Epidemiologic Basis of STD Control: Introduction and STD Surveillance. Jonathan Zenilman, MD Johns Hopkins University

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2 Epidemiologic Basis of STD Control: Introduction and STD Surveillance Jonathan Zenilman, MD Johns Hopkins University

3 Section A Background on STDs

4 STDs: Background 15 million cases annually in the U.S. Predominantly adolescents and young adults Major cause of Morbidity and Mortality in developed and developing countries Other issues women s health, child health, association with HIV Stigma 4

5 Sexual Health Sexual health is a state of physical, emotional, mental, and social wellbeing in relation to sexuality; it is not merely the absence of disease, dysfunction, or infirmity. Sexual health needs a positive and respectful approach to sexuality and sexual relationships, and the possibility of having pleasurable and safe sexual experiences that are free of coercion,discrimination, and violence. For sexual health to be attained and maintained, the sexual rights of all individuals must be respected, protected, and satisfied. 5

6 Overview of Complications of STDs 6

7 Combined Frequency of Infection of Four Curable STIs: Gonorrhea, Chlamydia, Syphilis, and Trichomonas Source: Figure 3. Glasier A, et al. Sexual and reproductive health: a matter of life and death. Lancet 2006;368(9547): Copyright 2006 Elsevier Ltd. All Rights Reserved. 7

8 Events and Outcomes: Costs and Morbidity of Sexual Behavior Unintended pregnancy Low birth weight infants Terminations STD direct costs-medical (PID) Long-term STD costs (ectopics, infertility) Emotional and economic costs Potentiated HIV risk (three to six times the risk) 8

9 The IOM Report of 1997: The Hidden Epidemic Despite the tremendous health and economic burden of STDs, the scope and impact of the STD epidemic are underappreciated and the STD epidemic is largely hidden from public discourse. Public awareness and knowledge regarding STDs are dangerously low, but there has not been a comprehensive national public education campaign to address this deficiency. 9

10 Section B STD Surveillance: General Principles

11 Assessment Systematically collect, assemble, analyze, and make available information on the health of the community, including statistics on health status, community health needs, and epidemiological and other studies of health problems Source: Institute of Medicine,

12 Disease Surveillance: Objectives Determine trends of incidence and prevalence Provide strategic direction to disease prevention and medical care programs Provide baseline data for evaluation Identify sentinel events for public health action 12

13 Disease Reporting Issues: STDs Public/private biases Classification of contacts Case definitions syndromic treatment Resource availability Funding stream Timeliness 13

14 STD Surveillance Challenges Identify the appropriate outcomes/measurements Prevalent vs. incident disease Do you have to count every case? Clinical/syndromic case definitions Variable needs in different areas 14

15 Incubation Periods Gonorrhea days Chlamydia weeks HPV three to six months HIV three to six weeks Syphilis three to six weeks Trichomonas days 15

16 Incident STDs Typically bacterial infections which are curable Short incubation period Often symptomatic Susceptible to reinfection after treatment Examples gonorrhea, syphilis, chancroid 16

17 Estimated Burden of STIs in Society Source: Figure 4. Glasier A, et al. Sexual and reproductive health: a matter of life and death. Lancet 2006;368(9547): Copyright 2006 Elsevier Ltd. All Rights Reserved. 17

18 Prevalent STDs Usually chronic viral infections Incident infection difficult to detect Cross-sectional studies identify prevalent disease, usually with specific serology assays Often long latency period Examples HIV, herpes simplex, CMV 18

19 HSV-2 Seroprevalence in the United States 25 Prevalence (%) AW Source: Fleming, P. (1997), NEJM; CDC National Meeting,

20 Prevalent Infections: The Control Challenge Strategy based on prevalent data Time trajectory often not known Evaluation of interventions is methodologically difficult Use of surrogate (e.g., behavioral) markers for evaluation 20

21 Section C Syphilis STD Reflecting Social Trends

22 Primary and Secondary Syphilis Rates: U.S., and the Healthy People 2010 Target Rate (per 100,000 population) P&S Syphilis 2010 Target Note: The Healthy People 2010 target for P&S syphilis is 0.2 case per 100,000 population 22

23 Primary and Secondary Syphilis (Rates by Race/ Ethnicity): U.S., Figure 32. STD Surveillance CDC 23

24 Syphilis in the U.S.: 1940s 24

25 Syphilis in the U.S.: 1940s 25

26 Primary and Secondary Syphilis (Rates by State): U.S. and Outlying Areas, Guam Rate per 100,0 population <= >8 VT NH MA RI CT NJ DE MD 0.3 Puerto Rico 4.6 Virgin Is. 6.4 Note: The total rate of primary and secondary syphilis for the United States and outlying areas (including Guam, Puerto Rico and Virgin Islands) was 2.6 per 100,000 population. The Healthy People year 2000 objective is 4.0 per 100,000 population. STD Surveillence CDC 26

27 Primary and Secondary Syphilis (Rates by State): U.S. and Outlying Areas, 2005 Figure 29. STD Surveillance CDC 27

28 Primary and Secondary Syphilis (Cases by Reporting Source and Sex): U.S., Figure 31. STD Surveillance CDC 28

29 Primary and Secondary Syphilis (Male-to-Female Rate Ratios): U.S., Male-Female rate ratio 10:1 8:1 6:1 4:1 2: STD Surveillance CDC 29

30 Incidence of Total Syphilis in 2005 by Province Numbers in parentheses show number of provinces in band Figure 4. Chen et al. Syphilis in China: results of a national surveillance programme. Lancet 2007;369:

31 Section D GIS as an Applied Tool

32 GIS Application: The Baltimore Syphilis Epidemic In there was a large syphilis epidemic in Baltimore GIS mapping was used to describe the outbreak The outbreak was characterized by endemic and spread areas 32

33 Pathways of STD Every time someone in Baltimore comes to a public clinic for treatment of syphilis or gonorrhea, John Zenilman plugs his or her address into his computer, so that the case shows up as a little black star on a map of the city. It's rather like a medical version of the maps police departments put up on their walls, with pins marking where crimes have occurred. On Zenilman's map the neighborhoods of East and West Baltimore, on either side of the downtown core, tend to be thick with black stars. From those two spots, the cases radiate outward along the two central roadways that happen to cut through both neighborhoods. In the summer, when the incidence of sexually transmitted disease is highest, the clusters of black stars on the roads leading out of East and West Baltimore become thick with cases. The disease is on the move. But in the winter months, the map changes. When the weather turns cold, and the people of East and West Baltimore are much more likely to stay at home, away from the bars and clubs and street corners where sexual transactions are made, the stars in each neighborhood fade away. 33

34 Reported Primary and Secondary Syphilis Rates by Year: (Projection) Rate per 100, Baltimore US * * Projected 2004 rate; 2003 and 2004 U.S. are rates unavailable Source: Baltimore City Health Department, STD Surveillance Unit (July, 2004) 34

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44 Gonorrhea (Rates by Race and Ethnicity): U.S., and the Healthy People 2010 Objective Rate (per 100,000 population) 2,500 2,000 1,500 White Black Hispanic Asian/Pac Isl Am Ind/AK Nat 2010 Objective 1,

45 Gonorrhea (Rates by State): U.S. and Outlying Areas, 2005 Figure 29. STD Surveillance CDC 45

46 Defining Population Based STD Prevalence in Baltimore Health department reports are biased towards symptomatic disease cases seeking care Private sector/public sector reporting bias Development of new nucleic acid based tests (NAATS) Gaydos, Quinn; facilitate population assessments 46

47 Geographic Distribution of STDs STDs are not equally distributed across neighborhoods Studies in Colorado Springs, Dade County, North Carolina, Miami, San Francisco, and Baltimore show similar findings Development of mapping and GIS tools have facilitated this area of study Most governments now have active GIS units 47

48 Gonorrhea Rate Categories by Census Block Group in Baltimore, MD, = GC 5,000-1,039 per 100,000 = GC 1, per 100,000 = GC per 100,000 48

49 Gonorrhea Rate Per 100,000 by Census Block Group in Baltimore, MD,

50 Prevalence of STDs in Baltimore? What is the true population prevalence of STDs in Baltimore? Charles F. Turner; Susan M. Rogers; Heather G. Miller; William C. Miller; James N. Gribble; James R. Chromy; Peter A. Leone; Phillip C. Cooley; Thomas C. Quinn; Jonathan M. Zenilman. Untreated Gonococcal and Chlamydial Infection in a Probability Sample of Adults. JAMA : OBJECTIVE: To estimate the overall prevalence of untreated gonococcal and chlamydial infections and to describe patterns of infection within specific demographic subgroups of the young adult population in Baltimore, Md. 50

51 Probability Sample of Baltimore City Adults 1,014 adults Probability sample of residences from tax rolls Random selection within household 45 minute survey + LCR testing Crude response rate 71% Oversamples white CTs with high STDs, males in black CTs 51

52 Weighted Estimates (Standard Error) of GC/CT Prevalence in Baltimore, Disease Gender Black White Chlamydia Gonorrhea Female 6.4 (2.2) 0 Male 1.1 (0.7) 2.4 (1.3) Female 9.3 (3.3) 1.3 (0.5) Male 5.3 (2.0) 1.3 (0.5) Source: Turner C, et al. Untreated Gonococcal and Chlamydial Infection in a Probability Sample of Adults. JAMA :

53 Citywide Estimates: Gonorrhea 4,566 cases reported in 1998 (2.6% prevalence) Survey self reported estimate: 4,708 (2.7%) - 5,231 (3.0%) NAAT-positive at time of survey 9,241 persons infected (5.3%) 53

54 Policy Conclusions An estimated % of the population has untreated GC or CT Nearly all infections were asymptomatic Prevalence is greater than three times that estimated from Baltimore City Health Department statistics Baltimore likely represents a best case for STD surveillance data reporting RTI colleagues funded for second surveillance study 54

55 Section E Chlamydia Surveillance Issues

56 Cross-Over STDs Chlamydia and trichomonas Both curable May be asymptomatic for prolonged periods of time Have epidemiological characteristics of incident and prevalent infection There are large surveillance and control programs in place for chlamydia due to large scale support for testing 56

57 Chlamydia (Rates by Sex): United States, Rate (per 100,000 population) Men Women Source: STD Surveillance CDC. 57

58 Chlamydia (Rates by County): United States (2003) Rate per 100,000 population <=150.0 (N= 1,498) (N= 939) >300.0 (N= 703) Source: STD Surveillance CDC. 58

59 Outcome Measurements: Disease Acute Gonorrhea/chlamydia Pelvic inflammatory disease HPV Chronic Infertility Ectopic pregnancy Cervical cancer (HIV) 59

60 Section F STD Surveillance-Operational Issues

61 Sources of Surveillance STD Data Health department data Community surveys National databases Hospital databases Payor data (Medicaid, etc.) 61

62 Pelvic Inflammatory Disease: Hospitalization of Women 15 to 44 Years of Age: U.S., Note: The relative standard error for these estimates of the total number of acute unspecified PID cases range from 8% to 11%. 62

63 STD Surveillance Data Flow Provider County or City Health Dept State Health Dept Lab ESS MMWR Other Publications CDC Data Warehouse 63

64 Reporting Structure of China s Nationwide STD Surveillance System 64

65 STD Behavioral Surveillance New issue Need for baseline data Identification of high risk groups for intervention Validity/reliability issues Objective assess intervention effectiveness and secular behavioral trends 65

66 Sources of Behavioral Surveillance Data Qualitative surveys Population-specific STD clinics, jails Cross sectional Telephone surveys (BRFSS) Face to face surveys (NHANES) ACasi 66

67 Bias Issues Population selection YRBSS Population specific Response differential Phone surveys have major selection issues because of technology Ascertainment bias Reporting bias 67

68 Sexual Behavior Events Age of sexual debut Numbers of partners serial/concurrent Condom use patterns HIV risk profiles Other co-morbidities Drug use, economic impact, commercial sex, travel 68

69 Structural Influences on Behavior and STI Risk Status of women Migration (internal and external) Gender ratio (e.g., China, Baltimore) Age at marriage Religious/social norms External stress (e.g. war, conflict) Economic issues (Macro and Micro) Public health efforts Behavioral Clinical 69

70 Condom Use at Last Sex: GSS Regular Casual/New Source: Adapted from Anderson JE, et al. Changes in HIV-Related Preventive Behavior in the US Population: Data From National Surveys, (2003), JAIDS; 34:

71 Male Condom Use at Last Sex with a Non-Regular (Non-Marital, Non-Cohabiting) Partner 71

72 Percentage of High School Students Currently Sexually Active* by Sex and Race/Ethnicity** (2005) Percent Total Female Male White Black Hispanic * Had sexual intercourse with 1 persons during the 3 months preceding the survey ** B > W, H Source: National Youth Risk Behavior Survey (2005). CDC 72

73 Percentage of High School Students Who Were Currently Sexually Active* ( ) Percent * Had sexual intercourse with 1 persons during the three months preceding the survey 1 Significant linear decrease, P <.05 Source: National Youth Risk Behavior Surveys ( ). CDC 73

74 High School Students Who Used a Condom During Last Sexual Intercourse* by Sex** and Race/Ethnicity*** (2005) 100 Percent Total Female Male White Black Hispanic * Among the 33.9% of students nationwide who had sexual intercourse with one or more persons during the three months preceding the survey ** M > F *** B > W > H Source: National Youth Risk Behavior Survey (2005). CDC. 74

75 Percentage of High School Students Who Used a Condom During Last Sexual Intercourse* ( ) Percent * Among students who had sexual intercourse with one or more persons during the three months preceding the survey 1 Significant linear increase, P <.05 Source: National Youth Risk Behavior Surveys, CDC. 75

76 Section G STD Surveillance-Specific Populations

77 STD Surveillance-Specific Populations: Determining Disease Prevalence Population-based survey methods Statistical (NHANES) vs. convenience samples (GISP) New diagnostic methods for clinical and population-based surveys Urine STD diagnostics LCR/PCR Oral HIV tests Serial serological surveys 77

78 National Surveys: STD/HIV as Outcomes Not part of surveys until 1988 Surveys since have included mostly STD self-report Biological measures in NHANES (HSV, RPRs), NSAM (urine for GC, chlamydia) Recent advances include urine tests for GC, chlamydia, saliva HIV tests, self-administered vaginal swabs 78

79 Military STD Surveillance Issues At-risk population Mobile population Universal health care access Interaction with communities Interaction with other servicemen/women 79

80 Surveillance and Managed Care Movement of traditional STD populations into managed care (Medicaid) Role of public health laboratories MCO model often not oriented to disease surveillance Syndromic patient management 80

81 Antimicrobial Resistance Surveillance A need for standardized susceptibility determinations (MIC from culture) Developed multicenter approach in 1986 Adopted in EU, Asia, Australia Collect behavioral and biological data 81

82 Principles of GISP Standardized lab procedures including Q/A Standardized reagents Resistance definitions and clinical action thresholds Systematic collection of isolates (first 25 males in participating clinics) 82

83 Laboratory-Based Surveillance Resistance tracking Plasmid or subtype analysis Confirmation of clinical algorithms Confirmation of surveillance definitions 83

84 Gonococcal Isolate Surveillance Project (GISP): Location of Participating Clinics and Regional Laboratories: U.S., 2003 Seattle Portland San Francisco Denver Los Angeles Long Beach Orange Co. San Diego Phoenix Anchorage Las Vegas Salt Lake City Albuquerque Tripler AMC Honolulu Minneapolis Oklahoma City Detroit Philadelphia Chicago Cleveland Cincinnati Baltimore St.Louis Birmingham Dallas New Orleans STD Clinics Clinics and Regional Labs Greensboro Atlanta Miami Gonococcal Isolate Surveillance Project (GISP). CDC. 84

85 GISP: Neisseria Gonorrhea Isolates with Resistance or Intermediate Resistance to Ciprofloxacin, Percent Resistance Intermediate resistance Note: Resistant isolates have ciprofloxacin MICs μg/ml. Isolates with intermediate resistance have ciprofloxacin MICs of μg/ml. Susceptibility to ciprofloxacin was first measured in GISP in GISP 2004 Surveillance Supplement. CDC. 85

86 Conclusions Trend analysis is critical for effective STD surveillance Focused/sentinel STD surveillance approaches are cheaper and easier New diagnostic test technology facilitates field activities Core group approaches may be warranted 86