Prevalence and Trends in HIV Infection and Testing Among Adults in the United States: The National Health and Nutrition Examination Surveys, 1999-2018.

BACKGROUND: HIV antibody testing has been included in the National Health and Nutrition Examination Survey, for ages 18-49 since 1999 and for ages 18-59 years since 2009 enabling estimation of trends in HIV prevalence as part of national surveillance in the U.S. household population. Self-reported HIV testing and antiretroviral use was also included in the survey since 1999. SETTING: A continuous household-based probability sample of the U.S. population. METHODS: From 1999 to 2018, 29,020 participants age 18-49 years were tested for HIV antibody and 34,092 participants age 18-59 years were asked about self-report of any previous HIV testing. RESULTS: HIV prevalence was 0.41% among those aged 18-59 in 2009-2018 with a nonsignificant trend over time among those aged 18-49 years from 1999-2002 to 2015-2018. However, significant declines in prevalence were seen among those aged 18-39 years (0.37%-0.11%), women (0.22%-0.06%) and non-Hispanic black persons (2.14%-0.80%). Participants aged 18-39 years self-reported a decline in HIV testing, whereas those aged 40-49 and 50-59 years, non-Hispanic black persons and women reported an increase in getting a HIV test. Prevalence of infection and self-reported history of HIV testing varied by demographic and risk groups. HIV testing among HIV-positive persons was 83.9%. Antiretroviral therapy among those HIV-positive was under 50%. CONCLUSION: Although total HIV prevalence and previous self-reported HIV testing remained stable for the last 20 years, there were significant declines in age and demographic subgroups. Prevalence for both outcomes varied by demographic and risk variables.

Toxoplasma gondii Infection in the United States, 2011-2014.

Toxoplasma gondii can cause severe neurologic and ocular disease when transmitted congenitally and in immunosuppressed persons. Sera collected in the National Health and Nutrition Examination Survey 2011 through 2014 in 13,507 persons ≥ 6 years old were tested for T. gondii immunoglobulin (Ig) G and IgM antibodies, and in those both IgG and IgM antibody positive, for IgG avidity. Overall, 11.14% (95% confidence limits [CL] 9.88%, 12.51%) were seropositive for T. gondii IgG antibody (age-adjusted seroprevalence 10.42% [95% CL 9.19%, 11.76%]); in women aged 15-44 years, the age-adjusted T. gondii IgG seroprevalence was 7.50% (95% CL 6.00%, 9.25%). In multivariable analysis, risk for IgG seropositivity increased with age and was higher in males; persons living below the poverty level; persons with ≤ a high school education compared with those with > a high school education; and non-Hispanic black, Mexican American, and foreign born non-Hispanic white persons compared with U.S.-born non-Hispanic white persons. Overall, 1.16% (95% CL 0.94%, 1.42%) were T. gondii IgM antibody positive and 0.71%, (95% CL 0.54%, 0.92%) were both IgM and IgG antibody positive. In multivariable analysis, the significant risk factors for being both IgM and IgG positive were older age, crowding, and non-U.S. birth origin compared with U.S.-born persons. Among those positive for both IgM and IgG antibody, almost all had high avidity (all women aged 15-44 years had high avidity). Toxoplasma gondii antibody prevalence remains relatively low in the United States, although it is higher in non-U.S.-born persons, males, and some minority and socioeconomically disadvantaged groups.

National Health and Nutrition Examination Survey Biospecimen Program: NHANES III (1988-1994) and NHANES 1999-2014.

BACKGROUND: The National Health and Nutrition Examination Survey's 9NHANES) biospecimena program was formed to manage the collection of biospecimena (including serum, plasma, urine, and DNA) from NHANES cycles, the storage of biospecimens in NHANES biospecimens, accessing of biospecimens by researchers and the providing of resulting data to future researchers. Data from biospeceimen research can be combined with existing NHANES data. OBJECTIVE: This report provides background on the development of NHANES biorepositories and describes the collection, processing, and storing of biospecimens; ethical considerations and informed consent; and the proposal process for accessing biospecimens and resulting data. The number and types of biospecimens collected in each survey cycle from NHANES III (1988- 1994) through NHANES 1999-2014 are discussed so that researchers can understand what biospecimens are available if they are considering using NHANES biospecimens in their research.

Did CDC's 2006 revised HIV testing recommendations make a difference? Evaluation of HIV testing in the US household population, 2003-2010.

OBJECTIVE: To examine changes in the prevalence of HIV testing among adults following the Centers for Disease Control and Prevention's 2006 revised HIV testing recommendations. DESIGN: The 2003-2010 National Health and Nutrition Examination Survey, a nationally representative cross-sectional survey of the noninstitutionalized US population. METHODS: Weighted estimates and multivariable modeling to assess the prevalence of lifetime HIV testing, outside of blood donations, based on 13,975 respondents aged 18-59 years, comparing the 2003-2006 and 2007-2010 National Health and Nutrition Examination Survey. RESULTS: Overall, HIV testing was 42.1% during 2003-2006 and 44.5% during 2007-2010 (P > 0.05). After adjusting for significant predictors in a multivariate model, HIV testing increased from 2003-2006 to 2007-2010 (adjusted odds ratio [aOR] 1.14, P < 0.05), mostly among males (aOR 1.33, P < 0.001) as compared with females (aOR 1.02, P > 0.05). HIV testing also increased significantly among non-Hispanic blacks, heterosexuals, those aged 50-59 years, those without a sexually transmitted infection history, those without health insurance, and those who did not access health care in the past year. HIV testing did not change significantly among high-risk groups, including men who have sex with men, those with a history of injection or illicit drug use, and those with a sexually transmitted infection history. CONCLUSIONS: In multivariate modeling, we found a modest but significant increase in HIV testing overall and among males after publication of the revised recommendations for HIV testing. The significant increase in non-high-risk groups suggests an expansion in generalized HIV testing, as recommended. However, even in 2007-2010, 56% of the US population has never been tested for HIV.

Chronic hepatitis C virus infection in the United States, National Health and Nutrition Examination Survey 2003 to 2010.

BACKGROUND: Knowledge of the number of persons with chronic hepatitis C virus (HCV) infection in the United States is critical for public health and policy planning. OBJECTIVE: To estimate the prevalence of chronic HCV infection between 2003 and 2010 and to identify factors associated with this condition. DESIGN: Nationally representative household survey. SETTING: U.S. noninstitutionalized civilian population. PARTICIPANTS: 30,074 NHANES (National Health and Nutrition Examination Survey) participants between 2003 and 2010. MEASUREMENTS: Interviews to ascertain demographic characteristics and possible risks and exposures for HCV infection. Serum samples from participants aged 6 years or older were tested for antibody to HCV; if results were positive or indeterminate, the samples were tested for HCV RNA, which indicates current chronic infection. RESULTS: Based on 273 participants who tested positive for HCV RNA, the estimated prevalence of HCV infection was 1.0% (95% CI, 0.8% to 1.2%), corresponding to 2.7 million chronically infected persons (CI, 2.2 to 3.2 million persons) in the U.S. noninstitutionalized civilian population. Infected persons were more likely to be aged 40 to 59 years, male, and non-Hispanic black and to have less education and lower family income. Factors significantly associated with chronic HCV infection were illicit drug use (including injection drugs) and receipt of a blood transfusion before 1992; 49% of persons with HCV infection did not report either risk factor. LIMITATION: Incarcerated and homeless persons were not surveyed. CONCLUSION: This analysis estimated that approximately 2.7 million U.S. residents in the population sampled by NHANES have chronic HCV infection, about 500,000 fewer than estimated in a similar analysis between 1999 and 2002. These data underscore the urgency of identifying the millions of persons who remain infected and linking them to appropriate care and treatment. PRIMARY FUNDING SOURCE: None.

Seroprevalence of herpes simplex virus types 1 and 2--United States, 1999-2010.

BACKGROUND: Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are common infections with serious sequelae. HSV-1 is an increasingly important cause of genital herpes in industrialized countries. METHODS: Using nationally representative data from the National Health and Nutrition Examination Survey (NHANES), we examined HSV-1 and HSV-2 seroprevalence among 14- to 49-year-olds in the United States. We estimated seroprevalence in 1999-2004 and 2005-2010, stratified by sociodemographic characteristics and sexual behaviors. We also reviewed HSV-1 and HSV-2 seroprevalence from 1976-1980 to 2005-2010. RESULTS: In 2005-2010, the seroprevalence of HSV-1 was 53.9%, and the seroprevalence of HSV-2 was 15.7%. From 1999-2004 to 2005-2010, HSV-1 seroprevalence declined by nearly 7% (P < .01), but HSV-2 seroprevalence did not change significantly. The largest decline in HSV-1 seroprevalence from 1999-2004 to 2005-2010 was observed among adolescents aged 14-19 years, among whom seroprevalence declined by nearly 23%, from 39.0% to 30.1% (P < .01). In this age group, HSV-1 seroprevalence declined >29% from 1976-1980 to 2005-2010 (P < .01). CONCLUSIONS: An increasing number of adolescents lack HSV-1 antibodies at sexual debut. In the absence of declines in HSV-2 infections, the prevalence of genital herpes may increase.

Change in Hepatitis A Seroprevalence among U.S. Children and Adolescents: Results from the National Health and Nutrition Examination Survey 2003-2006 and 2007-2010.

To examine changes in seroprevalence of antibodies to hepatitis A virus (HAV) during a period in which universal vaccine recommendations for all U.S. children were implemented, results from serologic testing from the National Health and Nutrition Examination Survey (NHANES) from 2003-2010 were analyzed among 7,989 participants age 6-19 years, born in the U.S. in two birth cohorts (1986-1996 and 1997-2004). Overall prevalence increased over time from 24.4% in 2003-2006 to the highest ever reported (37.6%) in 2007-2010. Specifically, increases reached statistical significance in the birth cohort born in the years after implementation of vaccine recommendations (1997-2004), among those of race/ethnicity other than white, non-Hispanic, and among states where recommendations were implemented later. The greatest increase over time was among the subgroup of persons in states with early implementation who were of race/ethnicity other than white, non-Hispanic. Geographic region and birth cohort based on vaccine recommendations as well as race/ethnicity were the main predictors of seropositivity in 2007-2010. The increase in Hepatitis A seroprevalence occurred during a time of decreasing incidence and increasing vaccination, however race/ethnic disparities persist.

Relationship of sex steroid hormones with body size and with body composition measured by dual-energy X-ray absorptiometry in US men.

PURPOSE: To evaluate the association of body size-captured via whole-body dual-energy X-ray absorptiometry (DXA) and physical measurement-with serum sex steroid hormones and sex hormone binding globulin (SHBG), we utilized cross-sectional data and serum samples from the National Health and Nutrition Examination Survey (NHANES; 1999-2004). METHODS: Testosterone, androstanediol glucuronide (3-alpha-diol-G), estradiol, and SHBG were measured via immunoassay in serum samples from a total of 898 adult men (ages 20-90) participating in the morning examination. As part of the NHANES data collection, DXA scans and measurements of weight, height, and waist circumference were performed by trained staff. Linear regression was used to estimate associations between body size and hormone levels adjusted for potential confounders and NHANES sampling procedures. RESULTS: Total bone area (cm(2)) was inversely associated with total testosterone (ng/mL) [beta = -0.12; p value < 0.01], while bone mineral density (g/cm(2)) was inversely associated with SHBG (nmol/L) [beta = -17.16; p value = 0.01]. Increased percent body fat was associated with lower concentrations of total testosterone [beta = -0.16; p value < 0.01] and SHBG [beta = -1.11; p value < 0.01] and higher concentrations of free estradiol (fg/mL) [beta = 12.52; p value < 0.01]. CONCLUSIONS: Clinical measures of body fat (measured via DXA scan) and anthropometric measures of body fat (BMI and waist circumference) provided similar inferences regarding the association between increased body fat and hormone levels in men. Increased body fat was associated with lower circulating levels of testosterone (total and free) and SHBG and higher circulating levels of free estradiol in men, while decreased bone mineral density was associated with higher circulating levels of SHBG.

Awareness of infection, knowledge of hepatitis C, and medical follow-up among individuals testing positive for hepatitis C: National Health and Nutrition Examination Survey 2001-2008.

UNLABELLED: Many persons infected with hepatitis C virus (HCV) are unknown to the healthcare system because they may be asymptomatic for years, have not been tested for HCV infection, and only seek medical care when they develop liver-related complications. We analyzed data from persons who tested positive for past or current HCV infection during participation in the National Health and Nutrition Examination Survey (NHANES) from 2001 through 2008. A follow-up survey was conducted 6 months after examination to determine (1) how many participants testing positive for HCV infection were aware of their HCV status before being notified by NHANES, (2) what actions participants took after becoming aware of their first positive test, and (3) participants' knowledge about hepatitis C. Of 30,140 participants tested, 393 (1.3%) had evidence of past or current HCV infection and 170 (43%) could be contacted during the follow-up survey and interviewed. Only 49.7% were aware of their positive HCV infection status before being notified by NHANES, and only 3.7% of these respondents reported that they had first been tested for HCV because they or their doctor thought they were at risk for infection. Overall, 85.4% had heard of hepatitis C; correct responses to questions about hepatitis C were higher among persons 40-59 years of age, white non-Hispanics, and respondents who saw a physician after their first positive HCV test. Eighty percent of respondents indicated they had seen a doctor about their first positive HCV test result. CONCLUSION: These data indicate that fewer than half of those infected with HCV may be aware of their infection. The findings suggest that more intensive efforts are needed to identify and test persons at risk for HCV infection.

Seroprevalence of hepatitis A virus antibodies in the U.S.: results from the National Health and Nutrition Examination Survey.

OBJECTIVES: We described seroprevalence of antibody to hepatitis A virus (anti-HAV) in the United States during 1999-2006 and compared it with seroprevalence before the availability of vaccine. METHODS: We analyzed data from the 1988-1994 and 1999-2006 National Health and Nutrition Examination Survey (NHANES) to obtain estimates of anti-HAV seroprevalence for the U.S. household population. We grouped region of residence based on the 1999 Advisory Committee on Immunization Practices recommendations into 17 states with any recommendation (vaccinating) and 33 states without any recommendation (non-vaccinating). RESULTS: During 1999-2006, the overall seroprevalence of anti-HAV was 34.9% (95% confidence interval [CI] 33.1, 36.7). During 1999-2006, U.S.-born children living in vaccinating states (33.8%, 95% CI 26.2, 42.2) had a higher seroprevalence than children in non-vaccinating states (11.0%, 95% CI 9.4, 12.8; p < 0.001). Seroprevalence among children increased from 8.0% (95% CI 6.3, 10.1) during 1988-1994 to 20.2% (95% CI 16.0, 24.8) during 1999-2006 (p < 0.001). For U.S.-born children aged 6-19 years, the strongest factor associated with seroprevalence was residence in vaccinating states. Among U.S.-born adults aged > 19 years, the overall age-adjusted seroprevalence of anti-HAV was 29.9% (95% CI 28.3, 31.5) during 1999-2006, which was not significantly different from the seroprevalence during 1988-1994 (32.2%, 95% CI 30.1, 34.4). CONCLUSIONS: Increases in seroprevalence among children in vaccinating states suggest a positive effect of the 1999 vaccination recommendations.

Varicella seroprevalence in the U.S.: data from the National Health and Nutrition Examination Survey, 1999-2004.

OBJECTIVE: We estimated the varicella seroprevalence among the U.S. population aged 6-49 years based on retested National Health and Nutrition Examination Survey (NHANES) specimens collected between 1999 and 2004--originally tested using a method unsuitable for detecting vaccine-induced immunity--and compared it with historical estimates. METHODS: We performed a confirmatory test suitable for detecting vaccine-induced immunity on all available specimens from 6- to 19-year-olds who originally tested negative (n = 633), and on 297 randomly selected specimens that had tested positive. Retest results superseded original results for determining seroprevalence. We assessed seroprevalence for the entire sample aged 6-49 years (n = 16,050) by participant demographic characteristics and compared it with historical estimates (NHANES 1988-1994). RESULTS: The percentage of false-negative results for the original test was higher for specimens from younger children (6-11 years of age: 27.5%; 12-19 years of age: 13.3%) and for specimens collected most recently (2001-2004: 26.0%; 1999-2000: 12.6%). The age-adjusted rate of varicella seroprevalence for 1999-2004 was 93.6% for 6- to 19-year-olds and 98.0% for adults aged 20-49 years compared with 90.0% and 98.1%, respectively, for 1988-1994. We found an increase in seropositivity between the survey periods, from 93.2% to 97.2% (p < 0.001) among 12- to 19-year-olds. For children, non-Hispanic black ethnicity and younger age were associated with lower seroprevalence in both survey periods. CONCLUSIONS: Varicella seroprevalence increased with age among children and was uniformly high in the U.S. adult population between 1999 and 2004. The original testing produced false-negative seroprevalence results among children's specimens collected between 1999 and 2004 from 6- to 19-year-olds.

Seroprevalence of antibody to mumps virus in the US population, 1999-2004.

BACKGROUND: In 2006, the largest mumps outbreak in the United States in 20 years occurred. To understand prior mumps seroprevalence and factors associated with the presence of antibody to mumps virus, data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES) were analyzed. METHODS: A mumps virus-specific enzyme immunoassay was used to measure the seroprevalence of serum immunoglobulin G (IgG) antibody among NHANES participants aged 6-49 years. Participants were grouped on the basis of 10-year birth cohorts, 95% confidence intervals (CIs) were calculated using SUDAAN software, and logistic regression was used to identify independent predictors. RESULTS: The overall age-adjusted seroprevalence of IgG antibody to mumps virus during 1999-2004 was 90.0% (95% CI, 88.8%-91.1%). Seroprevalence was higher among US-born non-Hispanic blacks (96.4% [95% CI, 95.5%-97.2%]) and non-US-born Mexican Americans (93.7% [95% CI, 92.0%-95.2%]). Seroprevalence was significantly lower in the 1967-1976 birth cohort (85.7% [95% CI, 83.5%-87.8%]). The variables sex, education, and race/ethnicity/birthplace were independent predictors in at least 1 of the birth cohorts. CONCLUSIONS: The overall estimate of 90.0% is at the lower end of the estimated population immunity (90%-92%) needed to achieve herd immunity. Lower seroprevalence among groups suggest that they represent populations at an increased risk. For mumps control, high vaccine coverage and high population immunity must be achieved and maintained.

Seroprevalence of HIV in the US Household Population Aged 18­49 Years: The National Health and Nutrition Examination Surveys, 1999­2006.

OBJECTIVE: To monitor trends in HIV seroprevalence in the United States, HIV testing was included in the National Health and Nutrition Examination Survey (NHANES) conducted from 1999 to 2006. METHODS: From 1999 to 2006, 11,928 participants aged 18­49 years were tested for HIV antibody. Prevalence estimates were weighted to account for over sampling and nonresponse. RESULTS: There were 67 HIV antibody-reactive individuals for a seroprevalence of 0.5% [95% confidence interval (CI) 0.3­0.6]. In the only age subgroup directly comparable between surveys (18­39 years), HIV seroprevalence remained constant from NHANES III(1988­1994) to NHANES 1999­2002 and 2003­2006. In NHANES 1999­2006, non­Hispanic blacks had significantly higher HIV seroprevalence(2.0%, 95% CI 1.5­2.7) compared with individuals in all other race/ethnic groups combined. Seroprevalence was also higher in each race/ethnic group among men who have sex with men (9.4%95% CI 5.0­17.1), among persons who had detectable antibody to herpes simplex type-two (1.9% 95% CI 1.4­2.8), among those who had 50 or more lifetime sex partners (3.4%, 95% CI 1.7­6.7), and among those who never married (0.8%, 95% CI 0.5­1.3). CONCLUSIONS: In this household-based population, seroprevalence did not significantly change from NHANES III to NHANES 1999­2006. Non­Hispanic blacks had significantly higher prevalence of infection compared with other race/ethnic groups. Male-to-male sex and the presence of HSV-2 antibody were the strongest predictors of HIV infection

Prevalence of sexually transmitted infections among female adolescents aged 14 to 19 in the United States.

OBJECTIVE: Most young women initiate sexual activity during adolescence; risk for sexually transmitted infections (STIs) accompanies this initiation. In this study we estimated the prevalence of the most common STIs among a representative sample of female adolescents in the United States. METHODS: Data were analyzed from 838 females who were aged 14 to 19 and participating in the nationally representative National Health and Nutrition Examination Survey 2003-2004. After interview and examination, survey participants provided biological specimens for laboratory testing. The main outcome was weighted prevalence of at least 1 of 5 STIs: Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, herpes simplex virus type 2, and human papillomavirus (HPV) (any of 23 high-risk types or type 6 or 11). RESULTS: Prevalence of any of the 5 STIs was 24.1% among all and 37.7% among sexually experienced female adolescents. HPV (23 high-risk types or type 6 or 11) was the most common STI among all female adolescents (prevalence: 18.3%), followed by C trachomatis infection (prevalence: 3.9%). Prevalence of any of the STIs was 25.6% among those whose age was the same or 1 year greater than their age at sexual initiation and 19.7% among those who reported only 1 lifetime sex partner. CONCLUSIONS: The prevalence of STIs among female adolescents is substantial, and STIs begin to be acquired soon after sexual initiation and with few sex partners. These findings support early and comprehensive sex education, routine HPV vaccination at the age of 11 to 12 years, and C trachomatis screening of sexually active female adolescents.

Epidemiology of hepatitis E virus in the United States: results from the Third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: Hepatitis E virus (HEV) is prevalent and causes disease worldwide, but its epidemiological profile is only partially understood. METHODS: We used an enzyme immunoassay to measure anti-HEV immunoglobulin G antibodies in 18,695 serum samples collected in the Third National Health and Nutrition Examination Survey. We calculated estimates of HEV seroprevalence and examined associations with putative risk factors. RESULTS: The seroprevalence of HEV in the civilian noninstitutionalized United States (US) population during the period from 1988 through 1994 was 21.0% (95% confidence interval [CI], 19.0%-22.9%). Among US-born individuals, males, non-Hispanic whites, and individuals residing in the Midwest and/or in metropolitan areas had the highest seroprevalence estimates. Having a pet in the home (odds ratio [OR], 1.19 [95% CI, 1.01-1.40]) and consuming liver or other organ meats more than once per month (OR, 1.38 [95% CI, 1.01-1.88]) were significantly associated with increased odds of HEV seropositivity. CONCLUSIONS: Exposure to HEV is common in the US population, although hepatitis E is rarely reported. Having pets and consuming organ meats may play a role in HEV transmission in the United States, but other mechanisms of transmission may also exist. HEV may be considered a possible etiologic agent of acute and chronic hepatitis in US patients reporting no travel history.

Prevalence of syphilis seroreactivity in the United States: data from the National Health and Nutrition Examination Surveys (NHANES) 2001-2004.

BACKGROUND: There have been no recent US population-based estimates of syphilis seroprevalence. We determined the prevalence of syphilis seroreactivity among a representative sample of the US population. METHODS: Sera from 18- to 49-year-old participants in the National Health and Nutrition Examination Surveys 2001-2004 were tested for syphilis IgG antibody using an enzyme immunoassay (EIA). Specimens with positive or indeterminate EIAs underwent rapid plasma reagin (RPR) testing; RPR titers > or =1:8 were considered positive. Specimens with RPR titers <1:8 underwent confirmatory testing with Treponema pallidum particle agglutination (TP-PA). RESULTS: Sera were available for 5767 participants. EIA testing was positive or indeterminate for 126, of which 10 had RPR titers > or =1:8. Of the remaining 116 specimens, 60 had positive TP-PA tests, including all 19 with RPR titers >1:1. Overall weighted syphilis seroprevalence was 0.71% (95% CI: 0.51-0.96). Prevalence was similar among males (0.76%) and females (0.67%) and increased with age, less education, and lower income (P <0.001 for each). Non-Hispanic blacks had the highest prevalence (4.3%), followed by Mexican-Americans (0.98%) and non-Hispanic whites (0.07%; P <0.001). CONCLUSIONS: The prevalence of syphilis seroreactivity was low (0.71%) in the general US population of 18- to 49-year-olds. However, consistent with surveillance data, this nationally representative survey showed substantial disparities in syphilis by race/ethnicity.

HIV infection in the United States household population aged 18-49 years: results from 1999-2006.

Data from the National Health and Nutrition Examination Surveys (NHANES). The prevalence of HIV infection among adults aged 18-49 years residing in households in the United States was 0.47% for the period 1999-2006. Men were more likely to be HIV positive than women. Race/ethnic disparities in HIV infection were also seen. Non-Hispanic blacks were more likely to be HIV positive than all other race/ethnic groups. Infection with HSV-2 was significantly associated with HIV infection among the total population aged 18-49 years and especially so among the non-His-panic black population. In 1999-2006, nearly one-quarter of HIV-positive individuals but only 1% of the HIV-negative individuals aged 18-49 years had low CD4 counts (a marker of decreased immune function). Approximately one-third of HIV-positive persons had healthy immune systems as compared with 90% among those HIV negative.

Prevalence of tuberculosis infection in the United States population: the national health and nutrition examination survey, 1999-2000.

RATIONALE: The goal for tuberculosis (TB) elimination in the United States is a TB disease incidence of less than 1 per million U.S. population by 2010, which requires that the latent TB infection (LTBI) prevalence be less than 1% and decreasing. OBJECTIVES: To estimate the prevalence of LTBI in the U.S. population. METHODS AND MEASUREMENTS: Interviews and medical examinations, including tuberculin skin testing (TST), of 7,386 individuals were conducted in 1999-2000 as part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the civilian, noninstitutionalized U.S. population. LTBI was defined as a TST measurement of >/=10 mm. Associations of age, race/ethnicity, sex, poverty, and birthplace were assessed. Results among the 24- to 74-year-old subgroup were compared with NHANES 1971-1972 data. MEASUREMENTS AND MAIN RESULTS: Estimated LTBI prevalence was 4.2%; an estimated 11,213,000 individuals had LTBI. Among 25- to 74-year-olds, prevalence decreased from 14.3% in 1971-1972 to 5.7% in 1999-2000. Higher prevalences were seen in the foreign born (18.7%), non-Hispanic blacks/African Americans (7.0%), Mexican Americans (9.4%), and individuals living in poverty (6.1%). A total of 63% of LTBI was among the foreign born. Among the U.S. born, after adjusting for confounding factors, LTBI was associated with non-Hispanic African-American race/ethnicity, Mexican American ethnicity, and poverty. A total of 25.5% of persons with LTBI had been previously diagnosed as having LTBI or TB, and only 13.2% had been prescribed treatment. CONCLUSIONS: In addition to basic TB control measures, elimination strategies should include targeted evaluation and treatment of individuals in high-prevalence groups, as well as enhanced support for global TB prevention and control.

Seroprevalence of measles antibody in the US population, 1999-2004.

BACKGROUND: Endemic measles transmission was declared eliminated in the United States in 2000. To ensure that elimination can be maintained, high population immunity must be sustained and monitored. Testing for measles antibody was included in the National Health and Nutrition Examination Survey (NHANES), a nationally representative survey, conducted during 1999-2004. METHODS: A measles-specific immunoassay was used to measure the seroprevalence of measles antibody in NHANES participants 6-49 years of age. For analysis, participants were grouped by birth cohort. RESULTS: During 1999-2004, the rate of measles seropositivity in the population overall was 95.9% (95% confidence interval [CI], 95.1%-96.5%). The highest seroprevalence of measles antibody was in non-Hispanic blacks (98.6% [95% CI, 98.0%-99.1%]). Those born during 1967-1976 had significantly lower levels of measles antibody (92.4% [95% CI, 90.8%-93.9%]) than did the other birth cohorts. Independent predictors of measles seropositivity in the 1967-1976 birth cohort were non-Hispanic/black race/ethnicity, more than a high school education, having health insurance, and birth outside the United States. CONCLUSIONS: Measles seropositivity was uniformly high in the US population during 1999-2004. Nearly all population subgroups had evidence of measles seropositivity levels greater than the estimated threshold necessary to sustain measles elimination. Non-Hispanic whites and Mexican Americans born during 1967-1976 had the lowest measles seropositivity levels and represent populations that might be at increased risk for measles disease if the virus were reintroduced into the United States.