1
|
Waters MB, Hybiske K, Ikeda R, Kaltenboeck B, Manhart LE, Kreisel KM, Khosropour CM. Chlamydia trachomatis Seroassays Used in Epidemiologic Research: A Narrative Review and Practical Considerations. J Infect Dis 2024; 230:250-262. [PMID: 39052727 PMCID: PMC11272089 DOI: 10.1093/infdis/jiae199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/20/2024] [Accepted: 04/16/2024] [Indexed: 04/21/2024] Open
Abstract
Chlamydia trachomatis (CT) is a sexually transmitted infection that can lead to adverse reproductive health outcomes. CT prevalence estimates are primarily derived from screening using nucleic acid amplification tests (NAATs). However, screening guidelines in the United States only include particular subpopulations, and NAATs only detect current infections. In contrast, seroassays identify past CT infections, which is important for understanding the public health impacts of CT, including pelvic inflammatory disease and tubal factor infertility. Older seroassays have been plagued by low sensitivity and specificity and have not been validated using a consistent reference measure, making it challenging to compare studies, define the epidemiology of CT, and determine the effectiveness of control programs. Newer seroassays have better performance characteristics. This narrative review summarizes the "state of the science" for CT seroassays that have been applied in epidemiologic studies and provides practical considerations for interpreting the literature and employing seroassays in future research.
Collapse
Affiliation(s)
| | - Kevin Hybiske
- Department of Medicine, University of Washington, Seattle
| | - Ren Ikeda
- Department of Medicine, University of Washington, Seattle
| | - Bernhard Kaltenboeck
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | | | - Kristen M Kreisel
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | |
Collapse
|
2
|
Pang Y, Shui J, Li C, Li Y, Chen H, Tang S. The serodiagnositic value of Chlamydia trachomatis antigens in antibody detection using luciferase immunosorbent assay. Front Public Health 2024; 12:1333559. [PMID: 38476494 PMCID: PMC10927828 DOI: 10.3389/fpubh.2024.1333559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 02/14/2024] [Indexed: 03/14/2024] Open
Abstract
Introduction Among the different antigens used in the detection of anti-Chlamydia trachomatis antibodies, significant differences in sensitivity and specificity have been observed. Further evaluation of C. trachomatis antigens in antibody detection is urgently needed for the development and application of C. trachomatis serologic assays. Methods Chlamydia trachomatis antigens Pgp3, TmeA, InaC, and HSP60 were selected and used in luciferase immunosorbent assay (LISA). The detection results obtained from well-defined C. trachomatis positive and negative samples were compared with the commercial C. trachomatis ELISA (Mikrogen) for performance evaluation. Results Pgp3, TmeA, InaC, and HSP60-based LISA showed sensitivity of 92.8, 88.8, 90.4, and 94.4%, and specificity of 99.2, 99.2, 99.2, and 92%, respectively. ROC analysis indicated that Pgp3-based LISA showed similar performance to Mikrogen ELISA (AUC 0.986 vs. 0.993, p = 0.207). Furthermore, four C. trachomatis antigens achieved strong diagnostic efficiency, i.e., positive likelihood ratios [+LR] ≥ 10 in C. trachomatis-infected women and negative likelihood ratios [-LR] ≤ 0.1 in C. trachomatis negative low exposure risk children, but only Pgp3 and TmeA showed strong diagnostic value in general adults. In addition, Pgp3, TmeA, and InaC, but not HSP60, achieved high performance, i.e., both positive predictive value (PPV) and negative predictive value (NPV) ≥ 90.9%, and showed no significant cross-reactivity with anti-Chlamydiapneumoniae. Conclusion Three C. trachomatis species-specific antigens Pgp3, TmeA, and InaC show superior performance in the detection of anti-C. trachomatis antibody, indicating the potential to be used in developing C. trachomatis serologic tests.
Collapse
Affiliation(s)
- Yulian Pang
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| | - Jingwei Shui
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
- Department of Emergency, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Changchang Li
- Dermatology Hospital of Southern Medical University, Guangzhou, China
| | - Yongzhi Li
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| | | | - Shixing Tang
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| |
Collapse
|
3
|
Soto Brito Y, Fonseca Castro DA, Guilarte Garcia E, Kouri Cardellá V, Ramirez Cardentey C, Mondeja Rodriguez BA, Concepción López JJ, Sánchez Alvarez MDL, López Pérez M, Gutierrez Coronado T, Torres Mosqueda K, Suárez Licor G. Chlamydia trachomatis infection in Cuban adolescent and young populations. Int J STD AIDS 2023; 34:1024-1033. [PMID: 37607391 DOI: 10.1177/09564624231191568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
BACKGROUND In Cuba, little is known regarding the prevalence of Chlamydia trachomatis (CT) infection in adolescents and young people. We study the frequency of CT infection in these populations, and its association with clinical-epidemiological variables. METHODS A total of 496 individuals aged 12 to 24 were recruited from November 2018 to November 2019. Of them, 302 were patients attending at sexually transmitted infections (STI) services and 194 were young volunteers. CT detections were carried out by real-time PCR and IgG serology. RESULTS The prevalence of CT using PCR was 9.1% (45/496); 12.3% (37/302) for subjects attending STI service and 4.1% (8/194) for young volunteers, being significantly higher in the first group (OR=3.25; p=.001). CT IgG antibodies was detected in 38.6% (81/210). Individuals from 12 to 17 years old were more likely infected with CT (OR=2.21; p=.010). Infection was associated with the early onset of sexual intercourse, the frequent changing of sexual partners and black ethnicity. CONCLUSIONS The results suggest that Cuban adolescents and young populations are at highest risk of acquiring CT infection and developing reproductive complications. The data obtained advise the needs of implementation of a routine CT screening strategy, for timely diagnosis, detection and treatment at the earliest ages.
Collapse
Affiliation(s)
- Yudira Soto Brito
- Sexually Transmitted Infections Laboratory, Department of Virology, "Pedro Kourí" Tropical Medicine Institute (IPK), Havana, Cuba
| | - Darien Alejandro Fonseca Castro
- Sexually Transmitted Infections Laboratory, Department of Virology, "Pedro Kourí" Tropical Medicine Institute (IPK), Havana, Cuba
| | - Elias Guilarte Garcia
- Sexually Transmitted Infections Laboratory, Department of Virology, "Pedro Kourí" Tropical Medicine Institute (IPK), Havana, Cuba
| | - Vivian Kouri Cardellá
- Sexually Transmitted Infections Laboratory, Department of Virology, "Pedro Kourí" Tropical Medicine Institute (IPK), Havana, Cuba
| | - Celeste Ramirez Cardentey
- Sexually Transmitted Infections Laboratory, Department of Virology, "Pedro Kourí" Tropical Medicine Institute (IPK), Havana, Cuba
| | | | | | | | - Maida López Pérez
- Mariana Grajales" Gyneco-obstetric University Hospital, Santa Clara, Cuba
| | | | | | | |
Collapse
|
4
|
Li P, Chen Z. Association between serum Chlamydia trachomatis antibody levels and infertility among reproductive-aged women in the U.S. Front Public Health 2023; 11:1117245. [PMID: 37089503 PMCID: PMC10113615 DOI: 10.3389/fpubh.2023.1117245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 03/21/2023] [Indexed: 04/25/2023] Open
Abstract
Introduction Chlamydia trachomatis infection, the most prevalent sexually transmitted bacterial infection worldwide, is a significant cause of infertility. Many countries have introduced the widespread use of serologic assays for IgG seropositivity to chlamydial plasmid gene product 3 (Pgp3). However, data on the association between the level of Pgp3-IgG in the multiplex bead array assay (Pgp3AbMBA) and female infertility are still scarce. Methods This cross-sectional analysis included 1,425 women from the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016. Results In the fully adjusted logistic regression model, each standard deviation increments of Pgp3AbMBA (SD = 17,079.63) led to a 28% increase in the risk of infertility. The relationship remained consistent in women who had been pregnant and women who gave birth. Smooth curve fitting revealed that the association was linear across the entire range of Pgp3AbMBA. Subgroup analysis suggested that the association was significantly stronger in women who had ever used marijuana and lived in poverty. Conclusions This study revealed a linear and independent association between the level of Pgp3AbMBA and self-reported infertility in U.S. women. Furthermore, we found that women who had ever used marijuana and lived in poverty were at the highest risk of infertility upon chlamydial infection.
Collapse
|
5
|
Petersen MR, Patel EU, Grabowski MK, Gaydos CA, Quinn TC, Tobian AAR. Seroprevalence of Chlamydia trachomatis Among Female Adults in the United States: The National Health and Nutrition Examination Surveys. Clin Infect Dis 2021; 73:e629-e637. [PMID: 33367598 DOI: 10.1093/cid/ciaa1879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Chlamydia trachomatis is the most common nationally notifiable sexually transmitted infection in the United States; however, the seroprevalence of C. trachomatis infection is unknown. METHODS This cross-sectional study was conducted among 1725 females aged 18 to 39 years who provided serum and urine samples in the 2013 through 2016 National Health and Nutrition Examination Surveys. Presence of anti-C. trachomatis Pgp3 immunoglobulin G (IgG) was determined using both an enzyme-linked immunosorbent assay (ELISA) and multiplex bead array (MBA). Weighted seroprevalence estimates were calculated. Correlates of seroprevalence were examined by multivariable Poisson regression. RESULTS In 2013 through 2016, overall seroprevalence of C. trachomatis Pgp3 IgG was 30.0% (95% confidence interval [CI], 25.5-35.0) as measured by ELISA and 29.4% (95% CI, 25.8-33.0) as measured by the MBA assay. Overall agreement between tests was 87.1% (1503/1725). There was a high positive agreement by the MBA assay with current detection of chlamydia in urine (86% [36/42]), a past-year diagnosis of chlamydia (81.8% [27/33]), and a history of treatment for pelvic inflammatory disease (60.7% [37/61]). Seroprevalence of C. trachomatis Pgp3 IgG, as measured by MBA, was significantly higher among non-Hispanic Blacks (68.0%; adjusted prevalence ratio (aPR) = 2.7 [95% CI, 2.3-3.3]), Mexican Americans (30.9%; aPR = 1.5 [95% CI, 1.2-1.9]), and other Hispanics (35.0%; aPR = 1.9 [95% CI, 1.4-2.5]) compared with non-Hispanic Whites (21.4%). A higher lifetime number of sexual partners and a younger age at sexual debut was also associated with higher seroprevalence. CONCLUSION Both the ELISA and MBA serologic assays revealed a high prevalence of antibodies to C. trachomatis Pgp3 in young adult females in the US household population. There were major racial/ethnic disparities in exposure to C. trachomatis, with increased vulnerability among non-Hispanic Black females.
Collapse
Affiliation(s)
- Molly R Petersen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Eshan U Patel
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - M Kate Grabowski
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Charlotte A Gaydos
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Thomas C Quinn
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Laboratory of Immunoregulation, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, Baltimore, Maryland, USA
| | - Aaron A R Tobian
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
6
|
Gupta K, Harrison SA, Davis NA, Culp ML, Hand SC, Simpson T, Van Der Pol B, Galbraith JW, Van Wagoner NJ, Morrison SG, Morrison RP, Geisler WM. Prevalence of Chlamydia trachomatis Infection in Young Women and Associated Predictors. Sex Transm Dis 2021; 48:529-535. [PMID: 34110759 PMCID: PMC8847232 DOI: 10.1097/olq.0000000000001372] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Chlamydia trachomatis (CT) infection remains highly prevalent, and young women are disproportionately affected. Most CT-infected women are asymptomatic, and their infection often goes unrecognized and untreated. We hypothesized that testing for active CT infection with molecular diagnostics and obtaining a reported history of CT infection underestimate the prevalence of current and past CT infection, and incorporating serum CT antibody testing in addition to these other prevalence measures would generate more accurate estimates of the prevalence of CT infection in asymptomatic young women. METHODS We enrolled 362 asymptomatic women aged 16 to 29 years at 4 different clinical settings in Birmingham, AL, between August 2016 and January 2020 and determined the prevalence of CT infection based on having 1 or more of the following prevalence measures: an active urogenital CT infection based on molecular testing, reported prior CT infection, and/or being CT seropositive. Multivariable regression analysis was used to determine predictors of the prevalence of CT infection after adjustment for participant characteristics. RESULTS The prevalence of CT infection was 67.7% (95% confidence interval, 62.6%-72.5%). Addition of CT antibody testing to the other individual prevalence measures more than doubled the CT infection prevalence. Non-Hispanic Black race, reported prior gonorrhea, and reported prior trichomoniasis predicted a higher prevalence of CT infection. CONCLUSIONS More than half of women were unaware of ever having CT infection, suggesting many were at risk for CT-associated reproductive complications. These data reinforce the need to adhere to chlamydia screening guidelines and to increase screening coverage in those at risk.
Collapse
Affiliation(s)
- Kanupriya Gupta
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sally A. Harrison
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nkele A. Davis
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Matilda L. Culp
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Samuel C. Hand
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tina Simpson
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Barbara Van Der Pol
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - James W. Galbraith
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Emergency Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicholas J. Van Wagoner
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sandra G. Morrison
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Richard P. Morrison
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - William M. Geisler
- School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| |
Collapse
|
7
|
Danavall DC, Gwyn S, Anyalechi GE, Bowden KE, Hong J, Kirkcaldy RD, Bernstein KT, Kersh EN, Martin D, Raphael BH. Assessment and utility of 2 Chlamydia trachomatis Pgp3 serological assays for seroprevalence studies among women in the United States. Diagn Microbiol Infect Dis 2021; 101:115480. [PMID: 34325205 DOI: 10.1016/j.diagmicrobio.2021.115480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/27/2022]
Abstract
Two plasmid gene protein (Pgp3)-based serological assays, the Pgp3-ELISA and multiplex bead assay (Pgp3-MBA), were compared and used to estimate seropositivity of Chlamydia trachomatis (CT) among females 14 to 39 years old participating in the National Health and Nutrition Examination Survey between 2013-2016. Of the 2,201 specimens tested, 502 (29.5%, 95% CI 27.6-31.5) were positive using Pgp3-ELISA and 624 (28.4%, 95% CI 26.5-30.3) were positive using Pgp3-MBA. The overall agreement between the assays was 87.7%. Corresponding nucleic acid amplification test (NAAT) results were available for 1,725 specimens (from women 18-39 years old); of these, 42 (2.4%, 95% CI 1.8-3.3) were CT NAAT-positive. Most of the CT NAAT-positive specimens had corresponding positive serological assay results; 33 (78.6%, 95% CI 62.8-89.2) were Pgp3-ELISA-positive and 36 (85.7%, 95% CI 70.8-94.1) were Pgp3-MBA-positive. Although Pgp3-ELISA and Pgp3-MBA demonstrated equivalent performance in this study, an advantage of the Pgp3-MBA over Pgp3-ELISA is that it is well suited for high sample throughput applications.
Collapse
Affiliation(s)
- Damien C Danavall
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Gloria E Anyalechi
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Katherine E Bowden
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jaeyoung Hong
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Robert D Kirkcaldy
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kyle T Bernstein
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ellen N Kersh
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Diana Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Brian H Raphael
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| |
Collapse
|
8
|
Anyalechi GE, Hong J, Danavall DC, Martin DL, Gwyn SE, Horner PJ, Raphael BH, Kirkcaldy RD, Kersh EN, Bernstein KT. High Pgp3 Chlamydia trachomatis seropositivity, pelvic inflammatory disease and infertility among women, National Health and Nutrition Examination Survey, United States, 2013-2016. Clin Infect Dis 2021; 73:1507-1516. [PMID: 34050737 DOI: 10.1093/cid/ciab506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Chlamydia trachomatis causes pelvic inflammatory disease (PID) and tubal infertility. Pgp3 antibody (Pgp3Ab) detects prior chlamydial infections. We evaluated for an association of high chlamydial seropositivity with sequelae using a Pgp3Ab multiplex bead array (Pgp3AbMBA). METHODS We performed chlamydia Pgp3AbMBA on sera from women 18-39 years old participating in the 2013-2016 National Health and Nutrition Examination Survey (NHANES) with urine chlamydia nucleic acid amplification test results. High chlamydial seropositivity was defined as a median fluorescence intensity (MFI ≥ 50,000; low-positive was MFI > 551-<50,000. Weighted US population high-positive, low-positive, and negative Pgp3Ab chlamydia seroprevalence and 95% confidence intervals (95% CI) were compared for women with chlamydial infection, self-reported PID, and infertility. RESULTS Of 2,339 women aged 18-39 years, 1,725 (73.7%) had sera and 1,425 were sexually experienced. Overall, 104 women had high positive Pgp3Ab (5.4% [95% CI 4.0-7.0] of US women); 407 had low positive Pgp3Ab (25.1% [95% CI 21.5-29.0]), and 914 had negative Pgp3Ab (69.5% [95% CI 65.5-73.4]).Among women with high Pgp3Ab, infertility prevalence was 2.0 (95% CI 1.1-3.7) times higher than among Pgp3Ab-negative women (19.6% [95% CI 10.5-31.7] versus 9.9% [95% CI 7.7-12.4]). For women with low Pgp3Ab, PID prevalence was 7.9% (95% CI 4.6-12.6) compared to 2.3% (95% CI 1.4-3.6) in negative Pgp3Ab. CONCLUSIONS High chlamydial Pgp3Ab seropositivity was associated with infertility although small sample size limited evaluation of an association of high seropositivity with PID. In infertile women, Pgp3Ab may be a marker of prior chlamydial infection.
Collapse
Affiliation(s)
- Gloria E Anyalechi
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jaeyoung Hong
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Damien C Danavall
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Sarah E Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Patrick J Horner
- Population Health Sciences and National Institute for Health Research, Health Protection Research Unit in Behavioural Science and Evaluation in Partnership with Public Health England, University of Bristol, Bristol, UK
| | - Brian H Raphael
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Robert D Kirkcaldy
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ellen N Kersh
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kyle T Bernstein
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| |
Collapse
|