Dataset Information

Sex-specific immunization for sexually transmitted infections such as human papillomavirus: insights from mathematical models.

ABSTRACT: BACKGROUND: Sex-specific differences regarding the transmissibility and the course of infection are the rule rather than the exception in the epidemiology of sexually transmitted infections (STIs). Human papillomavirus (HPV) provides an example: disease outcomes differ between men and women, as does the potential for transmission to the opposite sex. HPV vaccination of preadolescent girls was recently introduced in many countries, and inclusion of boys in the vaccination programs is being discussed. Here, we address the question of whether vaccinating females only, males only, or both sexes is the most effective strategy to reduce the population prevalence of an STI like HPV. METHODS AND FINDINGS: We use a range of two-sex transmission models with varying detail to identify general criteria for allocating a prophylactic vaccine between both sexes. The most effective reduction in the population prevalence of infection is always achieved by single-sex vaccination; vaccinating the sex with the highest prevaccine prevalence is the preferred strategy in most circumstances. Exceptions arise only when the higher prevaccine prevalence is due to a substantially lower rate of natural immunity, or when natural immunity is lifelong, and a prolonged duration of infectiousness coincides with increased transmissibility. Predictions from simple models were confirmed in simulations based on an elaborate HPV transmission model. Our analysis suggests that relatively inefficient genital transmission from males to females might render male vaccination more effective in reducing overall infection levels. However, most existing HPV vaccination programs have achieved sufficient coverage to continue with female-only vaccination. CONCLUSIONS: Increasing vaccine uptake among preadolescent girls is more effective in reducing HPV infection than including boys in existing vaccination programs. As a rule, directing prophylactic immunization at the sex with the highest prevaccine prevalence results in the largest reduction of the population prevalence.

SUBMITTER: Bogaards JA

PROVIDER: S-EPMC3243713 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Sex-specific immunization for sexually transmitted infections such as human papillomavirus: insights from mathematical models.

Bogaards Johannes A JA Kretzschmar Mirjam M Xiridou Maria M Meijer Chris J L M CJ Berkhof Johannes J Wallinga Jacco J

PLoS medicine 20111220 12

<h4>Background</h4>Sex-specific differences regarding the transmissibility and the course of infection are the rule rather than the exception in the epidemiology of sexually transmitted infections (STIs). Human papillomavirus (HPV) provides an example: disease outcomes differ between men and women, as does the potential for transmission to the opposite sex. HPV vaccination of preadolescent girls was recently introduced in many countries, and inclusion of boys in the vaccination programs is being ...[more]

PMID: 22205887

Similar Datasets

Project description:BACKGROUND:Sexual mixing between heterogeneous population subgroups is an integral component of mathematical models of sexually transmitted infections (STIs). This study compares the fit of different mixing representations to survey data and the impact of different mixing assumptions on the predicted benefits of hypothetical human papillomavirus (HPV) vaccine strategies. METHODS:We compared novel empirical (data-driven) age mixing structures with the more commonly-used assortative-proportionate (A-P) mixing structure. The A-P mixing structure assumes that a proportion of sexual contacts - known as the assortativity constant, typically estimated from survey data or calibrated - occur exclusively within one's own age group and the remainder mixes proportionately among all age groups. The empirical age mixing structure was estimated from the National Survey on Sexual Attitudes and Lifestyles 3 (Natsal-3) using regression methods, and the assortativity constant was estimated from Natsal-3 as well. Using a simplified HPV transmission model under each mixing assumption, we calibrated the model to British HPV16 prevalence data, then estimated the reduction in steady-state prevalence and the number of infections averted due to expanding HPV vaccination from 12- through 26-year-old females alone to 12-year-old males or 27- to 39-year-old females. RESULTS:Empirical mixing provided a better fit to the Natsal-3 data than the best-fitting A-P structure. Using the model with empirical mixing as a reference, the model using the A-P structure often under- or over-estimated the benefits of vaccination, in one case overestimating by 2-fold the number of infections prevented due to extended female catch-up in a high vaccine uptake setting. CONCLUSIONS:An empirical mixing structure more accurately represents sexual mixing survey data, and using the less accurate, yet commonly-used A-P structure has a notable effect on estimates of HPV vaccination benefits. This underscores the need for mixing structures that are less dependent on unverified assumptions and are directly informed by sexual behavior data.

Project description:Sexually transmitted infections (STIs) such as herpes simplex virus (HSV)-2 are associated with an increased risk of HIV infection. Human papillomavirus (HPV) is a common STI, but little is know about its role in HIV transmission. The objective of this study was to determine whether cervico-vaginal HPV infection increases the risk of HIV acquisition in women independent of other common STIs.This prospective cohort study followed 2040 HIV-negative Zimbabwean women (average age 27 years, range 18-49 years) for a median of 21 months. Participants were tested quarterly for 29 HPV types (with L1 PCR primers) and HIV (antibody testing on blood samples with DNA or RNA PCR confirmation). HIV incidence was 2.7 per 100 woman-years. Baseline HPV prevalence was 24.5%, and the most prevalent HPV types were 58 (5.0%), 16 (4.7%), 70 (2.4%), and 18 (2.3%). In separate regression models adjusting for baseline variables (including age, high risk partner, positive test for STIs, positive HSV-2 serology and condom use), HIV acquisition was associated with having baseline prevalent infection with HPV 58 (aHR 2.13; 95% CI 1.09-4.15) or HPV 70 (aHR 2.68; 95% CI 1.08-6.66). In separate regression models adjusting for both baseline variables and time-dependent variables (including HSV-2 status, incident STIs, new sexual partner and condom use), HIV acquisition was associated with concurrent infection with any non-oncogenic HPV type (aHR 1.70; 95% CI 1.02-2.85), any oncogenic HPV type (aHR 1.96; 95% CI 1.16-3.30), HPV 31 (aHR 4.25; 95% CI 1.81-9.97) or HPV 70 (aHR 3.30; 95% CI 1.50-7.20). Detection of any oncogenic HPV type within the previous 6 months was an independent predictor of HIV acquisition, regardless of whether HPV status at the HIV acquisition visit was included (aHR 1.95; 95% CI 1.19-3.21) or excluded (aHR 1.96; 95% CI 1.02-2.85) from the analysis.Cervico-vaginal HPV infection was associated with an increased risk of HIV acquisition in women, and specific HPV types were implicated in this association. The observational nature of our study precludes establishment of causation between HPV infection and HIV acquisition. However, given the high prevalence of HPV infection in women, further investigation of the role of HPV in HIV transmission is warranted.

Project description:OBJECTIVE:To evaluate the validity and acceptability of at-home self-collection to test for high-risk human papillomavirus (HPV) and sexually transmitted infections among women overdue for cervical cancer screening by national guidelines. METHODS:Low-income, infrequently screened women were recruited from the general population in North Carolina to participate in an observational study. Participants provided two self-collected cervicovaginal samples (one at home and one in the clinic) and a clinician-collected cervical sample. Samples were tested for high-risk HPV, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Mycoplasma genitalium. Cervical samples were also tested by liquid-based cytology. RESULTS:Overall, 193 women had conclusive high-risk HPV results for all three samples and cytology results. Prevalence of high-risk HPV within self-home samples (12.4%) was not different from that within clinician samples (11.4%; P=.79) and from that within self clinic samples (15.5%; P=.21). Positivity for high-risk HPV in all sample types increased with increasing grades of cervical abnormality (P<.001). Self-home samples detected high-risk HPV in all identified cases of high-grade squamous intraepithelial lesions and of cervical intraepithelial neoplasia 2 or worse. Detection was comparable across sample types for T vaginalis (range 10.2-10.8%), M genitalium (3.3-5.5%), C trachomatis (1.1-2.1%), and N gonorrhoeae (0-0.5%). Kappa values between sample types ranged from 0.56 to 0.66 for high-risk HPV, 0.86-0.91 for T vaginalis, and 0.65-0.83 for M genitalium. Most participants reported no difficulty understanding self-collection instructions (93.6%) and were willing to use self-collection in the future (96.3%). CONCLUSION:Mail-based, at-home self-collection for high-risk HPV and sexually transmitted infection detection was valid and well accepted among infrequently screened women in our study. These findings support the future use of high-risk HPV self-collection to increase cervical cancer screening rates among higher risk women in the United States.

Dataset Information

Sex-specific immunization for sexually transmitted infections such as human papillomavirus: insights from mathematical models.

Publications

Sex-specific immunization for sexually transmitted infections such as human papillomavirus: insights from mathematical models.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets