No difference in sexual behavior of adolescent girls following Human Papilloma Virus vaccination: a case study two districts in Uganda; Nakasongola and Luwero

Review of mathematical models of Neisseria gonorrhoeae vaccine impact: Implications for vaccine development

An effective prophylactic vaccine for prevention of Neisseria gonorrhoeae infection would have a major impact on sexual and reproductive health worldwide. Interest in developing gonorrhoea vaccines is growing due to the reported high rates of N. gonorrhoeae infections globally, and the threat of antimicrobial resistance. Several gonorrhoea vaccine candidates are currently under evaluation and various mathematical models have been used to assess the potential population-level impact a gonorrhoea vaccine may have once available. Here we review key aspects of gonorrhoea vaccine mathematical modelling studies, including model structures, populations considered, and assumptions used as well as vaccine characteristics and implementation scenarios investigated. The predicted vaccine impact varied between studies, ranging from as little as ∼17 % reduction in N. gonorrhoeae prevalence after 30 years up to 100 % reduction after 5 years. However, all studies predicted that even a partially effective gonorrhoea vaccine could have a substantial impact in reducing N. gonorrhoeae prevalence or incidence, particularly when high coverage is achieved within either important risk groups or the overall sexually active population. As expected, higher vaccine efficacy against acquisition of N. gonorrhoeae and longer duration of protection were linked to greater reductions in infections. A vaccine that alters onward transmission could also substantially reduce infections. Several gaps and research needs have been identified by researchers in the field and via this narrative literature review. For example, future modelling to inform gonorrhoea vaccine development and implementation should consider additional populations that are at high risk of N. gonorrhoeae infection, especially in low- and middle-income settings, as well as the impact of vaccination on the potential adverse sexual and reproductive health outcomes of infection. In addition, more detailed and robust epidemiological, biological, and behavioural data is needed to enable more accurate and robust modelling of gonorrhoea vaccine impact to inform future scientific and public health decision-making.

The potential impact of a vaccine on Neisseria gonorrhoeae prevalence among heterosexuals living in a high prevalence setting

BACKGROUND

Treatment of Neisseria gonorrhoeae is under threat with the emergence and spread of antimicrobial resistance. Thus, there is a growing interest in the development of a gonorrhoea vaccine. We used mathematical modelling to assess the impact of a hypothetical vaccine in controlling gonorrhoea among heterosexuals living in a setting of relatively high N. gonorrhoeae prevalence (∼3 %).

METHODS

We developed a mathematical model of N. gonorrhoeae transmission among 15-49-year-old heterosexuals, stratified by age and sex, and calibrated to prevalence and sexual behaviour data from South Africa as an example of a high prevalence setting for which we have data available. Using this model, we assessed the potential impact of a vaccine on N. gonorrhoeae prevalence in the entire population. We considered gonorrhoea vaccines having differing impacts on N. gonorrhoeae infection and transmission and offered to different age-groups.

RESULTS

The model predicts that N. gonorrhoeae prevalence can be reduced by ∼50 % in 10 years following introduction of a vaccine if annual vaccination uptake is 10 %, vaccine efficacy against acquisition of infection is 25 % and duration of protection is 5 years, with vaccination available to the entire population of 15-49-year-olds. If only 15-24-year-olds are vaccinated, the predicted reduction in prevalence in the entire population is 25 % with equivalent vaccine characteristics and uptake. Although predicted reductions in prevalence for vaccination programmes targeting only high-activity individuals and the entire population are similar over the same period, vaccinating only high-activity individuals is more efficient as the cumulative number of vaccinations needed to reduce prevalence in the entire population by 50 % is ∼3 times lower for this programme.

CONCLUSION

Provision of a gonorrhoea vaccine could lead to substantial reductions in N. gonorrhoeae prevalence in a high prevalence heterosexual setting, even with moderate annual vaccination uptake of a vaccine with partial efficacy.

Sexual behavior, clinical outcomes and attendance of cervical cancer screening by HPV vaccinated and unvaccinated sexually active women

Concerns were raised about HPV vaccination possibly leading to riskier sexual behavior. We assessed sexual behaviors, risk of sexually transmitted infection, and attendance to cervical cancer screening by HPV vaccinated and unvaccinated young women. In this analysis, 1475 questionnaires completed by women aged 17-29 years were included. The majority of respondents (67.9%) were vaccinated against HPV. The proportion of those vaccinated decreased with age: from 93.2% in those aged 17-19 to 72.9% in those aged 20-22, and 21.8% in 23-29-year olds. A higher proportion of unvaccinated respondents had at least one sexual intercourse under the age of 15 when compared to those vaccinated (30% vs. 23%, p < .0001). The number of sexual partners during the last 12 months was similar between vaccinated and unvaccinated participants. Vaccinated participants reported more condom use (45% versus 38%; p = .0002), and less sexually transmitted infections (10% versus 28%; p < .0001), and less anogenital condylomas (2.2% vs. 11.6%; p < .0001). A screening test has been reported by 51% and 77% of vaccinated and unvaccinated participants, respectively (p < .0001). The association between vaccination status and cervical cancer screening disappeared when adjusting for participants' age. The study results consolidate the existing body of data regarding the absence of an impact of HPV vaccination on sexual behavior or use of contraceptives.

Effect of human papilloma virus vaccination on sexual behaviours among adolescent women in Rwanda: a regression discontinuity study

Increasing human papilloma virus (HPV) vaccination coverage is one of the key approaches to preventing cervical cancer globally. However, some argue that HPV vaccine recipients may engage in risky compensatory sexual behaviours because of perceived protection afforded by the vaccine. Therefore, we investigated the impact of a wide-scale HPV vaccination programme on sexual behaviours among adolescent women in Rwanda-the first African country to implement a national HPV vaccination. We identified a cohort of women who were eligible for the HPV vaccination and those who were not eligible from the most recent Rwanda Demographic and Health Survey. We used a quasi-experimental regression discontinuity design, exploiting the quasi-random change in HPV vaccination eligibility in 2011, to compare sexual behaviours among vaccinated and unvaccinated adolescent women. We studied the impact of the vaccination on reported sexual intercourse, average number of sexual partners and teenage pregnancy across the vaccination eligibility threshold. Our analysis included 3052 adolescent women (mean age: 18.6 years), of whom 58% were eligible for HPV vaccination. Nearly one in five adolescents reported having had sexual intercourse (18.5%). The average reported lifetime number of sexual partners was 1.41. The proportion of teenage pregnancy was 5.3%. We found no evidence that HPV vaccination was associated with any significant changes across the eligibility threshold in reported sexual behaviours we studied: no significant increase in the proportion of having sexual intercourse [odds ratio (OR): 0.80, 95% confidence interval (CI): 0.57-1.12; P = 0.19], in lifetime number of sexual partners (rate ratio 0.99, 95% CI: 0.83-1.17, P = 0.91) and in the proportion of teen pregnancies (OR 1.05, 95% CI: 0.50 to 2.20, P = 0.89) at the eligibility threshold. The Rwandan national HPV vaccination programme did not increase sexual behaviours among adolescent women, assuaging concerns of engaging in risky compensatory sexual behaviours some have feared.

Getting started in primary care research: choosing among six practical research approaches

While many primary care practitioners want to conduct research, many also struggle with getting started. This article’s purpose is to assist emerging researchers in identifying a topic of interest, to try the ‘fit’ of feasible research approaches and commit to a research approach. The article addresses six objectives: (1) identify how important primary care research comes from clinical stories; (2) recognise how clinical stories become the source of research topics; (3) discern how the research process resembles the care of patients; (4) distinguish the essential features of six research approaches feasible for primary care researchers; (5) evaluate the fit of the six research approaches featured in this special issue; and (6) develop a list of steps that need to be taken to implement primary care research projects. Using ‘HPV (human papilloma) vaccination’ as a hypothetical topic, the article illustrates how an emerging researcher can complete the worksheets. Using the HPV topic, a worksheet illustration shows how to complete the worksheets, and examples from the literature illustrate how actual studies have used six feasible research approaches for primary care: (1) survey research, (2) semistructured qualitative interviews, (3) curriculum development, (4) continuous quality improvement, (5) clinical policy analysis and (6) case study research. The worksheet exercises support choosing a feasible research approach for emerging researchers. Emerging researchers using these exercises can identify a topic, choose a research strategy aligned with the researcher’s interest, create a study title, develop a list of the next steps, and be well positioned to implement an original research project

Lessons learnt from human papillomavirus (HPV) vaccination in 45 low- and middle-income countries

OBJECTIVE

To synthesise lessons learnt and determinants of success from human papillomavirus (HPV) vaccine demonstration projects and national programmes in low- and middle-income countries (LAMICs).

METHODS

Interviews were conducted with 56 key informants. A systematic literature review identified 2936 abstracts from five databases; after screening 61 full texts were included. Unpublished literature, including evaluation reports, was solicited from country representatives; 188 documents were received. A data extraction tool and interview topic guide outlining key areas of inquiry were informed by World Health Organization guidelines for new vaccine introduction. Results were synthesised thematically.

RESULTS

Data were analysed from 12 national programmes and 66 demonstration projects in 46 countries. Among demonstration projects, 30 were supported by the GARDASIL® Access Program, 20 by Gavi, four by PATH and 12 by other means. School-based vaccine delivery supplemented with health facility-based delivery for out-of-school girls attained high coverage. There were limited data on facility-only strategies and little evaluation of strategies to reach out-of-school girls. Early engagement of teachers as partners in social mobilisation, consent, vaccination day coordination, follow-up of non-completers and adverse events was considered invaluable. Micro-planning using school/ facility registers most effectively enumerated target populations; other estimates proved inaccurate, leading to vaccine under- or over-estimation. Refresher training on adverse events and safe injection procedures was usually necessary.

CONCLUSION

Considerable experience in HPV vaccine delivery in LAMICs is available. Lessons are generally consistent across countries and dissemination of these could improve HPV vaccine introduction.

Cervical cancer risk perceptions, sexual risk behaviors and sexually transmitted infections among Bivalent Human Papillomavirus vaccinated and non-vaccinated young women in Uganda - 5 year follow up study

Background

Previous studies were conflicting regarding the associations between HPV vaccination, cervical cancer risk perceptions, high-risk sexual behaviors and STIs. This study compared the HPV-vaccinated and non-vaccinated young women in Uganda regarding cervical cancer risk perceptions, high-risk sexual behaviors, syphilis and HIV infections 5 years after vaccine implementation.

Methods

This was a population-based comparative cross-sectional survey conducted in Uganda. The 438 participants were sexually active young women aged 15–24 years and mean age was 18.6 (SD 1.4). The majority (53.0%) were HPV-vaccinated in 2008 without assessment of sexual activity prior to HPV vaccination. Upon verbal assessment of sexual activity at the time of follow-up, data were collected using a questionnaire and laboratory testing of blood samples for syphilis and HIV infections.

Results

There were no significant differences between the HPV-vaccinated and non-vaccinated groups regarding the prevalence of high-risk sexual behaviors, syphilis and HIV infections. Cervical cancer risk perceptions and age at sexual debut were nonetheless significantly lower among the vaccinated group compared to their non-vaccinated counterparts. However, HPV vaccination was not significantly associated to cervical cancer risk perceptions and early age at sexual debut in multivariate logistic regression analysis.

Conclusions

We found no associations between HPV vaccination, cervical cancer risk perceptions, high-risk sexual behaviors, syphilis and HIV infections among young women in Uganda 5 years after vaccine implementation. Young girls in the study population were found to be sexually active at a young age, affirming the importance of targeting girls of younger age for HPV vaccination.

Electronic supplementary material

The online version of this article (doi:10.1186/s12905-017-0394-y) contains supplementary material, which is available to authorized users.

Human Papillomavirus Vaccination and Sexual Disinhibition in Females: A Systematic Review

CONTEXT

Some parents believe human papillomavirus (HPV) vaccination increases the chance of risky sexual behaviors among adolescents. This review summarizes the evidence available on adolescent girls and women engaging in risky sexual activity following HPV vaccination.

EVIDENCE ACQUISITION

Systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in 2014 and updated in 2015. Literature was searched for articles published between 2004 and 2015 in MEDLINE, PsycInfo, CINAHL, Cochrane Database, Web of Science, and EMBASE without language limits. Studies were screened according to predefined inclusion and exclusion criteria. Methodologic quality of the included articles was assessed.

EVIDENCE SYNTHESIS

The search resulted in 21 articles to be included in the review, with 527,475 participants. Included studies were conducted in 12 different countries using experimental and observational study designs. The review included data on girls aged as young as 11 years to women aged 40 years. Studies measured changes in sexual behaviors using a variety of outcomes, including age at sexual debut; risky sexual behaviors; use of condoms and contraception; and clinical indicators such as rates of sexually transmitted infections, HIV, and pregnancy terminations. Available data showed either no association between vaccination status and the outcomes of interest or a positive association between safer sexual behaviors, such as condom use and receipt of HPV vaccination. Methodologic quality of all but one study was moderate or weak.

CONCLUSIONS

This review did not find sufficient evidence to support compensatory sexual risk behaviors following HPV vaccination among adolescent girls or women.

Tempest in a teapot: A systematic review of HPV vaccination and risk compensation research

There has been some concern among parents and in the media that vaccinating children against human papillomavirus could be seen as giving children permission to engage in risky sexual behaviors (also known as sexual disinhibition). Several studies have found this concern to be unfounded but there have been no attempts to synthesize the relevant studies in order to assess if there is evidence of sexual disinhibition. The aim of this study was to synthesize recent literature examining sexual behaviors and biological outcomes (e.g., sexually transmitted infections) post-HPV vaccination. We reviewed literature from January 1, 2008-June 30, 2015 using PubMed, CINAHL, and Embase with the following search terms: [(sex behavior OR sex behavior OR sexual) AND (human papillomavirus OR HPV) AND (vaccines OR vaccine OR vaccination)] followed by a cited reference search. We included studies that examined biological outcomes and reported behaviors post-vaccination in both males and females. Studies were reviewed by title and abstract and relevant studies were examined as full-text articles. We identified 2,503 articles and 20 were eventually included in the review. None of the studies of sexual behaviors and/or biological outcomes found evidence of riskier behaviors or higher rates of STIs after HPV vaccination. Instead, the studies found that vaccinated compared to unvaccinated individuals were less likely to report vaginal intercourse without a condom (OR = 0.5; 95%CI = 0.4-0.6) and non-use of contraception (OR = 0.27; 95%CI = 0.15-0.48) and unvaccinated participants had higher rates of Chlamydia (OR = 2.3; 95%CI = 1.06-5.00). These results should be reassuring to parents and health care providers.

The levels of anti-HPV16/18 and anti-HPV31/33/35/45/52/58 antibodies among AS04-adjuvanted HPV16/18 vaccinated and non-vaccinated Ugandan girls aged 10-16 years

BACKGROUND

Data on Human Papilloma virus (HPV) vaccine immune response in sub-Saharan Africa is still sparse yet such knowledge is critical for optimal implementation and monitoring of HPV vaccines. Our primary objective was to evaluate levels of anti-HPV-16/18 antibodies and six other 'high risk' HPV (hrHPV) types among the vaccinated and unvaccinated Ugandan girls.

METHODS

We conducted a cross sectional study among AS04-adjuvanted HPV-16/18 vaccinated and unvaccinated school girls aged 10-16 years in Western Uganda using purposive sampling. The vaccinated girls were at 18 months post vaccination. After consenting and assenting, data was collected using interviewer administered questionnaires for demographics and sexual history. Blood was drawn from which serum samples were analysed by the multiplex HPV serology technology to determine anti-HPV antibody levels to HPV-16/18 and six other hrHPV types (31, 33, 35, 45, 52 and 58). The antibody levels were expressed as Median Fluorescent Intensity (MFI). A total of 207 vaccinated [mean age 13.1 years (SD 1.5); range 10-16 years] and 197 unvaccinated girls [mean age 13.6 years (SD 1.3); range 10-16 years] participated in the study. Sexual activity was self reported among 14/207 (6.8%) vaccinated and 5/197 (2.5%) unvaccinated girls. The MFI levels for HPV-16 and HPV-18 were 15 and 20 times higher respectively in the vaccinated girls than in the unvaccinated girls. HPV-16 mean MFI level was 4691(SD 1812; 95% CI: 4438-4958) among the vaccinated compared to 218 (SD 685; 95% CI: 190-252) among the unvaccinated girls. For HPV-18 the mean MFI level was 1615 (SD 1326; 95% CI: 1470-1776) among the vaccinated compared to MFI 103 (SD 506; 95% CI: 88 -121) among unvaccinated girls. In addition antibody levels to non vaccine hrHPV types (31, 33, 35, 45, 52 and 58) were all significantly higher in the vaccinated group than in the unvaccinated group (p<0.01).

CONCLUSION

The AS04-Adjuvanted HPV-16/18 vaccinated girls showed a higher level of antibodies to HPV-16/18 and other non-vaccine hrHPV types compared to the unvaccinated girls. This may translate into protection against HPV-16/18 and other hrHPV types.