Models for sexually transmitted infections

Priorities for sexually transmitted infection vaccine research and development: Results from a survey of global leaders and representatives

Vaccines against sexually transmitted infections (STIs) are one of the most cost-effective means for STIs control. Safe and highly efficacious vaccines against human papillomavirus (HPV) have been major advances in STI prevention and provide inspiration for development of new STI vaccines. This article provides updates on research and development of individual vaccines against HPV, herpes simplex virus, Chlamydia trachomatis, Neisseria gonorrhoeae and Treponema pallidum. Key words: Sexually transmitted diseases; Vaccines; HPV; Herpes simplex virus; Chlamydia trachomatis

Purpose of reviewThis review provides an update on the need, development status, and important next steps for advancing development of vaccines against sexually transmitted infections (STIs), including herpes simplex virus (HSV), Neisseria gonorrhoeae (gonorrhea), Chlamydia trachomatis (chlamydia), and Treponema pallidum (syphilis).Recent findingsGlobal estimates suggest that more than a million STIs are acquired every day, and many new and emerging challenges to STI control highlight the critical need for development of new STI vaccines. Several therapeutic HSV-2 vaccine candidates are in Phase I/II clinical trials, and one subunit vaccine has shown sustained reductions in genital lesions and viral shedding, providing hope that an effective HSV vaccine is on the horizon. The first vaccine candidate for genital chlamydia infection has entered Phase I trials, and several more are in the pipeline. Use of novel technological approaches will likely see viable vaccine candidates for gonorrhea and syphilis in the future. The global STI vaccine roadmap outlines key activities to further advance STI vaccine development.SummaryMajor progress is being made in addressing the large global unmet need for STI vaccines. With continued collaboration and support, these critically important vaccines for global sexual and reproductive health can become a reality.

AAUS guidelines 2021 revision sexually transmitted infection (STIs) diagnostic strategy for STI

Intersecting epidemics and educable moments: sexually transmitted disease risk assessment and screening in men who have sex with men.

Toward global prevention of sexually transmitted infections (STIs): The need for STI vaccines

Protecting their adolescents from harm: parental views on STI vaccination

From Control to Crisis: The Resurgence of Sexually Transmitted Diseases.

The objective of this study was to test the effect of a brief educational and counseling intervention on increasing the uptake of free testing for Chlamydia trachomatis (chlamydia) and Neisseria gonorrhea (gonorrhea) among young female emergency department (ED) patients. Women are particularly vulnerable to more serious consequences of these infections due to asymptomatic presentation. Increased testing is important to detect, treat, and halt the spread of these infections among asymptomatic women. This was a randomized controlled trial. Research assistants (RAs) approached female patients in two EDs. Eligible patients were between 18 and 35 years of age, who reported having sex with males, but were not attending the ED for either treatment of sexually transmitted infection (STI) or testing for possible STI exposure. Participants responded to survey questions about their lifetime and past 3-month substance use, number of recent sexual partners, condom use, and perception of risks for chlamydia and gonorrhea infections. Following the survey, the RAs randomized participants into study control or treatment arms. Each treatment arm participant received a brief educational/counseling intervention from the RA. The brief intervention focused on the woman's personal risks for chlamydia and gonorrhea and condoms attitudes and usage. As the primary outcome of this study, participants were offered free urine tests for chlamydia and gonorrhea infection postintervention or post-survey completion, depending on group assignment. A total of 171 women completed the baseline assessment and were offered chlamydia and gonorrhea testing. The mean (±SD) age was 26 (±4.76) years, 18% were Hispanic, and 12% were Spanish-speaking only. The brief intervention that was offered to increase these women's awareness of their STI risk did not result in increased acceptance of testing; 48% in the brief intervention group accepted testing (95% confidence interval [CI] = 32% to 64%) versus 36% in the control group (95% CI = 19% to 53%). In a multivariable logistic regression, only self-identifying as being Hispanic was associated with greater willingness to be tested. Of the asymptomatic women tested (n = 71), five tested positive for chlamydia. This represents a positivity rate of 7%. There were no positive test results for gonorrhea. Women who reported high-risk factors for STI, such as younger age (≤25 years), having sex in the past 90 days without using condoms, identified substance use, or previous STI, were not more likely to accept the offer of chlamydia and gonorrhea testing. The brief intervention used in this study did not increase the uptake of testing for chlamydia and gonorrhea infections in this sample, in comparison to receiving no intervention. Although Hispanic women were more likely to accept chlamydia and gonorrhea testing, it is concerning that those women who report STI risk factors were not more likely to accept the offer of chlamydia and gonorrhea testing. Future research should focus on the refinement of an intervention protocol to focus on prior STI and lack of condom use to increase the uptake of testing among this high-risk group.

Health care professional communication about STI vaccines with adolescents and parents

…. is sure design'd, by fraud or force: trust not their presents, nor admit the horse. Virgil, Aeneid Human immunodeficiency virus type 1 (HIV-1), the lymphotropic virus that causes AIDS, has infected more than 60 million people worldwide since its clinical appearance in 1981. Despite intensive prevention efforts, the HIV/AIDS epidemic continues to spread, particularly in developing countries in sub-Saharan Africa, southeast Asia and the Caribbean, as well as the developed world [1]. Although HIV can be transmitted very efficiently parenterally, the advent of routine blood screening prior to transfusion and harm reduction programs for injection drug users, have made this mode of transmission much less common than mucosal transmission. Most new HIV infections are attributable to mucosal transmission: through genital and rectal mucosae in the case of sexual transmission and through oral or gastrointestinal mucosae in the case of mother-to-child transmission [2]. Much has been learned about HIV pathogenesis and infection mechanisms at the molecular level, but the scientific community has yet to develop an effective vaccine or microbicide for HIV prevention. Many unanswered questions remain concerning HIV-1 sexual transmission. In 1983, barely 2 years into the AIDS epidemic, we hypothesized that the agent that was subsequently identified as HIV-1 may be sexually transmitted by infected ‘Trojan Horse’ leukocytes in semen [3]. This hypothesis was based on our knowledge at the time that human semen contains substantial numbers of T lymphocytes and macrophages, which could host a T-cell tropic virus, and the following assumptions: intracellular virus would be better protected than free virus from adverse effects of antiviral factors in the genital environment such as antiviral antibodies likely to be present in genital secretions of the virus-infected transmitter, as well as antimicrobial peptides that play an important role in genital innate immune defense; and virus-infected allogeneic cells could also escape early detection by major histocompatibility complex (MHC)-restricted cytotoxic T cells in a new host. Over the intervening 25+ years, others have also championed this cause [4,5], and convincing evidence has emerged from clinical research as well as in-vitro and animal studies that infected leukocytes indeed play a role in HIV transmission. Yet, most recent research on sexual HIV transmission has focused on cell-free HIV in genital secretions because of the wide availability of HIV RNA quantification assays. Furthermore, the majority of HIV vaccines and microbicides have been designed to block transmission of cell-free virus and have been tested in animal and in-vitro models that use cell-free virus as the only infectious inoculum. As the molecular events underlying cell-associated HIV transmission differ from those underlying cell-free virus transmission, many of the current vaccine and microbicide candidates might not be expected to protect against cell-associated HIV transmission. The failure of several recent vaccine and microbicide clinical trials may be due in part to this oversight. It should be possible to design strategies that block cell-associated HIV transmission as well as cell-free HIV transmission. In this article, we present an overview of research that has been conducted on cell-associated HIV mucosal transmission and recommendations for future research. We focus on sexual HIV transmission, but this review also has relevance for mother-to-child HIV transmission, which may occur through mucosal transmission of cell-associated HIV from maternal genital or mammary gland secretions [6–8]. We review published reports that describe and enumerate HIV-infected cells in genital secretions, and compelling evidence from clinical, animal and in-vitro studies demonstrating that such cells can transmit HIV across genital tract epithelial surfaces; potential molecular mechanisms underlying cell-associated HIV transmission that could be specifically targeted by future HIV prevention strategies; and in-vitro and animal cell-associated HIV transmission models currently used for studies on cell-associated HIV transmission mechanisms and for testing vaccine and microbicide candidates. Using this information as a foundation, we discuss the evidence and probability that various current microbicide and vaccine approaches prevent cell-associated HIV transmission, and suggest additional microbicide and vaccine concepts and experiments that will move this field forward.

2020 STD Prevention Conference: Disrupting Epidemics and Dismantling Disparities in the Time of COVID-19.

More than 30 pathogens, including bacteria, viruses, protozoa, and ectoparasites, cause sexually transmitted infections (STIs). Approximately 1 million curable STIs, comprising Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, and Trichomonas vaginalis, are acquired everyday worldwide. The most common of the treatable STIs is a protozoon, T. vaginalis, causing approximately 156 million new infections in 2020. Sexually transmitted viral infections are also prevalent worldwide, of which the most important are the human immunodeficiency virus (HIV), herpes simplex virus types 1 and 2, and the human papillomavirus (HPV). STIs impact people’s lives through their impact on reproductive health and child health, as well as through the facilitation of sexual transmission of HIV infection and, with some, such as HPV, as precursors of anogenital cancers. People face enormous challenges with access to health services for STI care. Furthermore, some STIs commonly exist as asymptomatic infections, particularly among adolescents. In addition, even with symptoms, some individuals have difficulty accessing affordable healthcare services because of anticipated stigma. The epidemiology of STIs is influenced by an interplay of the determinants of spread of infections and human behavior. At the individual level, determinant factors include ignorance of STIs, sexual behavior, sexual preferences, sexual networks, sex work, healthcare-seeking behaviors, and whether or not use is made of old and newer biomedical HIV and STI prevention interventions, such as condoms, medical male circumcision, and pre-exposure prophylaxis (e.g., PrEP for HIV); availability of, and access to, post-exposure prophylaxis; and prophylactic STI vaccines. At the population level, the determinants include demographic factors, socioeconomic factors, geographical settings, cultural ramifications, political commitment and health system responses. STIs can be prevented through modification of sexual behavior toward “safer sex.” The interventions implemented by countries, to varying degrees of coverage, include behavioral interventions, promotion of use of barrier methods, vaccinations, screening for STIs, and case-finding in people attending healthcare services for conditions other than for STI care. In persons with established infections, the focus is on averting short-term and long-term sequelae of untreated STIs, such as pelvic inflammatory disease, tubal-factor infertility, adverse pregnancy outcomes, and cervical cancer. This includes screening for asymptomatic STIs, cervical cancer, and the early diagnosis and treatment of HIV infection. Regular screening has been shown to reduce the population prevalence of STIs, prevention of some adverse outcomes such as congenital syphilis, and improved prognosis in such cases as early treatment of HPV-associated cervical cancer. The evidence and cost-effectiveness of screening for C. trachomatis and N. gonorrhoeae to prevent infertility and improve pregnancy outcomes is limited. Also, screening programs result in increased use of antibiotics in certain population groups, with concerns of increase in the development of antimicrobial resistance, especially in N. gonorrhoeae. The detection and management of STIs has been revolutionized since the 1990s by the development of molecular detection tests, the advent of STI vaccines, and the advent of new treatment molecules, such as antiretroviral treatments, which have facilitated timely diagnosis of both symptomatic and asymptomatic infections and converted some fatal infections into manageable chronic infections.

Predictors of STI vaccine acceptability among parents and their adolescent children

Patterns of Single and Multiple Claims of Epididymitis Among Young Privately-Insured Males in the United States, 2001 to 2004