Previous history of gonococcal infection as a risk factor in patients presenting with gonorrhoea

Immune responses to Neisseria gonorrhoeae and implications for vaccine development

Neisseria gonorrheoae is the causative agent of gonorrhea, a sexually transmitted infection responsible for a major burden of disease with a high global prevalence. Protective immunity to infection is often not observed in humans, possible due to high variability of key antigens, induction of blocking antibodies, or a large number of infections being relatively superficial and not inducing a strong immune response. N. gonorrhoeae is a strictly human pathogen, however, studies using mouse models provide useful insights into the immune response to gonorrhea. In mice, N. gonorrhoea appears to avoid a protective Th1 response by inducing a less protective Th17 response. In mouse models, candidate vaccines which provoke a Th1 response can accelerate the clearance of gonococcus from the mouse female genital tract. Human studies indicate that natural infection often induces a limited immune response, with modest antibody responses, which may correlate with the clinical severity of gonococcal disease. Studies of cytokine responses to gonococcal infection in humans provide conflicting evidence as to whether infection induces an IL-17 response. However, there is evidence for limited induction of protective immunity from a study of female sex workers in Kenya. A controlled human infection model (CHIM) has been used to examine the immune response to gonococcal infection in male volunteers, but has not to date demonstrated protection against re-infection. Correlates of protection for gonorrhea are lacking, which has hampered the progress towards developing a successful vaccine. However, the finding that the Neisseria meningitidis serogroup B vaccines, elicit cross-protection against gonorrhea has invigorated the gonococcal vaccine field. More studies of infection in humans, either natural infection or CHIM studies, are needed to understand better gonococcal protective immunity.

Sexual exposure and sexual behaviour in the interval between gonorrhoea treatment and test of cure: a cross-sectional cohort study

OBJECTIVES

We explored sexual contact in the interval between the treatment for gonorrhoea and attending for a test of cure (ToC) and identified factors associated with sexual contact in this period.

METHODS

Multivariable analysis of demographic, behavioural and clinical data with self-reported sexual contact prior to attending for a gonorrhoea ToC evaluation among participants recruited into the 'Gentamicin for the Treatment of Gonorrhoea' trial in England, between October 2014 and November 2016. Associations with sexual contact were expressed as prevalence ratios (PR) and their corresponding 95% CI.

RESULTS

The median time to ToC was 15 days (interquartile range 14-20 days). 197/540 (37%) participants reported sexual contact in the time between treatment and ToC. Of these, 173/197 (88%) participants reported inconsistent condom use, including with previous partners (133/197 (68%)). A history of gonorrhoea (adjusted PR (aPR) 1.32 (1.03 to 1.69)) or syphilis (aPR 1.19 (1.08 to 1.32)), being in regular (aPR 1.71 (1.41 to 2.09)) sexual relationships, high number of partners in the last 3 months (aPR 1.77 (1.25 to 2.51))-'more than 5 partners' vs '0 to 1 partner', and attending for a ToC more than 14 days after treatment (aPR 1.40 (1.08 to 1. 81)) were associated with reporting sexual contact before the ToC appointment. However, age (aPR (1.00 (0.99 to 1.01)) and presenting with specific symptoms at baseline (aPR 1.17 (0.95 to 1.44)) were not associated with sexual contact by the ToC attendance.

CONCLUSION

Sexual activity after receiving treatment for gonorrhoea and prior to a ToC evaluation was common. This was associated with previous infection history and specific behavioural characteristics. Knowledge of these factors can help guide safe sex counselling at the time of treatment.

Global epidemiology of Neisseria gonorrhoeae in infertile populations: systematic review, meta-analysis and metaregression

Objective

To provide an in-depth systematic assessment of the global epidemiology of gonorrhoea infection in infertile populations.

Methods

A systematic literature review was conducted up to 29 April 2019 on international databases and WHO regional databases, and reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All prevalence measures of gonorrhoea infection among infertile populations, based on primary data, qualified for inclusion. Infertile populations were broadly defined to encompass women/men undergoing infertility evaluation or treatment (infertility clinic attendees and partners). Pooled mean prevalence by relevant strata was estimated using random-effects meta-analysis. Associations with prevalence and sources of heterogeneity were explored using metaregression. Risk of bias was assessed using four quality domains.

Findings

A total of 147 gonorrhoea prevalence studies were identified from 56 countries. The pooled mean prevalence of current gonorrhoea infection was estimated globally at 2.2% (95% CI 1.3% to 3.2%), with the highest prevalence in Africa at 5.0% (95% CI 1.9% to 9.3%). The mean prevalence was higher for populations with tubal factor infertility (3.6%, 95% CI 0.9%–7.7%) and mixed cause and unexplained infertility (3.6%, 95% CI 0.0% to 11.6%) compared with other diagnoses, such as ovarian and non-tubal infertility (0.1%, 95% CI 0.0% to 0.8%), and for secondary (2.5%, 95% CI 0.2% to 6.5%) compared with primary (0.5%, 95% CI 0.0% to 1.7%) infertility. Metaregression identified evidence of variations in prevalence by region and by infertility diagnosis, higher prevalence in women than men and a small-study effect. There was a trend of declining prevalence by about 3% per year over the last four decades (OR=0.97, 95% CI 0.95 to 0.99).

Conclusions

Gonorrhoea prevalence in infertile populations is several folds higher than that in the general population, with even higher prevalence in women with tubal factor infertility and in individuals with secondary infertility. These findings support the potential role of gonorrhoea in infertility and suggest that some infertility is possibly preventable by controlling gonorrhoea transmission.

PROSPERO registration number

CRD42018102934.

Global epidemiology of Neisseria gonorrhoeae in infertile populations: protocol for a systematic review

INTRODUCTION

A key target of the WHO's 'Global Health Sector Strategy on sexually transmitted infections, 2016-2021' is achieving 90% reduction in Neisseria gonorrhoeae (gonorrhoea for short) incidence globally by 2030. Though untreated, gonorrhoea has been linked to infertility, the epidemiology of this infection in infertile populations remains poorly understood and somewhat a neglected area of reproductive health. Our proposed systematic review aims to fill this gap by characterising comprehensively gonorrhoea infection in infertile populations globally.

METHODS AND ANALYSIS

All available studies of gonorrhoea infection in infertile populations, including infertility clinic attendees, will be systematically reviewed informed by Cochrane Collaboration guidelines. Findings will be reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data sources will be searched using broad index terms exploded to cover all subheadings and free text terms with no language or year restriction. Any epidemiological measure in infertile populations based on primary data will be eligible for inclusion. Measures based on different assay types will be extracted as separate studies for different analyses. Only one biospecimen type per assay type will be considered based on a predefined priority order. Samples including fewer than 10 participants or assessing infection in the upper genital tract will be excluded. Quality assessments will be conducted for all measures included in the review. Meta-analyses will be implemented using DerSimonian-Laird random effect models to estimate the mean prevalence of gonorrhoea in infertile populations globally, and stratified by WHO region, assay type, sex, infertility type, infertility diagnosis, among other factors. Detailed heterogeneity assessment will be performed, and potential sources of between-study heterogeneity will be explored using meta-regression. Review will be conducted from 26 March 2018 to 28 July 2019.

ETHICS AND DISSEMINATION

An institutional review board clearance is not required as all data are publicly available. The findings will be disseminated through a peer-reviewed publication and international scientific meetings/workshops with key stakeholders.

PROSPERO REGISTRATION NUMBER

CRD42018102934.

Is gonococcal disease preventable? The importance of understanding immunity and pathogenesis in vaccine development

Gonorrhea is a major, global public health problem for which there is no vaccine. The continuing emergence of antibiotic-resistant strains raises concerns that untreatable Neisseria gonorrhoeae may become widespread in the near future. Consequently, there is an urgent need for increased efforts towards the development of new anti-gonococcal therapeutics and vaccines, as well as suitable models for potential pre-clinical vaccine trials. Several current issues regarding gonorrhea are discussed herein, including the global burden of disease, the emergence of antibiotic-resistance, the status of vaccine development and, in particular, a focus on the model systems available to evaluate drug and vaccine candidates. Finally, alternative approaches to evaluate vaccine candidates are presented. Such approaches may provide valuable insights into the protective mechanisms, and correlates of protection, required to prevent gonococcal transmission, local infection and disease sequelae.

Detecting re-infection in patients after an initial diagnosis of gonorrhoea: is routine recall for re-screening useful?

To assess the outcome of routine sexually transmitted infection re-screening after a three-month interval in unselected patients diagnosed with gonorrhoea, we sought to assess whether this active approach would result in an increase in the number of people attending clinic and subsequently diagnosed with gonorrhoea re-infection, compared with normal re-presentation rates. A recall group of patients were invited for re-screening three months after their initial diagnosis of gonorrhoea. Permission was sought to send a reminder two weeks prior to their scheduled recall appointment. Comparisons were made with a historical control group of patients with gonorrhoea in the absence of any formal recall. Of the 242 patients in the intervention arm, 96 (40%) re-attended within six months, and 15 (6%) tested gonorrhoea positive. Two hundred and two patients were assessed in the control group, of whom 45 (22%) re-attended within six months, and 13 (6%) tested gonorrhoea positive. Women were more likely than men to re-attend following active recall, but they were not at higher risk of re-attending while re-infected with gonorrhoea. Active recall following a gonorrhoea diagnosis significantly increases re-attendance rates for repeat screening but did not result in an increased number of subsequent gonorrhoea diagnoses.