The interrelation of demographic and geospatial risk factors between four common sexually transmitted diseases

Prevalence and Epidemiological Characteristics of Anogenital Warts Among Recently Diagnosed HIV-Positive Women on Antiretroviral Therapy in Lagos, Nigeria

Background Anogenital warts (AGWs) are a prevalent condition resulting from human papillomavirus (HPV) infection, which is the most frequently encountered sexually transmitted infection (STI) on a global scale. Women who are HIV-positive experience a disproportionately high burden of AGWs compared to other populations. It is imperative to comprehend the epidemiological factors linked to the disease within this particular at-risk population. Objectives The objective of the study was to ascertain the prevalence of AGWs and its demographic and socio-biological epidemiological features among recently diagnosed HIV-positive women (HPW) in Lagos, Nigeria. Materials and methods The research was a descriptive cross-sectional study conducted among a sample of 420 recently diagnosed HPW. The study was conducted at the HIV clinic of a tertiary health institution located in Lagos, Nigeria. The participants clinically diagnosed with AGWs were classified as the study group, while individuals without AGWs were classified as the comparison group. Interviewer-administered pretested questionnaires were utilized to gather pertinent demographic and socio-biological epidemiological data from the participants involved in the study. The data were analyzed using IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, USA). Results The prevalence of AGWs among recently diagnosed HPW was found to be 8.5% (34/402). These warts were frequently observed on the vulvar labia (35.3%, 12/34), vaginal walls (14.7%, 5/34), and perianal region (14.7%, 5/34). It is worth noting that over a third of cases (35.3%, 12/34) involved multiple areas within the anogenital region. The diagnosis of AGWs was found to have significant associations with occupation (p=0.005), marital status (p<0.001), and educational status (p=0.028). The majority of HPW diagnosed with AGWs were unemployed (32.4%, 11/34), single (47.1%, 16/34), and did not have tertiary education (94.1%, 32/34). The utilization of oral contraceptive pills (OCPs), smoking, low CD4 count, and high viral load were the significant socio-biological factors associated with the diagnosis of AGWs (p<0.001, respectively). Conclusion The study found that the prevalence of AGW among HPW was 8.5% (34/402). Several epidemiological factors, including occupation, marital status, education, CD4 count, viral load, history of OCP use, and smoking, were found to be significantly associated with the diagnosis of AGW. There is a need to conduct more comprehensive studies to thoroughly assess the impact of these epidemiological factors.

Quantifying heterogeneity in sexual behaviour and distribution of STIs before and after pre-exposure prophylaxis among men who have sex with men

Objectives: Pre-exposure prophylaxis (PrEP) use may influence sexual behaviour and transmission of STIs among men who have sex with men (MSM). We aimed to quantify the distribution of STI diagnoses among MSM in the Netherlands based on their sexual behaviour before and after the introduction of PrEP.Methods: HIV-negative MSM participating in a prospective cohort study (Amsterdam Cohort Studies) completed questionnaires about sexual behaviour and were tested for STI/HIV during biannual visits (2009-2019). We developed a sexual behaviour risk score predictive of STI diagnosis and used it to calculate Gini coefficients for gonorrhoea, chlamydia and syphilis diagnoses in the period before (2009 to mid-2015) and after PrEP (mid-2015 to 2019). Gini coefficients close to zero indicate that STI diagnoses are homogeneously distributed over the population, and close to one indicate that STI diagnoses are concentrated in individuals with a higher risk score.Results: The sexual behaviour risk score (n=630, n visits=10 677) ranged between 0.00 (low risk) and 3.61 (high risk), and the mean risk score increased from 0.70 (SD=0.66) before to 0.93 (SD=0.80) after PrEP. Positivity rates for chlamydia (4%) and syphilis (1%) remained relatively stable, but the positivity rate for gonorrhoea increased from 4% before to 6% after PrEP. Gini coefficients increased from 0.37 (95% CI 0.30 to 0.43) to 0.43 (95% CI 0.36 to 0.49) for chlamydia, and from 0.37 (95% CI 0.19 to 0.52) to 0.50 (95% CI 0.32 to 0.66) for syphilis comparing before to after PrEP. The Gini coefficient for gonorrhoea remained stable at 0.46 (95% CI 0.40 to 0.52) before and after PrEP.Conclusions: MSM engaged in more high-risk sexual behaviour and gonorrhoea diagnoses increased after PrEP was introduced. Chlamydia and syphilis diagnoses have become more concentrated in a high-risk subgroup. Monitoring the impact of increasing PrEP coverage on sexual behaviour and STI incidence is important. Improved STI prevention is needed, especially for high-risk MSM.

Changes in self-reported sexually transmitted infections and symptoms among married couples in India from 2006 to 2016: a repeated cross-sectional multivariate analysis from nationally representative data

OBJECTIVE

To assess the changes in prevalence of past-year self-reported sexually transmitted infections (STIs) and its symptoms among married couples between 2006 and 2016 in India, overall and by socioeconomic status.

DESIGN

This cross-sectional study uses the two most recent waves (2005-2006 vs 2015-2016) of nationally representative health surveys in India. We examined the changes of self-reported STI and symptoms among married couples aged 15-54 by overall and by socioeconomic status. Adjusted logistic regression was used to assess the changes, accounting for covariates and the complex survey design.

SETTING

Cross-sectional, nationally representative population-based survey in 2005-2006 and 2015-2016 from National Family Health Survey data from Demographic and Health Survey.

PARTICIPANTS

39 257 married couples aged 15-49 years for the 2005-2006 survey wave and 63 696 married couples aged 15-49 years for the 2015-2016 wave.

OUTCOME MEASURE

Self-reported STI was used as a primary outcome measure.

RESULTS

In 2016, 2.5% of married women reported having had an STI in the past year, a significant increase from 1.6% in 2006 (p<0.001). The past-year self-reported STI prevalence among married men significantly increased from 0.5% in 2006 to 1.1% in 2016 (p<0.001). Adjusted results showed that the uptrend of couples' self-reported STI was more significant among those whose husbands are currently employed and those families in middle or higher wealth quintiles. Alarmingly, among couples who reported STI or symptoms, they were less likely to seek advice or treatment in 2016 as compared with 2006 (adjusted OR=0.50, p<0.001, 95% CI=0.40 to 0.61).

CONCLUSION

The study identifies a substantial increase in self-reported STI prevalence with a notable treatment seeking gap among married couples in India over the past decade.

Increase in Gonorrhea Incidence Associated With Enhanced Partner Notification Strategy

OBJECTIVES

Partner notification services for reportable sexually transmitted infections vary based on jurisdiction, resources, type of infection, and whether an outbreak has been reported. The objective of this study was to determine whether case finding increased after implementation of enhanced notification and follow-up activities for contacts of cases of Neisseria gonorrhoeae in Central Zone, the largest health authority in Nova Scotia, Canada.

METHODS

Enhanced contact tracing by public health professionals was implemented in May 2015. N. gonorrhoeae multiantigen sequence typing (NG-MAST) was conducted on all positive specimens. Epidemiologic and NG-MAST information for reported gonorrhea cases were captured and analyzed. Case numbers, rates, and NG-MAST results in the preintervention and postintervention periods were compared. Laboratory testing data were extracted and analyzed for association with reported incidence.

RESULTS

There was a significant increase in the number of reported gonorrhea cases per month when comparing the preintervention and postintervention periods. The reported gonorrhea rate in 2016 was 2.9 times that in 2014. This increase was not associated with changes in testing rates and was more pronounced among women than men. Larger groups of cases sharing the same NG-MAST profiles were detected postintervention.

CONCLUSIONS

The implementation of an enhanced contact tracing program for N. gonorrhoeae resulted in increased case finding and a notable increase in the reported rate of cases per 100,000 population. Owing to these findings, the practice of enhanced partner notification was continued as standard public health practice in Central Zone. An understanding of case finding efforts is required when interpreting observed trends in rates of N. gonorrhoeae, as early infection is highly asymptomatic in women and can be asymptomatic in men.

Gini coefficients for measuring the distribution of sexually transmitted infections among individuals with different levels of sexual activity

Objectives

Gini coefficients have been used to describe the distribution of Chlamydia trachomatis (CT) infections among individuals with different levels of sexual activity. The objectives of this study were to investigate Gini coefficients for different sexually transmitted infections (STIs), and to determine how STI control interventions might affect the Gini coefficient over time.

Methods

We used population-based data for sexually experienced women from two British National Surveys of Sexual Attitudes and Lifestyles (Natsal-2: 1999–2001; Natsal-3: 2010–2012) to calculate Gini coefficients for CT, Mycoplasma genitalium (MG), and human papillomavirus (HPV) types 6, 11, 16 and 18. We applied bootstrap methods to assess uncertainty and to compare Gini coefficients for different STIs. We then used a mathematical model of STI transmission to study how control interventions affect Gini coefficients.

Results

Gini coefficients for CT and MG were 0.33 (95% CI [0.18–0.49]) and 0.16 (95% CI [0.02–0.36]), respectively. The relatively small coefficient for MG suggests a longer infectious duration compared with CT. The coefficients for HPV types 6, 11, 16 and 18 ranged from 0.15 to 0.38. During the decade between Natsal-2 and Natsal-3, the Gini coefficient for CT did not change. The transmission model shows that higher STI treatment rates are expected to reduce prevalence and increase the Gini coefficient of STIs. In contrast, increased condom use reduces STI prevalence but does not affect the Gini coefficient.

Conclusions

Gini coefficients for STIs can help us to understand the distribution of STIs in the population, according to level of sexual activity, and could be used to inform STI prevention and treatment strategies.

Sexual risk reduction interventions for patients attending sexual health clinics: a mixed-methods feasibility study

BACKGROUND

Sexually transmitted infections (STIs) continue to represent a major public health challenge. There is evidence that behavioural interventions to reduce risky sexual behaviours can reduce STI rates in patients attending sexual health (SH) services. However, it is not known if these interventions are effective when implemented at scale in SH settings in England.

OBJECTIVES

The study (Santé) had two main objectives - (1) to develop and pilot a package of evidence-based sexual risk reduction interventions that can be delivered through SH services and (2) to assess the feasibility of conducting a randomised controlled trial (RCT) to determine effectiveness against usual care.

DESIGN

The project was a multistage, mixed-methods study, with developmental and pilot RCT phases. Preparatory work included a systematic review, an analysis of national surveillance data, the development of a triage algorithm, and interviews and surveys with SH staff and patients to identify, select and adapt interventions. A pilot cluster RCT was planned for eight SH clinics; the intervention would be offered in four clinics, with qualitative and process evaluation to assess feasibility and acceptability. Four clinics acted as controls; in all clinics, participants would be consented to a 6-week follow-up STI screen.

SETTING

SH clinics in England.

PARTICIPANTS

Young people (aged 16-25 years), and men who have sex with men.

INTERVENTION

A three-part intervention package - (1) a triage tool to score patients as being at high or low risk of STI using routine data, (2) a study-designed web page with tailored SH information for all patients, regardless of risk and (3) a brief one-to-one session based on motivational interviewing for high-risk patients.

MAIN OUTCOME MEASURES

The three outcomes were (1) the acceptability of the intervention to patients and SH providers, (2) the feasibility of delivering the interventions within existing resources and (3) the feasibility of obtaining follow-up data on STI diagnoses (primary outcome in a full trial).

RESULTS

We identified 33 relevant trials from the systematic review, including videos, peer support, digital and brief one-to-one sessions. Patients and SH providers showed preferences for one-to-one and digital interventions, and providers indicated that these intervention types could feasibly be implemented in their settings. There were no appropriate digital interventions that could be adapted in time for the pilot; therefore, we created a placeholder for the purposes of the pilot. The intervention package was piloted in two SH settings, rather than the planned four. Several barriers were found to intervention implementation, including a lack of trained staff time and clinic space. The intervention package was theoretically acceptable, but we observed poor engagement. We recruited patients from six clinics for the follow-up, rather than eight. The completion rate for follow-up was lower than anticipated (16% vs. 46%).

LIMITATIONS

Fewer clinics were included in the pilot than planned, limiting the ability to make strong conclusions on the feasibility of the RCT.

CONCLUSION

We were unable to conclude whether or not a definitive RCT would be feasible because of challenges in implementation of a pilot, but have laid the groundwork for future research in the area.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16738765.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 12. See the NIHR Journals Library website for further project information.

Prevalence and incidence of genital warts and cervical Human Papillomavirus infections in Nigerian women

BACKGROUND

Genital warts are important causes of morbidity and their prevalence and incidence can be used to evaluate the impact of HPV vaccination in a population.

METHODS

We enrolled 1020 women in a prospective cohort study in Nigeria and followed them for a mean (SD) of 9 (4) months. Nurses conducted pelvic examinations and collected ectocervical samples for HPV testing. We used exact logistic regression models to identify risk factors for genital warts.

RESULTS

The mean age of study participants was 38 years, 56% (535/962) were HIV-negative and 44% (427/962) were HIV-positive. Prevalence of genital warts at enrolment was 1% (4/535) among HIV-negative women, and 5% (23/427) among HIV-positive women. Of 614 women (307 HIV negative and 307 HIV positive women) for whom we could compute genital wart incidence, it was 515 (95% CI:13-2872) per 100,000 person-years in HIV-negative and 1370 (95% CI:283-4033) per 100,000 person-years in HIV-positive women. HIV was associated with higher risk of prevalent genital warts (OR:7.14, 95% CI:2.41-28.7, p < 0.001) while higher number of sex partners in the past year was associated with increased risk of incident genital warts (OR:2.86, 95% CI:1.04-6.47. p = 0.04). HPV11 was the only HPV associated with prevalent genital warts in this population (OR:8.21, 95% CI:2.47-27.3, p = 0.001).

CONCLUSION

Genital warts are common in Nigeria and our results provide important parameters for monitoring the impact of future HPV vaccination programs in the country. HIV infection and number of sexual partners in past year were important risk factors for prevalent and incident genital warts respectively.

Predicting STI Diagnoses Amongst MSM and Young People Attending Sexual Health Clinics in England: Triage Algorithm Development and Validation Using Routine Clinical Data

BACKGROUND

Sexual health (SH) services increasingly need to prioritise those at greatest risk of sexually transmitted infections (STIs). We used SH surveillance data to develop algorithms to triage individuals attending SH services within two high-risk populations: men who have sex with men (MSM) and young people (YP).

METHODS

Separate multivariable logistic regression models for MSM and YP were developed using surveillance data on demographics, recent sexual history, prior STI diagnoses and drug/alcohol use from five clinics in 2015-2016 to identify factors associated with new STI diagnoses. The models were prospectively applied in one SH clinic in May 2017 as an external validation.

FINDINGS

9530 YP and 1448 MSM SH episodes informed model development. For YP, factors associated with new STI diagnosis (overall prevalence: 10.6%) were being of black or mixed white/black ethnicity; history of chlamydia diagnosis (previous year); and multiple partners/new partner (previous 3-months). The YPs model had reasonable performance (c-statistic: 0.703), but poor discrimination when externally validated (c-statistic: 0.539). For MSM, being of South Asian ethnicity; being born in Europe (excluding the UK); and condomless anal sex or drug use (both in previous 3-months) were associated with STI diagnosis (overall prevalence: 22.0%). The MSM model had a c-statistic of 0.676, reducing to 0.579 on validation.

INTERPRETATION

SH surveillance data, including limited behavioural data, enabled triage algorithms to be developed, but its implementation may be problematic due to poor external performance. This approach may be more suitable to self-triage, including online, ensuring patients are directed towards appropriate services.

FUNDING

NIHR HTA programme (12/191/05).

Sociodemographic and geographical inequalities in notifiable infectious diseases in Australia: a retrospective analysis of 21 years of national disease surveillance data

BACKGROUND

Australia is a high-income country with a well established and largely publicly funded health-care system. However, some populations within Australia have shorter life expectancy and worse health outcomes than others. We explored geographical variations and sociodemographic inequities in infectious disease notifications in Australia.

METHODS

In this retrospective study, we analysed National Notifiable Diseases Surveillance System (NNDSS) notifications from 1991-2011 (n=2·4 million). We assessed the effect of socioeconomic disadvantage and remoteness of residence on national notification incidence. We calculated Gini coefficients, adjusted relative risks (aRRs), population attributable fractions (PAFs), and attributable notifications. We reported aRRs for Indigenous status in three jurisdictions with more than 75% completeness of Indigenous status reporting from the Northern Territory, South Australia, and Western Australia.

FINDINGS

Of the eight most commonly notified diseases from Jan 1, 1991, to Dec 31, 2011, gonococcal infection was the most geographically unequal and campylobacteriosis was the most evenly distributed across the country. Overall, notification incidence was higher in remote and very remote areas than in major cities (aRR 3·37), and higher in the most socioeconomically disadvantaged quintiles compared with less disadvantaged quintiles (aRR 1·15). The PAF for socioeconomic disadvantage was high for blood-borne viral hepatitis but decreased in other disease groups. In 2011, sexually transmitted infections had 11 093 notifications attributed to remoteness and 5597 notifications attributable to socioeconomic disadvantage. Notification incidence was higher in Indigenous than in non-Indigenous Australians (aRR 5·3).

INTERPRETATION

All diseases had differing geographical concentration and sociodemographic risk. Overall, sociodemographic inequities in infectious disease notifications have decreased, but remain unacceptably high. National communicable disease control is complex, requiring both targeted and population-wide interventions.

FUNDING

None.

Determinants of Chlamydia, Gonorrhea, and Coinfection in Heterosexual Adolescents Attending the National Public Sexually Transmitted Infection Clinic in Singapore

BACKGROUND

Amidst recent trends in rising rates of chlamydia and gonorrhea among Singaporean adolescents, there are limited data on risk factors associated with these infections that may inform prevention strategies in this population.

METHODS

A cross-sectional study of chlamydia and gonorrhea positivity was conducted among 1458 sexually active heterosexual adolescents between 14 and 19 years old attending the national public sexually transmitted infection clinic from 2006 to 2013. The association with demographic and behavioral characteristics was assessed by crude prevalence ratio, and negative binomial regression modeling was used to obtain adjusted prevalence ratios (aPRs).

RESULTS

Chlamydia positivity was found in 23.6% of males and 36.6% of females, gonorrhea positivity in 33.1% of males and 15.9% of adolescent girl, and coinfection positivity in 10.2% of males and 10.1% of females. In multivariable analysis, chlamydia was positively associated with being Malay (aPR, 1.6; 95% confidence interval [CI], 1.1-2.1) and inconsistent condom use for vaginal sex (aPR, 6.5; 95% CI = 2.4-17.4) in males and with being Malay (aPR, 1.9; 95% CI = 1.5-2.4), inconsistent condom use for vaginal sex (aPR, 2.0; 95% CI = 1.1-3.9), and number of lifetime partners in females (aPR, 1.1; 95% CI = 1.0-1.1). Gonorrhea was positively associated with being Malay (aPR, 3.2; 95% CI = 2.4-4.4), inconsistent condom use for vaginal sex (aPR, 5.4; 95% CI = 2.1-14.4), and number of lifetime partners (aPR, 1.1; 95% CI = 1.0-1.1) in males and with being Malay (aPR, 3.7; 95% CI = 2.4-5.7) in females. Malays had a higher proportion of sexual risk behaviors compared with the non-Malays.

CONCLUSIONS

Ethnicity and high-risk sexual behaviors are important determinants of chlamydia, gonorrhea, and coinfection for adolescents attending this clinic. Targeted interventions are needed to lower the prevalence of high-risk sexual behaviors for the Malay adolescents in this clinic.

Which sexually active female students get themselves tested for Chlamydia trachomatis? A cohort study

Using data from the Prevention of Pelvic Infection (POPI) chlamydia screening trial, we compared the characteristics of female students who did or did not get tested for chlamydia outside the trial during 12 months' follow-up. Of the 2529 women in the trial, we excluded 68 chlamydia positives in the intervention group who were referred for treatment at baseline. Of the remaining 2461 women, 1980 (80%) answered the question about testing during follow-up on their 12 months' questionnaire and were included in the cohort. Of 1980 respondents, 529 (27%) reported having an independent chlamydia test, including 30 (48%) of 63 women with undiagnosed chlamydia at baseline. Predictors of testing included having undiagnosed chlamydia at baseline (adjusted odds ratio 2.44; 95% confidence interval 1.39-4.28), ≥2 sexual partners in the year prior to baseline (OR 1.99; 95% CI 1.60-2.48), history of sexually transmitted infection (1.63: 1.20-2.22); symptoms of pelvic discomfort, dyspareunia, abnormal vaginal discharge or inter-menstrual bleeding (1.38; 1.09-1.73); and black ethnicity (1.37, 1.06-1.76). Although more women with risk factors got tested, half of women with undiagnosed chlamydia did not get tested. To optimise detection of chlamydia, testing should be offered routinely.

Cervico-vaginal immunoglobulin G levels increase post-ovulation independently of neutrophils

The prevalence of sexually transmitted infections (STIs) is often higher in females than in males. Although the reproductive cycle profoundly modulates local immunity in the female reproductive tract (FRT) system, significant gaps in our knowledge of the immunobiology of the FRT still exist. An intriguing and frequently observed characteristic of the FRT is the predominant presence of immunoglobulin (Ig) G in cervico-vaginal secretions. We show here that in the mouse, IgG accumulation was enhanced approximately 5-fold post-ovulation, and was accompanied by an influx of neutrophils into the FRT. To determine whether these two events were causally related, we performed short-term neutrophil depletion experiments at individual stages throughout the estrous cycle. Our results demonstrate that neutrophils were not necessary for cycle-dependent tissue remodeling and cycle progression and that cycle-dependent IgG accumulation occurred independent of neutrophils. We thus conclude that neutrophil influx and IgG accumulation are independent events that occur in the FRT during the reproductive cycle.

Frequency and correlates of culture-positive infection with Neisseria gonorrhoeae in England: a review of sentinel surveillance data

OBJECTIVES

Reference laboratories are increasingly using more sensitive rapid molecular techniques, such as nucleic acid amplification tests (NAATs), to diagnose infections with Neisseria gonorrhoeae. We determined the proportion of patients at sentinel genitourinary medicine clinics in England whose NAAT-positive diagnoses were also culture-positive for N. gonorrhoeae, and investigated whether they differed from those that were not.

METHODS

Behavioural and clinical data from all NAAT-positive patients reported from 23 clinics included in the Gonoccocal Resistance to Antimicrobials Surveillance Programme from July to September 2012 were included in this analysis. Unadjusted and adjusted associations between patient characteristics and culture-positive infection with N. gonorrhoeae were determined.

RESULTS

Of 3076 NAAT-positive patients, 46.4% had culture-positive infections. Most NAAT-positive patients were <35 years old (73.0%), white (67.9%), and men who had sex with men (60.1%). Women and men who had sex with men were less likely than heterosexual men to have culture-positive infections (adjusted OR (95% CI) 0.53 (0.41 to 0.68), p<0.001; and 0.74 (0.59 to 0.93), p=0.010, respectively), while those who were symptomatic (4.61 (3.92 to 5.42), p<0.001), and those presenting with infection at multiple sites (2.15 (1.76 to 2.62), p<0.001) were more likely to have culture-positive infections.

CONCLUSIONS

Although gonococcal isolates were available from almost half of the NAAT-positive patients, culture was not attempted or may have failed in the remainder. Patients with culture-positive isolates were not representative of all NAAT-positive patients. Routine culture is necessary for monitoring emerging antimicrobial resistance and to inform gonorrhoea treatment guidelines.

Care Seeking Behaviour and Barriers to Accessing Services for Sexual Health Problems among Women in Rural Areas of Tamilnadu State in India

Background. Sexually transmitted infections (STIs) may be either asymptomatic or symptomatic. Regardless of the presence or absence of symptoms all STIs can lead to major complications if left untreated. Objective. To assess the care seeking behaviour and barriers to accessing services for sexual health problems among young married women in rural areas of Thiruvarur district of Tamil Nadu state in India. Methods. A community based cross-sectional study was conducted in 28 villages selected using multistage sampling technique for selecting 605 women in the age group of 15–24 years during July 2010–April 2011. Results. The prevalence rate of reproductive tract infections (RTIs) and STIs was observed to be 14.5% and 8.8%, respectively, among the study population. Itching/irritation over vulva, thick white discharge, discharge with unpleasant odor, and frequent and uncomfortable urination were most commonly experienced symptoms of sexual health problems. Around three-fourth of the women received treatment for sexual health problems. Perception of symptoms as normal, feeling shy, lack of female health workers, distance to health facility, and lack of availability of treatment were identified as major barriers for not seeking treatment for RTIs/STIs. Conclusion. Family tradition and poor socioeconomic conditions of the family appear to be the main reasons for not utilizing the health facility for sexual health problems. Integrated approach is strongly suggested for creating awareness to control the spread of sexual health problems among young people.

Inequalities in the incidence of infectious disease in the North East of England: a population-based study

The objective of this study was to measure the association between deprivation and incidence of 21 infectious diseases in the North East of England (2007–2011). We used count regression models with the Index of Multiple Deprivation and population/landscape data for small areas (~1500 persons). Deprivation significantly predicted incidence (P < 0·05) for 17 infectious diseases. The direction of association was broadly consistent within groups: increased incidence with increased deprivation for all three bloodborne viruses, 2/3 invasive bacterial diseases, 4/5 sexually transmitted infections (STI) and tuberculosis (TB); decreased incidence with increased deprivation for 5/6 infectious intestinal diseases (IID) and 2/3 vaccine-preventable diseases. Associations were removed for all but one IID (E. coliO157 infection) after accounting for recent foreign travel. Hepatitis C virus, TB and STI are priority infections for reduction of inequalities associated with deprivation in the North East of England.

The spatial and temporal association of neighborhood drug markets and rates of sexually transmitted infections in an urban setting

This study examined temporal and spatial relationships between neighborhood drug markets and gonorrhea among census block groups from 2002 to 2005. This was a spatial, longitudinal ecologic study. Poisson regression was used with adjustment in final models for socioeconomic status, residential stability and vacant housing. Increased drug market arrests were significantly associated with a 11% increase gonorrhea (adjusted relative risk (ARR) 1.11; 95% CI 1.05, 1.16). Increased drug market arrests in adjacent neighborhoods were significantly associated with a 27% increase in gonorrhea (ARR 1.27; 95% CI 1.16, 1.36), independent of focal neighborhood drug markets. Increased drug market arrests in the previous year in focal neighborhoods were not associated with gonorrhea (ARR 1.04; 95% CI 0.98, 1.10), adjusting for focal and adjacent drug markets. While the temporal was not supported, our findings support an associative link between drug markets and gonorrhea. The findings suggest that drug markets and their associated sexual networks may extend beyond local neighborhood boundaries indicating the importance of including spatial lags in regression models investigating these associations.

Global burden of human papillomavirus and related diseases

The worldwide prevalence of infection with human papillomavirus (HPV) in women without cervical abnormalities is 11-12% with higher rates in sub-Saharan Africa (24%), Eastern Europe (21%) and Latin America (16%). The two most prevalent types are HPV16 (3.2%) and HPV18 (1.4%). Prevalence increases in women with cervical pathology in proportion to the severity of the lesion reaching around 90% in women with grade 3 cervical intraepithelial neoplasia and invasive cancer. HPV infection has been identified as a definite human carcinogen for six types of cancer: cervix, penis, vulva, vagina, anus and oropharynx (including the base of the tongue and tonsils). Estimates of the incidence of these cancers for 2008 due to HPV infection have been calculated globally. Of the estimated 12.7 million cancers occurring in 2008, 610,000 (Population Attributable Fraction [PAF]=4.8%) could be attributed to HPV infection. The PAF varies substantially by geographic region and level of development, increasing to 6.9% in less developed regions of the world, 14.2% in sub-Saharan Africa and 15.5% in India, compared with 2.1% in more developed regions, 1.6% in Northern America and 1.2% in Australia/New Zealand. Cervical cancer, for which the PAF is estimated to be 100%, accounted for 530,000 (86.9%) of the HPV attributable cases with the other five cancer types accounting for the residual 80,000 cancers. Cervical cancer is the third most common female malignancy and shows a strong association with level of development, rates being at least four-fold higher in countries defined within the low ranking of the Human Development Index (HDI) compared with those in the very high category. Similar disparities are evident for 5-year survival-less than 20% in low HDI countries and more than 65% in very high countries. There are five-fold or greater differences in incidence between world regions. In those countries for which reliable temporal data are available, incidence rates appear to be consistently declining by approximately 2% per annum. There is, however, a lack of information from low HDI countries where screening is less likely to have been successfully implemented. Estimates of the projected incidence of cervical cancer in 2030, based solely on demographic factors, indicate a 2% increase in the global burden of cervical cancer, i.e., in balance with the current rate of decline. Due to the relative small numbers involved, it is difficult to discern temporal trends for the other cancers associated with HPV infection. Genital warts represent a sexually transmitted benign condition caused by HPV infection, especially HPV6 and HPV11. Reliable surveillance figures are difficult to obtain but data from developed countries indicate an annual incidence of 0.1 to 0.2% with a peak occurring at teenage and young adult ages. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Risk factors for and prevention of human papillomaviruses (HPV), genital warts and cervical cancer

Genital HPV infection is associated with development of cervical cancer, cervical neoplasia, anogenital warts, and other anogenital cancers. A number of reviews have primarily addressed the role of HPV infection in cervical carcinogenesis, and differences in human papillomavirus (HPV) subtypes found in cervical cancer cases by histology and geographical region. This review provides an informative summary of the broad body of literature on the burden of HPV, the risk factors for HPV infection, genital warts and cervical cancer, and preventive measures against these conditions in females. Studies have identified the main risk factors for genital HPV infection in females as follows: acquisition of new male partners; an increasing number of lifetime sexual partners both in females and their male partners; and having non-monogamous male partners. Cervical cancer screening and HPV vaccination are the primary measures currently recommended to prevent cervical cancer. There is also an ongoing debate and conflicting findings on whether male circumcision and condom use protect against HPV infection and subsequent development of HPV-related illnesses in females.

The importance of distinguishing between black Caribbeans and Africans in understanding sexual risk and care-seeking behaviours for sexually transmitted infections: evidence from a large survey of people attending genitourinary medicine clinics in England

BACKGROUND

In the UK, black Caribbean and African populations experience disproportionately high rates of sexually transmitted infections (STIs) and HIV. Often studies do not differentiate between these populations notwithstanding differences in STI epidemiology and sociodemographics.

METHODS

Patterns of care-seeking behaviour for STIs were explored separately for black Caribbean (n = 345), black African (n = 193) and white people through a cross-sectional survey of 2824 people attending five genitourinary medicine (GUM) clinics in England.

RESULTS

Black Caribbean men were least likely to use, or try to use, their general practice surgery prior to GUM clinic attendance (16.6%). Symptomatic black Caribbean and African men were least likely to delay seeking care (30.8 and 26.3%, respectively). Symptomatic black Caribbean men faced the least provider delay in accessing care (27.3%). Black Caribbean men and women were most likely, and black African men and women least likely, to be diagnosed with an STI (49.7 and 32.0% versus 26.8 and 16.3%, respectively). Among symptomatic women, black Caribbeans and, among symptomatic men, black Africans were most likely to report abstaining from sex (46.3 and 73.1%, respectively).

CONCLUSIONS

Our analyses highlight the importance of distinguishing between black ethnic groups and the need for future studies to ensure sufficiently large samples to permit such analyses.

Diagnosis of Chlamydia infection in women

OBJECTS

Chlamydia (Chlamydia trachomatis) is a common sexually transmitted infection that places a heavy burden on women and neonatal health. To avoid severe sequelae such as female infertility, ectopic pregnancy, neonatal infection, such as ophthalmitis, and chronic pelvic pain prompt and appropriate antibiotic treatment seems the best policy in treating this group of patients. However, adequate treatment is not easy because many factors can interfere with an early and rapid identification of Chlamydia infection, including complicated mixed microflora of the vagina and cervix, a nonuser-friendly detection system, and the time required for identification, even with the combination of specific complaints and a high level of clinical alertness. When dealing with a female patient in a point-of-care (POC) clinic, we need to find the best strategy to provide the most efficient way to detect this infection.

MATERIALS AND METHODS

Totally five traditional methods and advanced technologies used for the diagnosis of Chlamydia infection in women were reviewed. A criterion proposed by World Health Organization with an acronym of ASSURED, representing affordable price, high sensitivity, high specificity, user-friendly design, rapid process, minimal equipment, and delivered-or-not, was used to reexamine these tools if they are the best tools. A multiplexed microchip-based immunoassay was evaluated as a potential tool. The ASSURED score was compared and a Chi-square test with a p value less than 0.05 was considered significant.

RESULTS

Traditional methods, such as symptoms approach, microscopic examination, and microorganism culture that have been broadly used once, are affordable, simple, and equipment-free but their relatively low sensitivity and specificity limit their use as a test of POC setting for these infected women. On the other hand, advanced technologies, such as antigen detection by immunoassay and nucleic acid amplification tests, have contributed to major progress in the diagnosis of Chlamydia because of its accuracy, convenience, and time saving. However, nucleic acid amplification tests are too expensive, so they cannot be accepted as a screening tool in a developing country. The only significant finding with p value less than 0.01 was achieved when a more sensitive immunoassay system developed successfully as a test of POC setting.

CONCLUSIONS

Eventually, advances in laboratory techniques will satisfy our needs to detect Chlamydia infection economically and instantly. Microarray chips might be a relatively rapid, easy, inexpensive, and sensitive tool to detect many pathogens, including Chlamydia, using a one-time vaginal sampling process, which might make a POC policy possible.

Will chlamydia screening reach young people in deprived areas in England? Baseline analysis of the English National Chlamydia Screening Programme delivery in 2008

BACKGROUND

The National Chlamydia Screening Programme (NCSP) was established in England to control chlamydia in people <25 years. This study examined variations in NCSP delivery in 2008, its first full year of national coverage, by comparing the distribution of screening venues and coverage with the risk of testing positive in men and women by socioeconomic circumstances (SEC) and age.

METHODS

A total of 550,000 NCSP screening records from 2008 were linked to the Index of Multiple Deprivation 2007. NCSP provision (venues/1000 population aged 13-24 years) was examined by SEC. NCSP coverage (tests/target population) and chlamydial positivity (positive results/[positive + negative results]) were examined separately in men and women by SEC and age. Odds ratios for positivity were calculated, adjusted for socioeconomic quintile, age, ethnicity, behavior, and screening provider.

RESULTS

NCSP coverage was just 4.1% (95% confidence interval [CI]: 4.0-4.1) in men and 9.6% (95% CI: 9.5-9.6) in women. Screening provision and coverage were highest in more socioeconomically deprived areas where chlamydia positivity was also highest. The adjusted odds for testing positive in the most deprived areas was 1.4 (95% CI: 1.3-1.5) times higher in men and 1.4 (95% CI: 1.4-1.5) times higher in women than the least deprived areas.

CONCLUSIONS

In the first year in which all areas delivered screening, the NCSP's total coverage was low, particularly in men. However, coverage was higher in deprived populations, who were also at increased risk of testing positive for infection. This analysis provides a baseline by which to monitor social variations in NCSP delivery as coverage expands.

Incorporating geospatial capacity within clinical data systems to address social determinants of health

Linking electronic health record (EHR) systems with community information systems (CIS) holds great promise for addressing inequities in social determinants of health (SDH). While EHRs are rich in location-specific data that allow us to uncover geographic inequities in health outcomes, CIS are rich in data that allow us to describe community-level characteristics relating to health. When meaningfully integrated, these data systems enable clinicians, researchers, and public health professionals to actively address the social etiologies of health disparities.This article describes a process for exploring SDH by geocoding and integrating EHR data with a comprehensive CIS covering a large metropolitan area. Because the systems were initially designed for different purposes and had different teams of experts involved in their development, integrating them presents challenges that require multidisciplinary expertise in informatics, geography, public health, and medicine. We identify these challenges and the means of addressing them and discuss the significance of the project as a model for similar projects.

Transmission of Chlamydia trachomatis through sexual partnerships: a comparison between three individual-based models and empirical data

Chlamydia trachomatis is the most common bacterial sexually transmitted infection (STI) in many developed countries. The highest prevalence rates are found among young adults who have frequent partner change rates. Three published individual-based models have incorporated a detailed description of age-specific sexual behaviour in order to quantify the transmission of C. trachomatis in the population and to assess the impact of screening interventions. Owing to varying assumptions about sexual partnership formation and dissolution and the great uncertainty about critical parameters, such models show conflicting results about the impact of preventive interventions. Here, we perform a detailed evaluation of these models by comparing the partnership formation and dissolution dynamics with data from Natsal 2000, a population-based probability sample survey of sexual attitudes and lifestyles in Britain. The data also allow us to describe the dispersion of C. trachomatis infections as a function of sexual behaviour, using the Gini coefficient. We suggest that the Gini coefficient is a useful measure for calibrating infectious disease models that include risk structure and highlight the need to estimate this measure for other STIs.

Population levels of psychological stress, herpesvirus reactivation and HIV

Nearly 40,000 Americans are newly infected with Human Immunodeficiency Virus (HIV) each year. Recently, studies have demonstrated associations between group-level characteristics and the prevalence and incidence of HIV/Acquired Immune Deficiency Syndrome (AIDS) and other sexually transmitted diseases. Two mechanisms previously posited to explain these associations are neighborhood effects on risk behaviors and social or institutional policies. In this paper, we hypothesize that adversity at the population level, such as neighborhood poverty, also influences HIV risk through stress-mediated aberrations in immunological susceptibility by reviewing existing data examining each of these pathways. In particular, we review the evidence showing that: (1) Neighborhood ecologic stressors influence neighborhood- and individual-levels of mental health, psychosocial stress, and HIV/AIDS risk, (2) Individual-level psychosocial stressors influence progression from HIV to AIDS through stress-related hormonal changes, and (3) Individual-level psychosocial stressors influence HIV acquisition via stress-related reactivation of latent herpesviruses, specifically EBV and HSV-2. Our review indicates that further studies are needed to examine the joint pathways linking neighborhood-level sources of psychosocial stress, stress-related reactivation of HSV-2 and EBV, and increased acquisition rates of HIV. We suggest using a multi-level framework for targeting HIV prevention efforts that address not only behavioral risk factors, but structural, political, and institutional factors associated with neighborhood disadvantage, levels of psychosocial stress, and prevention or treatment of HSV-2 and EBV.

Upstairs and downstairs: socio-economic and gender interactions in herpes simplex virus type 2 seroprevalence in australia

BACKGROUND

This study investigates socio-economic differentials in herpes simplex virus type 2 (HSV-2) seroprevalence in Australian men and women using individual and geographic measures of socio-economic status.

METHODS

HSV-2 seropositivity among men and women aged over 25 years was investigated by levels of individual and area-based measures of socio-economic status (SES) in a series of Poisson regression models, variously adjusting for age, country of birth, marital status, indigenous status, and urban/rural residence as potential confounders. Serum and socio-demographics were collected during 1999 and 2000 in a population-based Australia-wide prevalence survey.

RESULTS

HSV-2 seroprevalence was significantly lower in areas of low SES than in high SES areas among both men (P for trend <0.001) and women (P for trend = 0.004) for all ages. A similar pattern was evident for individual education level for men with lower rates of HSV-2 in respondents with lower educational achievement (relative risk = 0.77, 95% CI 0.61-0.97, P = 0.024). In contrast, HSV-2 prevalence was higher for women with lower individual levels of education for all ages (relative risk = 1.22, 95% CI 1.04-1.44, P = 0.017). Analyses stratifying HSV-2 prevalence for individual education level by area-based SES showed the highest prevalence of HSV-2 in women with the lowest education level residing in the highest SES areas. This pattern was not evident in men, with a greater concordance between individual and area-based SES.

CONCLUSION

HSV-2 seroprevalence is not consistently distributed across individual and area measures of SES, suggesting that upward and downward mixing between social strata in men and women is an important mode of HSV-2 transmission.

The seroprevalence of human papillomavirus by immune status and by ethnicity in London

Background

The natural history of cutaneous HPV is unclear and in particular, seroprevalence among individuals with different levels of immune function and ethnicity is unknown. As part of a study of cutaneous squamous cell carcinoma (SCC) and HPV among organ transplant recipients (OTR) from London, we investigated the seroprevalence and risk factors for 34 HPV types (detected using Luminex technology) among 409 OTR patients without skin cancer (243 Caucasians and 166 non-Caucasians), 367 individuals with end stage renal failure on dialysis (222 Caucasians and 145 non-Caucasians) and 152 immunocompetent (IC) individuals without skin cancer (102 Caucasians and 50 non-Caucasians) to compare the HPV seroprevalence in patients with differing immune status and ethnicity. In total, seroprevalence data from 928 individuals, all from London, was available.

Results

Overall, no difference between HPV seroprevalence by immune status was observed (P = 0.3) among Caucasian or among non-Caucasian individuals, with seroprevalence varying from 87% to 94% across different immune status and ethnic groups. Those individuals seropositive to multiple types of one genus were more likely to be seroreactive to multiple types of another genus, independent of immune status or ethnicity. Lower seroprevalence for gammaHPV 4, and to a lesser extent gammaHPV 48, were observed among OTR compared to IC and dialysis patients. Higher seroprevalence against antibodies to betaHPV 93 were detected more frequently in non-Caucasians than Caucasians whereas muHPV 1 and, to a lesser extent, gammaHPV 4 were found more frequently among Caucasians - these findings were independent of immune status. Within non-Caucasian subgroups, the seroprevalence of 8 HPV (alpha-mucosal HPV16 and 13, alpha-cutaneous HPV7 and 2, betaHPV8, 17, 23 and 38) was significantly (P < 0.02) higher in Black compared to Asian patients. HPV16 being sexually transmitted, this might suggest a potential sexual route of transmission for some beta HPV types.

Conclusion

We did not observe major disturbance in antibody response between immunocompetent, dialysis and OTR individuals, but significant differences in HPV seroprevalence were identified according to ethnicity. Further research is needed to clarify the natural history of cutaneous HPV, particularly given the growing research interest in its possible role in the pathogenesis of cutaneous SCC.

A metapopulation modelling framework for gonorrhoea and other sexually transmitted infections in heterosexual populations

Gonorrhoea continues to be a public health problem in the UK, and is the second most common bacterial sexually transmitted infection (STI) after chlamydia. In the UK, gonorrhoea is disproportionately concentrated in epidemiologically distinct subpopulations, with much higher incidence rates in young people, some ethnic minorities and inner city subpopulations. The original model of STI transmission proposed by Hethcote and Yorke explained some of these features through the concept of the 'core group'. Since then, several authors have modified the original model approach to include multiple sexual activity classes, but found this modelling approach to be inadequate when applied to low-prevalence settings such as the UK. We present a metapopulation framework for modelling gonorrhoea and other STIs. The model proposes that the epidemiology of gonorrhoea is largely driven by subpopulations with higher than average concentrations of individuals with high sexual risk activity. We show how this conceptualization of gonococcal epidemiology overcomes key limitations associated with some of the prior efforts to model gonorrhoea. We also use the model to explain several epidemiological features of gonorrhoea, such as its asymmetric distribution across subpopulations, and the contextual risk experienced by members of at-risk subpopulations. Finally, we extend the model to explain the distribution of other STIs, using chlamydia as an example of a more ubiquitous bacterial STI.

Spatial pattern of HIV-1 mother-to-child-transmission in Madrid (Spain) from 1980 till now: demographic and socioeconomic factors

OBJECTIVE

To evaluate any possible association between indicators of social inequalities and the geographical distribution of HIV-1 mother-to-child transmission (MTCT) cases in Madrid.

METHODS

We carried out an observational survey of 224 HIV-1 vertically infected children born in 1980-2006 living in Madrid. We elaborated maps representing the prevalence of HIV-1 MTCT cases. We assessed the association between indicators of social inequalities and the spatial distribution of MTCT cases. Poisson univariate and multivariate analysis of risk factors for MTCT were performed.

RESULTS

We identified core areas of transmission mainly in southern Madrid until 2006. The prevalence of MTCT cases was significantly correlated to the percentage of immigrants, illiterates, unemployed women and the income in 1996 and 2000/2001. The risk of MTCT increased in the periods up to 1996 compared with the calendar period 1980-1989, whereas the risk decreased in 1999-2006 [relative risk, 0.08; 95% confidence interval (CI), 0.03-0.18; P < 0.001]. The risk was especially high in the districts of Usera (absolute relative risk, 11.4; 95% CI, 2.6-49.5; P = 0.001), Puente de Vallecas (absolute relative risk, 14.0; 95% CI, 3.4-57.9; P < 0.001) and San Blas (absolute relative risk, 12.5; 95% CI, 2.9-53.6; P = 0.001). The percentage of illiterates was the indicator that explained the risk of MTCT (absolute relative risk, 1.07; 95% CI, 1.05-1.10; P = 0.001).

CONCLUSION

We observed a geographic heterogeneity of the HIV-1 vertical transmission with the highest prevalence in disadvantaged districts. What is described in the present review is the HIV-1 vertical transmission within a social context; this approach could be relevant in analysing the pattern of HIV-1 transmission in other Western cities or highlighting the distribution of other infectious diseases.

Geographical and demographic clustering of gonorrhoea in London

BACKGROUND

Gonorrhoea is an important cause of sexual ill health and is concentrated in geographical areas and demographic groups. This study explores the distribution of gonorrhoea across London.

METHODS

Epidemiological data on all gonorrhoea cases were collected from 13 major genitourinary clinics in London between 1 June and 30 November 2004. Samples were stored centrally and typed using NG-MAST. The postcode of each case's main residence was used to calculate incidence of gonorrhoea by borough using data from the UK 2001 census and a population survey on residence of men who have sex with men (MSM).

RESULTS

2,891 cases were confirmed, 1,822 of which had postcode data, resided in London, and had their strain successfully typed. There was a very high incidence of gonorrhoea in MSM (1,834 per 100,000 population) and heterosexuals of black ethnicity (392 per 100,000). The incidence among heterosexuals was highest in City of London (390 per 100,000, 95% CI 213 to 566), Southwark (308 per 100,000, 95% CI 280 to 336), Hackney (284 per 100,000, 95% CI 254 to 313), and Lambeth (216 per 100,000, 95% CI 194 to 239) and was not associated with measures of social deprivation (correlation coefficient = 0.0008, p = 0.97) but was strongly associated with black ethnicity (correlation coefficient = 0.48, p = 0.01). 45% of cases had one of the 21 major strains; eight of these strains were significantly clustered geographically and persisted for a shorter duration than those that were not clustered. Patients travelled a mean of 7.7 km from their home to the clinic.

CONCLUSIONS

High gonorrhoea incidence in London is observed in MSM and heterosexuals of black ethnicity. Endemic strains in both MSM and heterosexuals are diagnosed at multiple clinics. Interventions, including partner notification, must therefore operate between clinics.

Social capital and rates of gonorrhea and syphilis in the United States: Spatial regression analyses of state-level associations

We conducted spatial regression analysis to account for spatial clustering of sexually transmitted diseases (STDs) and to examine the state-level association between social capital (using Putnam's public use data set) and rates of gonorrhea and syphilis. We conducted the analysis for the 48 contiguous states of the United States for 1990, 1995, and 2000 and controlled for the effects of regional variation in STD rates, and for state variation in poverty, income inequality, racial composition, and percentage aged 15-34 years. We compared the results of the spatial regression analysis with those of ordinary least squares (OLS) regression. Controlling for all population-level variables, the percentage of variation explained by the OLS regression and by the spatial regression were similar (mid-90s for gonorrhea and low-70s for syphilis), the standardized parameter estimates were similar, and the spatial lag parameter was not statistically significant. Social capital was not associated with STD rates when state variation in racial composition was included in the regression analysis. In this analysis, states with a higher proportion of residents who were African-American had higher STD rates. When we did not control for racial composition, regression analysis showed that states with higher social capital had lower STD rates. We conjecture that sexual networks and sexual mixing drive the association between social capital and STD rates and highlight important measurement and research questions that need elucidation to understand fully the relationship between social capital and STDs.

Spatial bridges and the spread of Chlamydia: the case of a county in Sweden

OBJECTIVES

The so-called small-world effect can have a great impact on efforts to control the incidence and prevalence of sexually transmitted infections. This is because a small number of so-called spatial bridgers (individuals who, through sexual contacts, interconnect geographically distant areas) can drastically lower the average path length in the sexual network and, as a result, make locally based intervention programs much less effective. The objectives of this study were to analyze the sociodemographic characteristics of these bridgers and to compare the result with the remaining study population. The purpose was to determine whether it is possible to identify them for targeted intervention programs.

STUDY DESIGN

During 2001, contact tracing was performed in approximately 98% of all cases with positive test results in Värmland County. The sexual networks obtained constituted a study population of 851 individuals. Statistical analysis was used to characterize individuals engaged in spatial bridging behavior.

RESULTS

Approximately 8% of the study population was characterized as spatial bridgers. Using multivariate analysis, we found almost no significant differences between these individuals and the rest of the study population when it came to sociodemographic variables, including education, economy, and ethnicity.

CONCLUSION

The number of spatial bridgers is high enough to create a small-world network with links that can fuel the endemic chlamydia in Värmland County. Sociodemographic information could not be used to characterize spatial bridgers. In interventions against chlamydia, spatial bridgers shall be considered as potentially important for sustaining the disease.

Chapter 4: Burden and management of non-cancerous HPV-related conditions: HPV-6/11 disease

Human Papillomavirus (HPV)-6 and -11 are the causative agents of ano-genital warts (GWs) and recurrent respiratory papillomatosis (RRP). They are low-risk HPV types that are uncommonly found in malignant lesions. GWs are an extremely prevalent sexually transmitted disease, whereas RRP is a rare disease that can be life threatening and requires multiple surgical procedures. GWs and RRP cause substantial healthcare costs. A quadrivalent HPV-6/11/16/18 vaccine (Merck/SPMSD) has shown essentially 100% protection against GWs in women in early studies. Cost-effectiveness analyses are needed to assess the benefits of the HPV-6/11 virus-like particle (VLP) components of the quadrivalent vaccine in population-based vaccination programmes.