The Potential Impact of Vaccination on the Prevalence of Gonorrhea

Gonorrhea, one of the most common sexually transmitted infections worldwide, can lead to serious sequelae, including infertility and increased HIV transmission. 

Recently, untreatable, multidrug-resistant Neisseria gonorrhoeae strains have been reported. In the absence of new antibiotics, and given the speed with which resistance has emerged to all previously used antibiotics, development of a vaccine would be the ideal solution to this public health emergency. 

Understanding the desired characteristics, target population, and expected impact of an anti-gonococcal vaccine is essential to facilitate vaccine design, assessment and implementation. The modeling presented herein aims to fill these conceptual gaps, and inform future gonococcal vaccine development. 

Using an individual-based, epidemiological simulation model, gonococcal prevalence was simulated in a heterosexual population of 100,000 individuals after the introduction of vaccines with varied efficacy (10–100%) and duration of protection (2.5–20 years). Model simulations predict that gonococcal prevalence could be reduced by at least 90% after 20 years, if all 13-year-olds were given a non-waning vaccine with 50% efficacy, or a vaccine with 100% efficacy that wanes after 7.5 years. A 40% reduction in prevalence is achievable with a non-waning vaccine of only 20% efficacy. 

We conclude that a vaccine of moderate efficacy and duration could have a substantive impact on gonococcal prevalence, and disease sequelae, if coverage is high and protection lasts over the highest risk period (i.e., most sexual partner change) among young people.

Below:  The prevalence of gonorrhea in the absence of a vaccine, and with (A) vaccines of differing efficacies and 20 years duration of protection, or (B) vaccines with 100% efficacy and of differing durations of protection. Vaccine coverage is 100% of 13-year-olds.

Below:  The prevalence of gonorrhea in the absence of a vaccine, and with different rates and types of vaccine coverage. (A) Vaccines have 100% efficacy and 20 years duration. (B) Vaccines have 50% efficacy and 20 years duration.

By:  Andrew P. Craig,a Richard T. Gray,a Jennifer L. Edwards,b Michael A. Apicella,c Michael P. Jennings,d David P. Wilson,#a and Kate L. Seib#d,*

^a The Kirby Institute, UNSW Australia, Sydney 2052, NSW, Australia

^b Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and The Ohio State University Department of Pediatrics, Columbus, OH, USA

^c Department of Microbiology, University of Iowa, Iowa City, IA, USA

^d Institute for Glycomics, Griffith University, Southport, QLD, Australia

^#Contributed equally.

^* Corresponding author. Tel.: +61 755527453; fax: +61 7 5552 8098. Email: ua.ude.htiffirg@bies.k (K.L. Seib).

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Recent Update in HIV Vaccine Development

Despite the tremendous efforts to develop a successful human immunodeficiency virus (HIV) vaccine, the quest for a safe and effective HIV vaccine seems to be remarkably long and winding. Disappointing results from previous clinical trials of VaxGen's AIDSVAXgp120 vaccine and MRKAd5 HIV-1 Gag/Pol/Nef vaccine emphasize that understanding the correlates of immune protection in HIV infection is the key to solve the puzzle. The modest vaccine efficacy from RV144 trial and the successive results obtained from the correlate of risk analysis have reinvigorated the HIV vaccine research field leading to various novel strategies. This paper will review the brief history and recent advances in HIV vaccine development.

…To date, RV144 trial is the only trial of a vaccine against HIV-1 to show any degree of efficiency. The modest vaccine efficacy from RV144 trial and the successive results obtained from the correlate of risk analysis have reinvigorated the HIV vaccine research field leading to various novel strategies. Although the quest to develop a successful HIV vaccine is long and winding, our understanding of viral immunology and immune correlate of protection has progressed remarkably during the journey. We now are starting to have a glimpse of correlate of protection in HIV infection, better understanding of the immune pathway leading to effective antibodies and newer form of vaccine immunogens. The ultimate goal of the quest to develop the successful HIV vaccine is not yet accomplished but it is evident that we are entering the modern era of HIV vaccinology.

Below:  Schematic drawing of human immunodeficiency virus type 1 Env trimer with sites of epitopes for broadly neutralizing antibodies. Adapted and modified from Haynes et al. (2012), Nat Biotechnol 2012;30:423-33 [30]. The currently known four general specificity for broadly neutralizing antibodies detected are the CD4 binding site, the V1/V2 variable loops, certain exposed glycans and the membrane proximal external region (MPER). Structures expressed as follows: blue, gp120 core; dark blue, V1/V2 loops; magenta, V3 loop; green, gp41; red, MPER of gp41; light gray, viral membrane bilayer.

Full article at:   http://goo.gl/6S1alY

By:  So Youn Shin

Department of Infectious Diseases, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea.

Corresponding author.

Corresponding author: So Youn Shin, MD, PhD. Department of Infectious Diseases, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, 25 Simgok-ro 100beon-gil, Seo-gu, Incheon 22711, Korea. Tel: +82-32-290-3975, Fax: +82-32-290-4240, Email:moc.liamtoh@soreeehcysp

Clin Exp Vaccine Res. 2016 Jan; 5(1): 6–11. Published online 2016 Jan 27. doi:  10.7774/cevr.2016.5.1.6

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Risk of Invasive Meningococcal Disease in Children & Adults with HIV in England

Background

Recent studies have identified HIV infection as a potential risk factor for invasive meningococcal disease (IMD), suggesting that HIV-infected individuals could benefit from meningococcal vaccination to reduce their risk of this rare, but severe and potentially fatal infection. In the United Kingdom, as in most industrialised countries, HIV is not considered a risk factor for IMD.

Methods

IMD incidence and relative risk by age group and meningococcal capsular group in HIV-positive compared with HIV-uninfected individuals was estimated through data linkage of national datasets in England between 2011 and 2013.

Results

IMD incidence among persons diagnosed with HIV was 6.6 per 100,000 compared to 1.5 per 100,000 among HIV-negative individuals, with a relative risk of 4.5 (95 % CI, 2.7–7.5). All but one case occurred in adults aged 16–64 years, who had a 22.7-fold (95 % CI, 12.4–41.6; P <0.001) increased risk compared with the HIV-negative adults. IMD risk by capsular group varied with age. HIV-positive children and adolescents had a higher risk of meningococcal group B disease, while adults were at increased risk of groups C, W and Y disease. Most HIV-positive individuals had been born in Africa, had acquired HIV through heterosexual contact, and were known to be HIV-positive and receiving antiretroviral treatment at IMD diagnosis. The most common clinical presentation was septicemia and, although intensive care admission was common, none died of IMD.

Conclusions

HIV-positive children and adults are at significantly increased risk of IMD, providing an evidence base for policy makers to consider HIV as a risk factor for meningococcal vaccination.

Full article at:  http://goo.gl/uGXzsr

By:  Ruth D. Simmons^1*, Peter Kirwan², Kazim Beebeejaun¹, Andrew Riordan³, Ray Borrow⁴,Mary E. Ramsay¹, Valerie Delpech², Samuel Lattimore¹ and Shamez Ladhani¹

¹Immunisation Department, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK

²HIV and STI Department, Public Health England, London, UK

³Royal Liverpool Children’s Hospital, Liverpool, UK

⁴Vaccine Evaluation Unit, Public Health England, Manchester, UK

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A Home-School-Doctor Model to Break the Barriers for Uptake of Human Papillomavirus Vaccine

A high coverage of human papillomavirus (HPV) vaccination is required to achieve a clinically significant reduction in disease burden. Countries implementing free-of-charge national vaccination program for adolescent girls are still challenged by the sub-optimal uptake rate. Voluntary on-site school-based mass vaccination programs have demonstrated high coverage. Here, we tested whether this could be an option for countries without a government-supported vaccination program as in Hong Kong.

A Home-School-Doctor model was evolved based on extensive literature review of various health promotion models together with studies on HPV vaccination among adolescent girls. The outcome measure was uptake of vaccination. Factors associated with the outcome were measured by validated surveys in which 4,631 students from 24 school territory wide participated. Chi-square test was used to analyze association between the categorical variables and the outcome. Multivariate analysis was performed to identify independent variables associated with the outcome with vaccine group as case and non-vaccine group as control.

In multivariate analysis, parental perception of usefulness of the Home-School-Doctor model had a very high odds ratio for uptake of HPV vaccination (OR 26.6, 95 % CI 16.4, 41.9). Paying a reasonable price was another independent factor associated with increased uptake (OR 1.71, 95 % CI 1.39, 2.1 for those with parents willing to pay US$125-250 for vaccination). For parents and adolescents who were not sure where to get vaccination, this model was significantly associated with improved uptake rate (OR 1.66, 95 % CI 1.23, 2.23). Concerns with side effects of vaccine (OR 0.70, 95 % CI 0.55, 0.88), allowing daughters to make their own decisions (OR 0.49, 95 % CI 0.38, 0.64) and not caring much about daughters’ social life (95 % CI 0.45, 0.92) were factors associated with a lower uptake.

The findings of this study have added knowledge on how a school-based vaccination program would improve vaccine uptake rate even when the users need to pay. Our findings are consistent with other study that the most acceptable way to achieve high uptake of HPV vaccine is to offer voluntary school-based vaccination.

A model of care incorporating the efforts and expertise of academics and health professionals working closely with school can be applied to improve the uptake of vaccine among adolescent girls. Subsidized voluntary school-based vaccination scheme can be an option.

Below:  Reasons not refusing HPV vaccination in the past

Below: Framework for Health Behavioural Modification at different levels

Read more at:  http://ht.ly/SvnZu 

By: Albert Lee^13*, Martin CS Wong¹, Tracy TN Chan³ and Paul KS Chan²

¹JC School of Public Health and Primary Care, The Chinese University of Hong Kong, 4th Floor, School of Public Heath, Prince of Wales Hospital, Shatin, New Territories, Hong Kong

²Department of Microbiology, The Chinese University of Hong Kong, 1st Floor, Clinical Sciences Building, Prince of Wales Hospital, Shatin, New Territories, Hong Kong

³Centre for Health Education and Health Promotion, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, 4th Floor, Lek Yuen Health Centre, Shatin, New Territories

Monitoring Effect of Human Papillomavirus Vaccines in US Population, Emerging Infections Program, 2008–2012

Below:  Prevalence of human papillomavirus (HPV) types among women with a diagnosis of cervical intraepithelial neoplasia grade 2 or 3 or adenocarcinoma in situ, Emerging Infections Program HPV-IMPACT project, 2008–2012. HPV-16 and -18 are the most common oncogenic HPV types; HPV-6 and -11 are nononcogenic HPV types that cause genital warts and respiratory papillomatosis.

In 2007, five Emerging Infections Program (EIP) sites were funded to determine the feasibility of establishing a population-based surveillance system for monitoring the effect of human papillomavirus (HPV) vaccine on pre-invasive cervical lesions. The project involved active population-based surveillance of cervical intraepithelial neoplasia grades 2 and 3 and adenocarcinoma in situ as well as associated HPV types in women >18 years of age residing in defined catchment areas; collecting relevant clinical information and detailed HPV vaccination histories for women 18–39 years of age; and estimating the annual rate of cervical cancer screening among the catchment area population. The first few years of the project provided key information, including data on HPV type distribution, before expected effect of vaccine introduction. The project’s success exemplifies the flexibility of EIP’s network to expand core activities to include emerging surveillance needs beyond acute infectious diseases. Project results contribute key information regarding the impact of HPV vaccination in the United States.

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If there was a vaccine against cancer, wouldn't you get it for your keiki?

Via:  http://ht.ly/QErc8  Posters at: (boy) http://ht.ly/QEqTI (girl) http://ht.ly/QEr0e 

Direct Benefit of Vaccinating Boys Along with Girls Against Oncogenic Human Papillomavirus: Bayesian Evidence Synthesis

Below:  Burden of HPV associated cancers in men in the Netherlands in relation to vaccine coverage of girls, overall and separately for carcinomas of oropharynx, anus, and penis. White bars (posterior median plus 1 SD) denote QALYs lost to all HPV types, whereas coloured bars denote estimated burden from vaccine preventable HPV types 16 and 18

Results Before HPV vaccination, 14.9 (95% credible interval 12.2 to 18.1) QALYs per thousand men were lost to vaccine preventable cancers associated with HPV in the Netherlands. This burden would be reduced by 37% (28% to 48%) if the vaccine uptake among girls remains at the current level of 60%. To prevent one additional case of cancer among men, 795 boys (660 to 987) would need to be vaccinated; with tumour specific numbers for anal, penile, and oropharyngeal cancer of 2162, 3486, and 1975, respectively. The burden of HPV related cancer in men would be reduced by 66% (53% to 805) if vaccine uptake among girls increases to 90%. In that case, 1735 boys (1240 to 2900) would need to be vaccinated to prevent an additional case; with tumour specific numbers for anal, penile, and oropharyngeal cancer of 2593, 29107, and 6484, respectively.

Conclusions Men will benefit indirectly from vaccination of girls but remain at risk of cancers associated with HPV. The incremental benefit of vaccinating boys when vaccine uptake among girls is high is driven by the prevention of anal carcinomas, which underscores the relevance of HPV prevention efforts for men who have sex with men.

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