Background Studying HIV transmission networks provides insight into the spread of HIV and opportunities for intervention. We identified transmission dynamics among risk groups and racial/ethnic groups in the United States. Methods For HIV-1 pol sequences reported to the U.S. National HIV Surveillance System during 2001–2012, we calculated pairwise genetic distance, identified linked pairs of sequences (those with distance ≤1.5%), and examined transmission category and race/ethnicity of these potential transmission partners. Results Of 40,950 sequences, 12,910 (32%) linked to ≥1 other sequence. Of men who have sex with men (MSM) who linked to ≥1 sequence, 88% were linked to other MSM and only 4% were linked to heterosexual women. Of heterosexual women for whom we identified potential transmission partners, 29% linked to MSM, 21% to heterosexual men, and 12% to persons who inject drugs. Older and black MSM were more likely to be linked to heterosexual women. Assortative mixing was present for all racial/ethnic groups; 81% of blacks/African Americans linked to other blacks. Conclusions This analysis is the first use of U.S. surveillance data to infer an HIV transmission network. Our data suggest that HIV infections among heterosexual women predominantly originate from MSM, followed by heterosexual men. Although few MSM were linked to women, suggesting that a minority of MSM are involved in transmission with heterosexual women, these transmissions represent a substantial proportion of HIV acquisitions by heterosexual women. Interventions that reduce transmissions involving MSM are likely to also reduce HIV acquisition among other risk groups.

Hispanics or Latinos represent about 17% of the total U.S. population and are disproportionately affected by human immunodeficiency virus (HIV) infection in the United States. In 2013, the rate of HIV diagnosis among Hispanics or Latinos (18.7) was nearly three times that of non-Hispanic whites (6.6). To better characterize HIV infection among Hispanics or Latinos aged ≥13 years in the United States, CDC analyzed data from the National HIV Surveillance System (NHSS). During 2008-2013, the rate of diagnoses of HIV infection among adult and adolescent Hispanics or Latinos decreased from 28.3 per 100,000 population in 2008 to 24.3 in 2013 (estimated annual percentage change [EAPC] = -3.6); however, the number of diagnoses among males with infection attributed to male-to-male sexual contact increased 16%, from 6,141 in 2008 to 7,098 in 2013 (EAPC = 3.0). In 2013, the rate of diagnosis of HIV infection among males (41.3) was six times the rate among females (6.8). During 2008-2013, behavioral risk factors for HIV infection among Hispanics or Latino differed among males and females and by place of birth. Among Hispanic or Latino males born in Puerto Rico, the proportion of HIV infections attributed to injection drug use (24.9%) was greater than among those born elsewhere. Among HIV-infected Hispanic or Latino females, those born in the United States (21.2%) and Puerto Rico (20.5%) had a greater proportion of HIV infections attributed to injection drug use than those born elsewhere. Additional interventions and public health strategies to further decrease the rates of HIV among the Hispanic or Latino population are needed.

The public health consequences of hazardous substance releases have not been characterized adequately. In response, therefore, the Agency for Toxic Substances and Disease Registry implemented an active, state-based surveillance system. Information is collected with respect to the events, chemicals, victims, injuries, and evacuations. Five states reported 1,249 events during 1990 and 1991. Seventy-two percent of the events occurred at fixed facilities, and 28% of the events were transportation related. In 80% of the events, one chemical was released. The most frequently released chemicals were herbicides, acids, volatile organic compounds, and ammonias. In 204 events, 846 persons were injured and 7 died. Employees were injured more frequently than first responders or the general public. The most frequently reported injuries were respiratory irritation and eye irritation. Evacuations occurred in 14% of the events. These results provide information for preparedness planning and training of first responders and employees.

Lack of health insurance coverage is associated with lack of accessibility to preventive health care services such as mammography screening, clinical breast examination, Papanicolaou smear test, digital rectal examination, proctoscopy examination, and cholesterol screening. State and federal public health agencies must have an understanding of insurance coverage of the population to plan intervention programs aimed at early detection of medical conditions. Using data from the March Supplement of the Current Population Survey for the years 1994, 1995, and 1996, this study examines the sources of health insurance coverage in the U.S. The implications of the findings for public health programs are discussed.

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