risk of pneumonia. For example, persons with low income, homelessness, incarceration, and African American race/ethnicity have an increased risk of bacteremic pneumonia. 3 A recent study of Tennessee Medicaid recipients also suggested that prescription opioid use, particularly of potent, long-acting, high-dose opioids, was associated with increased risk of invasive pneumococcal disease. 4