Response rates for national population-based surveys have declined, including the National Health and Nutrition Examination Survey (NHANES). Declining response to the initial NHANES interview may impact consent and participation in downstream survey components such as record linkage, physical exams, storage of biological samples and phlebotomy. Interview response rates dropped from 68% in 2011-2012 to 53% in 2017-2018 for adults age 18 and older. Response was higher for children (1-17 years) but with a similar downward trend (2011-2012, 81%; 2017-2018, 65%). Despite declining interview response rates, changes in consent and response rates for downstream components over time have been mixed. Among those interviewed, the examination response rate was over 93%, consent for record linkage was over 90%, and consent for storage of specimens for future research was over 99%. The availability of a blood sample for storage ranged between 60%-65% for children and 78%-85% for adults.

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 (ARV) use was also included in the survey since 1999. SETTING: A continuous household-based probability sample of the U.S. population. METHODS: From 1999-2018, 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 non-significant 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% to 0.11%), women (0.22% to 0.06%) and non-Hispanic black persons (2.14% to 0.80%). Participants age aged 18-39 self-reported a decline in HIV testing while 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%. ARV therapy among those HIV positive was under 50%. CONCLUSION: Though 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 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 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.

OBJECTIVE: To examine changes in the prevalence of HIV testing among adults following CDC's 2006 revised HIV testing recommendations. DESIGN: The 2003-2010 National Health and Nutrition Examination Survey (NHANES), a nationally representative, cross-sectional survey of the non-institutionalized U.S. population. METHODS: Weighted estimates and multivariable modeling to assess prevalence of lifetime HIV testing, outside of blood donations, based on 13,975 respondents aged 18-59 years, comparing NHANES 2003-2006 and 2007-2010. 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 to 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 (STI) history, those without health insurance and those who did not access healthcare 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 STI history. CONCLUSION: 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 U.S. population has never been tested for HIV.

Prevalence of hepatitis C virus (HCV) antibody has been reported in Mexican Americans, but its prevalence in other US Hispanic/Latino groups is unknown. We studied 2 populations of US Hispanic/Latino adults; 3210 from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 and 11 964 from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Age-standardized prevalence of HCV antibody was similar in NHANES 2007-2010 (1.5%) and HCHS/SOL (2.0%) but differed significantly by Hispanic/Latino background in HCHS/SOL (eg, 11.6% in Puerto Rican men vs 0.4% in South American men). These findings suggest that the HCV epidemic among US Hispanics/Latinos is heterogeneous.

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.

Multiple myeloma (MM) incidence is markedly higher in blacks compared with whites, which may be related to a higher prevalence of monoclonal gammopathy of undetermined significance (MGUS). Our objective was to define the prevalence and risk factors of MGUS in a large cohort representative of the United States (U.S.) population. Stored serum samples from National Health and Nutritional Examination Survey (NHANES) III or NHANES 1999-2004 were available for 12 482 persons age ≥50 years (2331 'black', 2475 Hispanics, 7051 'white', and 625 'others') on which agarose-gel electrophoresis, serum protein immunofixation, serum free light-chain assay, and M-protein typing were performed. MGUS was identified in 365 participants (2.4%). Adjusted prevalence of MGUS was significantly higher (P<0.001) in blacks (3.7%) compared with whites (2.3%) (P=0.001) or Hispanics (1.8%), as were characteristics that posed a greater risk of progression to MM. The adjusted prevalence of MGUS was 3.1% and 2.1% for the North/Midwest versus South/West regions of the U.S., respectively (P=0.052). MGUS is significantly more common in blacks, and more often has features associated with higher risk of progression to MM. A strong geographic disparity in prevalence of MGUS between the North/Midwest versus the South/West regions of the U.S. was found, which has etiologic implications.

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.

BACKGROUND: Human papillomavirus (HPV) vaccination was introduced into the routine immunization schedule in the United States in late 2006 for females aged 11 or 12 years, with catch-up vaccination recommended for those aged 13-26 years. In 2010, 3-dose vaccine coverage was only 32% among 13-17 year-olds. Reduction in the prevalence of HPV types targeted by the quadrivalent vaccine (HPV-6, -11, -16, and -18) will be one of the first measures of vaccine impact. METHODS: We analyzed HPV prevalence data from the vaccine era (2007-2010) and the prevaccine era (2003-2006) that were collected during National Health and Nutrition Examination Surveys. HPV prevalence was determined by the Linear Array HPV Assay in cervicovaginal swab samples from females aged 14-59 years; 4150 provided samples in 2003-2006, and 4253 provided samples in 2007-2010. RESULTS: Among females aged 14-19 years, the vaccine-type HPV prevalence (HPV-6, -11, -16, or -18) decreased from 11.5% (95% confidence interval [CI], 9.2-14.4) in 2003-2006 to 5.1% (95% CI, 3.8-6.6) in 2007-2010, a decline of 56% (95% CI, 38-69). Among other age groups, the prevalence did not differ significantly between the 2 time periods (P > .05). The vaccine effectiveness of at least 1 dose was 82% (95% CI, 53-93). CONCLUSIONS: Within 4 years of vaccine introduction, the vaccine-type HPV prevalence decreased among females aged 14-19 years despite low vaccine uptake. The estimated vaccine effectiveness was high.

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. (HEPATOLOGY 2012;55:1652-1661).

OBJECTIVES: Depression has been linked to risky sexual behaviours in adolescents, but there is little research among adults. The goal of this analysis was to examine the associations between current depression and self-reported risky sexual behaviours in a nationally representative sample of US adults aged 20-59 years. The authors also examined the association between depression and infection with herpes simplex virus type 2 (HSV-2), a biological marker of risky sexual behaviours. METHODS: The authors used data from the 2005-2008 National Health and Nutrition Examination Surveys. Current depression was measured by the Patient Health Questionnaire-9. Antibodies to HSV-2 were tested using the enzymatic immunodot assay. The authors used logistic regression to examine the associations controlling for socio-demographic variables. RESULTS: Among 5273 adults aged 20-59 years, 7% had depression, 36% reported 10 or more lifetime sex partners, 15% had two or more past-year sex partners and 13% had first sex before 15 years of age. Persons with each of the risky sexual behaviours were more likely to have depression than those without. In stratified analyses, risky sexual behaviours were associated with depression in women but not in men. Among 3940 adults aged 20-49 years, 19% had HSV-2 infection. Persons with HSV-2 infection were more likely to have depression (OR 2.1, 95% CI 1.5 to 2.9). CONCLUSIONS: Risky sexual behaviour is related to current depression in adult women. Healthcare providers should be aware of this association and its potential implications in order to deliver better care for patients with depression or sexually transmitted infections.

Previous studies suggest that male testosterone concentrations have declined over time. To explore this in a large US population, we examined testosterone and free testosterone concentrations in National Health and Nutrition Examination Surveys (NHANES) from 1988-1991 and 1999-2004. We also examined sex hormone-binding globulin (SHBG), estradiol, and androstanediol glucuronide (3alpha-diol-G) over the same period. Non-Hispanic white, non-Hispanic black, and Mexican-American men from 1988-1991 and 1999-2004 NHANES surveys who were ≥20 years old and had serum from morning blood draws were included in this analysis (1988-1991: N = 1,413; 1999-2004: N = 902). Testosterone, estradiol and SHBG were measured by competitive electrochemiluminescence immunoassays and 3alpha-diol-G was measured by enzyme immunoassay. Free testosterone was calculated using testosterone and SHBG values. Adjusted mean hormone concentrations were estimated using linear regression, accounting for NHANES sampling weights and design, age, race/ethnicity, body mass index, waist circumference, alcohol use and smoking. Differences in adjusted mean concentrations (Delta) and two-sided p-values were calculated; p < 0.05 was statistically significant. Overall, 3alpha-diol-G and estradiol declined between 1988-1991 and 1999-2004, but there was little change in testosterone, free testosterone, or SHBG (Delta: 3alpha-diol-G = -1.83 ng/mL, p < 0.01; estradiol = -6.07 pg/mL, p < 0.01; testosterone = -0.03 ng/mL, p = 0.75; free testosterone = -0.001 ng/mL, p = 0.67; SHBG = -1.17 nmol/L, p = 0.19). Stratification by age and race revealed that SHBG and 3alpha-diol-G declined among whites 20-44 years old (Delta: SHBG = -5.14 nmol/L, p < 0.01; 3alpha-diol-G = -2.89 ng/mL, p < 0.01) and free testosterone increased among blacks 20-44 years old (Delta: 0.014 ng/mL, p = 0.03). Estradiol declined among all ages of whites and Mexican-Americans. In conclusion, there was no evidence for testosterone decline between 1988-1991 and 1999-2004 in the US general population. Subgroup analyses suggest that SHBG and 3alpha-diol-G declined in young white men, estradiol declined in white and Mexican-American men, and free testosterone increased in young black men. These changes may be related to the increasing prevalence of reproductive disorders in young men.

The 2003-2006 National Health and Nutrition Examination Surveys were used to assess human papillomavirus (HPV) types 6, 11, 16, and 18 DNA detection from females aged 14-59 years who self-collected cervicovaginal swab specimens. Prevalence was 8.8% (95% confidence interval [CI], 7.8%-10.0%) and was highest among women aged 20-24 years (18.5%; 95% CI, 14.9%-22.8%). Age group, education, marital status, and sexual behavior were associated with detection. These data provide baseline information before HPV vaccine introduction. Early impact of vaccine in the United States may be determined by a reduction in the prevalence of HPV 6, 11, 16, and 18 infection among young women.

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.

The National Health and Nutrition Examination Survey (NHANES) is a program of studies conducted since the 1960s by the National Center for Health Statistics of the U.S. Centers for Disease Control and Prevention. Its purpose is to obtain information on the health and nutritional status of the U.S. population. The survey involves interviews and physical examinations of a nationally representative sample of civilian and noninstitutionalized adults and children. From 1999-2002, and again from 2007-2008, biospecimens (blood, urine, and DNA samples) were collected from NHANES participants. In 2006, we reported on the NHANES experience with obtaining consent for the storage and use of biospecimens for data years 1999-2002. (1) In this report, we provide an update on the NHANES experience regarding consent for collecting biospecimens for data years 2007-2008 (DNA samples were not collected from 2003-2006).

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.

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.

BACKGROUND: Our objective was to assess trends in the prevalence of hepatitis B virus (HBV) infection in the United States after widespread hepatitis B vaccination. METHODS: The prevalence of HBV infection and immunity was determined in a representative sample of the US population for the periods 1999-2006 and 1988-1994. National Health and Nutrition Examination Surveys participants 6 years of age were tested for antibody to hepatitis B core antigen (anti-HBc), hepatitis B surface antigen (HBsAg), and antibody to hepatitis B surface antigen (anti-HBs). Prevalence estimates were weighted and age-adjusted. RESULTS: During the period 1999-2006, age-adjusted prevalences of anti-HBc (4.7%) and HBsAg (0.27%) were not statistically different from what they were during 1988-1994 (5.4% and 0.38%, respectively). The prevalence of anti-HBc decreased among persons 6-19 years of age (from 1.9% to 0.6%; [Formula: see text]) and 20-49 years of age (from 5.9% to 4.6%; [Formula: see text]) but not among persons 50 years of age (7.2% vs 7.7%). During 1999-2006, the prevalence of anti-HBc was higher among non-Hispanic blacks (12.2%) and persons of "Other" race (13.3%) than it was among non-Hispanic whites (2.8%) or Mexican Americans (2.9%), and it was higher among foreign-born participants (12.2%) than it was among US-born participants (3.5%). Prevalence among US-born children 6-19 years of age (0.5%) did not differ by race or ethnicity. Disparities between US-born and foreign-born children were smaller during 1999-1996 (0.5% vs 2.0%) than during 1988-1994 (1.0% vs 12.8%). Among children 6-19 years of age, 56.7% had markers of vaccine-induced immunity. CONCLUSIONS: HBV prevalence decreased among US children, which reflected the impact of global and domestic vaccination, but it changed little among adults, and approximately 730,000 US residents (95% confidence interval, 550,000-940,000) are chronically infected.

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.

We performed serum testing for IgG antibodies against Coxiella burnetii (phase I and phase II) and analyzed questionnaire data from 4,437 adults > or = 20 years of age who participated in the National Health and Nutrition Examination Survey 2003-2004 survey cycle. National Q fever seroprevalence was determined by enzyme-linked immunosorbent assay and confirmed by using immunofluorescent antibody testing. Overall seroprevalence for Coxiella burnetii was 3.1% (95% confidence interval [CI] = 2.1-4.3%) among 4,437 adults > or = 20 years of age. Coxiella burnetii age-adjusted antibody prevalence was higher for men than for women (3.8%, 95% CI = 2.7-5.2% versus 2.5%, 95% CI = 1.5-3.7%, respectively, P < 0.05). Mexican Americans had a significantly higher antibody prevalence (7.4%, 95% CI = 6.6-8.3%) than either non-Hispanic whites (2.8%, 95% CI = 1.7-4.3%) or non-Hispanic blacks (1.3%, 95% CI = 0.6-2.5%) (P < 0.001). Multivariate analysis showed that the risk for Q fever antibody positivity increased with age and was higher among persons who were foreign-born, male, and living in poverty. These findings indicate that the national seroprevalence of Q fever in the United States is higher than expected on the basis of case numbers reported to the Centers for Disease Control and Prevention from state health departments. Potential differences in risk for exposure by race/ethnicity warrant further study.

BACKGROUND: Human papillomavirus (HPV) seroprevalence data can help define the epidemiology of this common sexually transmitted pathogen. METHODS: We determined the seroprevalence of HPV types 6, 11, 16, and 18 (HPV types in the quadrivalent vaccine) among 4303 persons aged 14-59 years who participated in the National Health and Nutrition Examination Survey 2003-2004. RESULTS: The seroprevalences of HPV types 6, 11, 16, and 18 among female subjects were 17.0%, 7.1%, 15.6%, and 6.5%, respectively. Among males, the seroprevalences were lower for each type, with 6.3% observed for HPV-6, 2.0% for HPV-11, 5.1% for HPV-16, and 1.5% for HPV-18 ([Formula: see text] for all comparisons). For any HPV vaccine type, the seroprevalence was 32.5% among females and 12.2% among males; the seroprevalence of any HPV vaccine type increased with age, reaching 42.0% among women aged 30-39 years and 18.0% among men aged 50-59 years. Antibodies to all 4 vaccine types were detected in 0.4% of females and 0% of males. Non-Hispanic blacks had a higher seroprevalence of any HPV vaccine type than that observed for non-Hispanic whites or Mexican Americans. Age and lifetime number of sex partners were factors independently associated with seroprevalence of any HPV vaccine type among both females and males, and poverty level was also a factor among females. CONCLUSIONS: This is the first population-based seroprevalence study in the United States of all 4 HPV types targeted by the quadrivalent vaccine, and its findings can inform vaccine policy.

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 18-49 years were tested for HIV antibody. Prevalence estimates were weighted to account for oversampling and nonresponse. RESULTS: There were 67 HIV antibody-reactive individuals for a seroprevalence of 0.5% [95% confidence interval (CI) 0.3-0.6]. In the only age subgroup directly comparable between surveys (18-39 years), HIV seroprevalence remained constant from NHANES III (1988-1994) to NHANES 1999-2002 and 2003-2006. In NHANES 1999-2006, non-Hispanic blacks had significantly higher HIV seroprevalence (2.0%, 95% CI 1.5-2.7) 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 5.0-17.1), among persons who had detectable antibody to herpes simplex type-two (1.9% 95% CI 1.4-2.8), among those who had 50 or more lifetime sex partners (3.4%, 95% CI 1.7-6.7), and among those who never married (0.8%, 95% CI 0.5-1.3). CONCLUSIONS: In this household-based population, seroprevalence did not significantly change from NHANES III to NHANES 1999-2006. Non-Hispanic 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.