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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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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GAVI: 15 Years, 500 Million Vaccines

Via:  http://www.gavi.org/data-vis/  HT https://twitter.com/Gavi

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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