Typhoid fever vaccination strategies

Date, Kashmira; Bentsi-Enchill, Adwoa; Marks, Florian; Fox, Kimberley

doi:10.1016/j.vaccine.2015.04.028

Cited by 58 publications

(63 citation statements)

References 30 publications

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“…Almost all public health typhoid vaccination programs in the groups of populations at greatest risk have been performed in Asia (Table 1), with the strongest impact in endemic settings and in the short- to medium-term[37]. The oral vaccine was found to be highly cost-effective when targeting ages 1-14 years in high-burden/high-risk districts, as well urban slums and rural areas without improved water[38].…”

Section: Non Surgical Related Constraintsmentioning

confidence: 99%

Typhoid intestinal perforation in developing countries: Still unavoidable deaths?

Contini

2017

WJG

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Typhoid fever is a public health challenge mostly concentrated in impoverished, overcrowded areas of the developing world, with lack of safe drinking and sanitation. The most serious complication is typhoid intestinal perforation (TIP), observed in 0.8% to 39%, with a striking rate difference between high-income and low-middle-income countries. Although the mortality rate consequent to TIP in resource-poor countries is improved in the last decades, it is still fluctuating from 5% to 80%, due to surgical- and not surgical-related constraints. Huge economic costs and long timelines are required to provide a short- to middle-term solution to the lack of safe water and sanitation. Inherent limitations of the currently available diagnostic tools may lead to under-evaluation as well as over-evaluation of the disease, with consequent delayed treatment or inappropriate, excessive antibiotic use, hence increasing the likelihood of bacterial resistance. There is a need for immunization programs in populations at greatest risk, especially in sub-Saharan Africa. Uniform surgical strategies and guidelines, on the basis of sound or prospective surgical studies and adapted to the local realities, are still lacking. Major drawbacks of the surgical treatment are the frequent delays to surgery, either for late diagnosis or for difficult transports, and the unavailable appropriate intensive care units in most peripheral facilities. As a consequence, poor patient’s conditions at presentation, severe peritoneal contamination and unsuitable postoperative care are the foremost determinant of surgical morbidity and mortality.

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Section: Non Surgical Related Constraintsmentioning

confidence: 99%

Typhoid intestinal perforation in developing countries: Still unavoidable deaths?

Contini

2017

WJG

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“…Definitive diagnosis is through blood or bone-marrow culture, but is labor intensive, expensive, and invasive, and has a sensitivity of 40-80%. 2,3 WHO recommends routine TF vaccination, but currently, licensed vaccines, although moderately effective in adults (55-75% protection), 4,5 are largely ineffective in children under 5 years 6 of age, and are not widely used in endemic areas.…”

Section: Introductionmentioning

confidence: 99%

Serodiagnosis of Acute Typhoid Fever in Nigerian Pediatric Cases by Detection of Serum IgA and IgG Against Hemolysin E and Lipopolysaccharide

Davies

Jain

Nakajima

et al. 2016

The American Society of Tropical Medicine and Hygiene

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Abstract. Inexpensive, easy-to-use, and highly sensitive diagnostic tests are currently unavailable for typhoid fever. To identify candidate serodiagnostic markers, we have probed microarrays displaying the full Salmonella enterica serovar Typhi (S. Typhi) proteome of 4,352 different proteins + lipopolysaccharides (LPSs), with sera from Nigerian pediatric typhoid and other febrile cases, Nigerian healthy controls, and healthy U.S. adults. Nigerian antibody profiles were broad (∼500 seropositive antigens) and mainly low level, with a small number of stronger "hits," whereas the profile in U.S. adults was < 1/5 as broad, consistent with endemic exposure in Nigeria. Nigerian profiles were largely unaffected by clinical diagnosis, although the response against t1477 (hemolysin E) consistently emerged as stronger in typhoid cases. The response to LPS was also a strong discriminator of healthy controls and typhoid, although LPS did not discriminate between typhoid and nontyphoidal Salmonella (NTS) disease. As a first step toward the development of a point-of-care diagnostic, t1477 and LPS were evaluated on immunostrips. Both provided good discrimination between healthy controls and typhoid/NTS disease. Such a test could provide a useful screen for salmonellosis (typhoid and NTS disease) in suspected pediatric cases that present with undefined febrile disease.

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“…Beyond the advantage of inducing local immunity, oral vaccines are also subject to less stringent regulatory requirements for purification, and are very well suited for rapid mass vaccination as highly trained medical personnel are not needed for application. Nevertheless, currently only two oral vaccines against bacterial infection are licensed for use in humans: Salmonella enterica serovar Typhi (S. Typhi) (Vivotif TM ) [3] and Vibrio cholerae (V. cholerae) (Dukoral TM , Shanchol TM ) [4]. This reflects the difficulty of developing effective oral vaccines.…”

Section: Introductionmentioning

confidence: 99%

What Makes A Bacterial Oral Vaccine a Strong Inducer of High-Affinity IgA Responses?

Moor

Slack

2015

Antibodies

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Abstract:Oral vaccination against bacterial pathogens that infect via the gastrointestinal tract is highly desirable for both economic reasons and the supposed benefits of local mucosal immunity. However, the majority of oral vaccine trials in humans result in failure. Here we try to assimilate our current knowledge to generate a model to improve vaccine development strategies. A model previously postulated describes the "immunogenicity" of intestinal bacterial species as a sum of the ability of the species to compete with the microbiota, the "pathogenicity index," and the uniqueness of the species. While this model quite neatly explains the difficulties in generating appropriately attenuated live vaccine strains, it cannot explain the success of fully apathogenic or inactivated high-dose vaccines. We therefore propose a step away from focusing on bacterial traits, and towards the most basic requirements of mucosal vaccines: i.e., the delivery of antigen to the gut-associated lymphoid tissues and the ability of that antigen to induce germinal center formation. While the models seem trivial, both suggest that vaccination strategies permitting uncoupling of disease-causing phenomena from immune stimulation will have a much broader safety margin in a diverse human population. Our modified model further suggests the benefits of delivering antigen in the form of high-dose fully apathogenic or sterile particles, combined with relevant adjuvants. OPEN ACCESSAntibodies 2015, 4 296

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Typhoid fever vaccination strategies

Cited by 58 publications

References 30 publications

Typhoid intestinal perforation in developing countries: Still unavoidable deaths?

Typhoid intestinal perforation in developing countries: Still unavoidable deaths?

Serodiagnosis of Acute Typhoid Fever in Nigerian Pediatric Cases by Detection of Serum IgA and IgG Against Hemolysin E and Lipopolysaccharide

What Makes A Bacterial Oral Vaccine a Strong Inducer of High-Affinity IgA Responses?

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