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Vaccine Jul 2018Vibrio cholera is a major contributor of diarrheal illness that causes significant morbidity and mortality globally. While there is literature on the health economics of... (Review)
Review
BACKGROUND
Vibrio cholera is a major contributor of diarrheal illness that causes significant morbidity and mortality globally. While there is literature on the health economics of diarrheal illnesses more generally, few studies have quantified the cost-of-illness and cost-effectiveness of cholera-specific prevention and control interventions. The present systematic review provides a comprehensive overview of the literature specific to cholera as it pertains to key health economic measures.
METHODS
A systematic review was performed with no date restrictions up through February 2017 in PubMed, Econlit, Embase, Web of Science, and Cochrane Review to identify relevant health economics of cholera literature. After removing duplicates, a total of 1993 studies were screened and coded independently by two reviewers, resulting in 22 relevant studies. Data on population, methods, and results (cost-of-illness and cost-effectiveness of vaccination) were compared by country/region. All costs were adjusted to 2017 USD for comparability.
RESULTS
Costs per cholera case were found to be rather low: <$100 per case in most settings, even when costs incurred by patients/families and lost productivity are considered. When wider socioeconomic costs are included, estimated costs are >$1000/case. There is adequate evidence to support the economic value of vaccination for the prevention and control of cholera when vaccination is targeted at high-incidence populations and/or areas with high case fatality rates due to cholera. When herd immunity is considered, vaccination also becomes a cost-effective option for the general population and is comparable in cost-effectiveness to other routine immunizations.
CONCLUSIONS
Cholera vaccination is a viable short-to-medium term option, especially as the upfront costs of building water, sanitation, and hygiene (WASH) infrastructure are considerably higher for countries that face a significant burden of cholera. While WASH may be the more cost-effective solution in the long-term when implemented properly, cholera vaccination can still be a feasible, cost-effective strategy.
Topics: Cholera; Cost-Benefit Analysis; Humans; Vaccination
PubMed: 29907482
DOI: 10.1016/j.vaccine.2018.05.120 -
Paediatrics and International Child... Nov 2018Background Vibrio cholerae is a highly motile Gram-negative bacterium which is responsible for 3 million cases of diarrhoeal illness and up to 100,000 deaths per year,...
Background Vibrio cholerae is a highly motile Gram-negative bacterium which is responsible for 3 million cases of diarrhoeal illness and up to 100,000 deaths per year, with an increasing burden documented over the past decade. Current WHO guidelines for the treatment of paediatric cholera infection (tetracycline 12.5 mg/kg four times daily for 3 days) are based on data which are over a decade old. In an era of increasing antimicrobial resistance, updated review of the appropriate empirical therapy for cholera infection in children (taking account of susceptibility patterns, cost and the risk of adverse events) is necessary. Methods A systematic review of the current published literature on the treatment of cholera infection in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was undertaken. International clinical guidelines and studies pertaining to adverse effects associated with treatments available for cholera infection were also reviewed. Results The initial search produced 256 results, of which eight studies met the inclusion criteria. Quality assessment of the studies was performed as per the Grading of Recommendations Assessment, Development and Evaluation guidelines. Conclusions In view of the changing non-susceptibility rates worldwide, empirical therapy for cholera infection in paediatric patients should be changed to single-dose azithromycin (20 mg/kg), a safe and effective medication with ease of administration. Erythromycin (12.5 mg/kg four times daily for 3 days) exhibits similar bacteriological and clinical success and should be listed as a second-line therapy. Fluid resuscitation remains the cornerstone of management of paediatric cholera infection, and prevention of infection by promoting access to clean water and sanitation is paramount.
Topics: Adolescent; Anti-Bacterial Agents; Azithromycin; Child; Child, Preschool; Cholera; Drug Resistance, Bacterial; Drug-Related Side Effects and Adverse Reactions; Erythromycin; Guidelines as Topic; Humans; Infant; Infant, Newborn; Treatment Outcome; Vibrio cholerae; World Health Organization
PubMed: 29790841
DOI: 10.1080/20469047.2017.1409452 -
Prehospital and Disaster Medicine Feb 2018Introduction The efficacy of oral cholera vaccines (OCVs) in laboratory conditions has been established, and the World Health Organization (WHO; Geneva, Switzerland) has... (Meta-Analysis)
Meta-Analysis Review
UNLABELLED
Introduction The efficacy of oral cholera vaccines (OCVs) in laboratory conditions has been established, and the World Health Organization (WHO; Geneva, Switzerland) has recommended their preventative use in high-risk settings. The WHO recommendation has not been fully operationalized, nor has it been extended to apply to the reactive use of OCVs in real field epidemic conditions due to concerns about potential resource diversion, feasibility, cost, and acceptability. The purpose of this study is to assess and synthesize existing evidence of OCV effectiveness when used reactively in real field conditions.
METHODS
A systematic review and meta-analysis was conducted involving studies that investigated vaccine effectiveness when used as a reactive measure; that is, cases had reached epidemic threshold and a cholera epidemic was declared in real field epidemic conditions. OVID Medline (US National Library of Medicine, National Institutes of Health; Bethesda, Maryland USA), CINAHL (EBSCO Information Services; Ipswich, Massachusetts USA), and EMBASE (Elsevier; Amsterdam, Netherlands), along with grey literature, were systematically searched using pre-determined criteria. Two independent reviewers identified studies that met the selection criteria and data were extracted using validated tools. Pooled estimates were obtained using fixed effect models.
RESULTS
Of the 347 articles that met the inclusion criteria, four studies were retrieved for meta-analysis (three were case-control studies and one was a case-cohort study) involving a total of 1,509 participants and comprising 175 cases and 1,334 case controls. The effectiveness of one or two doses of either Shanchol (Shantha Biotechnics; India) or ORC-Vax (Vabiotech; Vietnam) OCVs showed a combined vaccine effectiveness of 75% (95% CI, 61-84).
CONCLUSION
A positive association was demonstrated between the reactive use of OCVs and protection against cholera. This supported the WHO recommendation to utilize OCVs reactively as an additional measure to the standard cholera epidemic response package. Schwerdtle P , Onekon CK , Recoche K . A quantitative systematic review and meta-analysis of the effectiveness of oral cholera vaccine as a reactive measure in cholera outbreaks. Prehosp Disaster Med. 2018;33(1):2-6.
Topics: Administration, Oral; Cholera; Cholera Vaccines; Disease Outbreaks; Evaluation Studies as Topic; Female; Global Health; Humans; Incidence; Male; World Health Organization
PubMed: 29317005
DOI: 10.1017/S1049023X17007166 -
Health and Human Rights Dec 2017The 2008-2009 Zimbabwe cholera epidemic resulted in 98,585 reported cases and caused more than 4,000 deaths. In this study, we used a mixed-methods approach that... (Review)
Review
The 2008-2009 Zimbabwe cholera epidemic resulted in 98,585 reported cases and caused more than 4,000 deaths. In this study, we used a mixed-methods approach that combined primary qualitative data from a 2008 Physicians for Human Rights-led investigation with a systematic review and content analysis of the scientific literature. Our initial investigation included semi-structured interviews of 92 key informants, which we supplemented with reviews of the social science and human rights literature, as well as international news reports. Our systematic review of the scientific literature retrieved 59 unique citations, of which 30 met criteria for inclusion in the content analysis: 14 of the 30 (46.7%) articles mentioned the political dimension of the epidemic, while 7 (23.3%) referenced Mugabe or his political party (ZANU-PF). Our investigation revealed that the 2008-2009 Zimbabwean cholera epidemic was exacerbated by a series of human rights abuses, including the politicization of water, health care, aid, and information. The failure of the scientific community to directly address the political determinants of the epidemic exposes challenges to maintaining scientific integrity in the setting of humanitarian responses to complex health and human rights crises. While the period of the cholera epidemic and the health care system collapse is now nearly a decade in the past, the findings of this work remain highly relevant for Zimbabwe and other countries, as complex health and rights interactions remain widespread, and governance concerns continue to limit improvements in human health.
Topics: Cholera; Delivery of Health Care; Epidemics; Government; Human Rights; Humans; Politics
PubMed: 29302180
DOI: No ID Found -
Clinical Infectious Diseases : An... Jun 2018In addition to improved water supply and sanitation, the 2-dose killed oral cholera vaccine (OCV) is an important tool for the prevention and control of cholera. We... (Meta-Analysis)
Meta-Analysis
In addition to improved water supply and sanitation, the 2-dose killed oral cholera vaccine (OCV) is an important tool for the prevention and control of cholera. We aimed to document the immunogenicity and protection (efficacy and effectiveness) conferred by a single OCV dose against cholera. The metaanalysis showed that an estimated 73% and 77% of individuals seroconverted to the Ogawa and Inaba serotypes, respectively, after an OCV first dose. The estimates of single-dose vaccine protection from available studies are 87% at 2 months decreasing to 33% at 2 years. Current immunologic and clinical data suggest that protection conferred by a single dose of killed OCV may be sufficient to reduce short-term risk in outbreaks or other high-risk settings, which may be especially useful when vaccine supply is limited. However, until more data suggest otherwise, a second dose should be given as soon as circumstances allow to ensure robust protection.
Topics: Administration, Oral; Cholera; Cholera Vaccines; Disease Outbreaks; Humans; Immunization Schedule; Immunogenicity, Vaccine; Seroconversion; Serogroup; Vaccination; Vaccine Potency; Vaccines, Inactivated; Vibrio cholerae
PubMed: 29177437
DOI: 10.1093/cid/cix1039 -
Human Vaccines & Immunotherapeutics Feb 2018World Health Organization recommends oral cholera vaccine (OCV) to prevent and control cholera, but requires cost-effectiveness evidence. This review aimed to provide a...
World Health Organization recommends oral cholera vaccine (OCV) to prevent and control cholera, but requires cost-effectiveness evidence. This review aimed to provide a critical appraisal and summary of global economic evaluation (EE) studies involving OCV to guide future EE study. Full EE studies, published from inception to December 2015, evaluating OCV against cholera disease were included. The included studies were appraised using WHO guide for standardization of EE of immunization programs. Out of 14 included studies, almost all (13/14) were in low- and middle-income countries. Most studies (11/14) evaluated mass vaccination program. Most of the studies (9/14) incorporated herd protective effect. The most common influential parameters were cholera incidence, OCV coverage, herd protection and OCV price. OCV vaccination is likely to be cost-effective when targeted at the population with high-risk of cholera and poor access to health care facilities when herd protection effect is incorporated and OCV price is low.
Topics: Cholera; Cholera Vaccines; Developing Countries; Humans; Immunization Programs; World Health Organization
PubMed: 29099647
DOI: 10.1080/21645515.2017.1392422 -
The American Journal of Tropical... Nov 2017Globally, approximately 2 billion people lack microbiologically safe drinking water. Boiling is the most prevalent household water treatment method, yet evidence of its... (Meta-Analysis)
Meta-Analysis Review
Globally, approximately 2 billion people lack microbiologically safe drinking water. Boiling is the most prevalent household water treatment method, yet evidence of its health impact is limited. To conduct this systematic review, we searched four online databases with no limitations on language or publication date. Studies were eligible if health outcomes were measured for participants who reported consuming boiled and untreated water. We used reported and calculated odds ratios (ORs) and random-effects meta-analysis to estimate pathogen-specific and pooled effects by organism group and nonspecific diarrhea. Heterogeneity and publication bias were assessed using , meta-regression, and funnel plots; study quality was also assessed. Of the 1,998 records identified, 27 met inclusion criteria and reported extractable data. We found evidence of a significant protective effect of boiling for infections (OR = 0.31, 95% confidence interval [CI] = 0.13-0.79, = 4 studies), (OR = 0.35, 95% CI = 0.17-0.69, = 3), protozoal infections overall (pooled OR = 0.61, 95% CI = 0.43-0.86, = 11), viral infections overall (pooled OR = 0.83, 95% CI = 0.7-0.98, = 4), and nonspecific diarrheal outcomes (OR = 0.58, 95% CI = 0.45-0.77, = 7). We found no evidence of a protective effect for helminthic infections. Although our study was limited by the use of self-reported boiling and non-experimental designs, the evidence suggests that boiling provides measureable health benefits for pathogens whose transmission routes are primarily water based. Consequently, we believe a randomized controlled trial of boiling adherence and health outcomes is needed.
Topics: Developing Countries; Diarrhea; Drinking Water; Food Contamination; Food Microbiology; Humans; Water Microbiology; Water Purification; Waterborne Diseases
PubMed: 29016318
DOI: 10.4269/ajtmh.17-0190 -
The Lancet. Infectious Diseases Oct 2017Killed whole-cell oral cholera vaccines (kOCVs) are becoming a standard cholera control and prevention tool. However, vaccine efficacy and direct effectiveness estimates... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Killed whole-cell oral cholera vaccines (kOCVs) are becoming a standard cholera control and prevention tool. However, vaccine efficacy and direct effectiveness estimates have varied, with differences in study design, location, follow-up duration, and vaccine composition posing challenges for public health decision making. We did a systematic review and meta-analysis to generate average estimates of kOCV efficacy and direct effectiveness from the available literature.
METHODS
For this systematic review and meta-analysis, we searched PubMed, Embase, Scopus, and the Cochrane Review Library on July 9, 2016, and ISI Web of Science on July 11, 2016, for randomised controlled trials and observational studies that reported estimates of direct protection against medically attended confirmed cholera conferred by kOCVs. We included studies published on any date in English, Spanish, French, or Chinese. We extracted from the published reports the primary efficacy and effectiveness estimates from each study and also estimates according to number of vaccine doses, duration, and age group. The main study outcome was average efficacy and direct effectiveness of two kOCV doses, which we estimated with random-effect models. This study is registered with PROSPERO, number CRD42016048232.
FINDINGS
Seven trials (with 695 patients with cholera) and six observational studies (217 patients with cholera) met the inclusion criteria, with an average two-dose efficacy of 58% (95% CI 42-69, I=58%) and effectiveness of 76% (62-85, I=0). Average two-dose efficacy in children younger than 5 years (30% [95% CI 15-42], I=0%) was lower than in those 5 years or older (64% [58-70], I=0%; p<0·0001). Two-dose efficacy estimates of kOCV were similar during the first 2 years after vaccination, with estimates of 56% (95% CI 42-66, I=45%) in the first year and 59% (49-67, I=0) in the second year. The efficacy reduced to 39% (13 to 57, I=48%) in the third year, and 26% (-46 to 63, I=74%) in the fourth year.
INTERPRETATION
Two kOCV doses provide protection against cholera for at least 3 years. One kOCV dose provides at least short-term protection, which has important implications for outbreak management. kOCVs are effective tools for cholera control.
FUNDING
The Bill & Melinda Gates Foundation.
Topics: Administration, Oral; Cholera; Cholera Vaccines; Humans; Vaccines, Inactivated
PubMed: 28729167
DOI: 10.1016/S1473-3099(17)30359-6 -
PLoS Neglected Tropical Diseases Jun 2017Infectious diseases attributable to unsafe water supply, sanitation and hygiene (e.g. Cholera, Leptospirosis, Giardiasis) remain an important cause of morbidity and... (Review)
Review
Infectious diseases attributable to unsafe water supply, sanitation and hygiene (e.g. Cholera, Leptospirosis, Giardiasis) remain an important cause of morbidity and mortality, especially in low-income countries. Climate and weather factors are known to affect the transmission and distribution of infectious diseases and statistical and mathematical modelling are continuously developing to investigate the impact of weather and climate on water-associated diseases. There have been little critical analyses of the methodological approaches. Our objective is to review and summarize statistical and modelling methods used to investigate the effects of weather and climate on infectious diseases associated with water, in order to identify limitations and knowledge gaps in developing of new methods. We conducted a systematic review of English-language papers published from 2000 to 2015. Search terms included concepts related to water-associated diseases, weather and climate, statistical, epidemiological and modelling methods. We found 102 full text papers that met our criteria and were included in the analysis. The most commonly used methods were grouped in two clusters: process-based models (PBM) and time series and spatial epidemiology (TS-SE). In general, PBM methods were employed when the bio-physical mechanism of the pathogen under study was relatively well known (e.g. Vibrio cholerae); TS-SE tended to be used when the specific environmental mechanisms were unclear (e.g. Campylobacter). Important data and methodological challenges emerged, with implications for surveillance and control of water-associated infections. The most common limitations comprised: non-inclusion of key factors (e.g. biological mechanism, demographic heterogeneity, human behavior), reporting bias, poor data quality, and collinearity in exposures. Furthermore, the methods often did not distinguish among the multiple sources of time-lags (e.g. patient physiology, reporting bias, healthcare access) between environmental drivers/exposures and disease detection. Key areas of future research include: disentangling the complex effects of weather/climate on each exposure-health outcome pathway (e.g. person-to-person vs environment-to-person), and linking weather data to individual cases longitudinally.
Topics: Climate; Communicable Diseases; Models, Biological; Water Microbiology; Weather
PubMed: 28604791
DOI: 10.1371/journal.pntd.0005659 -
The Cochrane Database of Systematic... Dec 2016Acute diarrhoea is one of the main causes of morbidity and mortality among children in low-income countries. Glucose-based oral rehydration solution (ORS) helps replace... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Acute diarrhoea is one of the main causes of morbidity and mortality among children in low-income countries. Glucose-based oral rehydration solution (ORS) helps replace fluid and prevent further dehydration from acute diarrhoea. Since 2004, the World Health Organization (WHO) has recommended the osmolarity of less than 270 mOsm/L (ORS ≤ 270) versus greater than 310 mOsm/L formulation (ORS ≥ 310). Polymer-based ORS (for example, prepared using rice or wheat) slowly releases glucose and may be superior to glucose-based ORS.
OBJECTIVES
To compare polymer-based oral rehydration solution (polymer-based ORS) with glucose-based oral rehydration solution (glucose-based ORS) for treating acute watery diarrhoea.
SEARCH METHODS
We searched the following sources up to 5 September 2016: the Cochrane Infectious Diseases Group (CIDG) Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 9), MEDLINE (1966 to 5 September 2016), EMBASE (1974 to 5 September 2016), LILACS (1982 to 5 September 2016), and mRCT (2007 to 5 September 2016). We also contacted researchers, organizations, and pharmaceutical companies, and searched reference lists.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) of people with acute watery diarrhoea (cholera and non-cholera associated) that compared polymer-based and glucose-based ORS (with identical electrolyte contents).
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed the search results and risk of bias, and extracted data. In multiple-treatment arms with two or more treatment groups, we combined outcomes as appropriate and compared collectively with the control group.
MAIN RESULTS
Thirty-five trials that included 4284 participants met the inclusion criteria: 28 trials exclusively included children, five included adults, and two included both adults and children. Polymer-based ORS versus glucose-based ORS (osmolarity ≤ 270) Eight trials (752 participants) evaluated this comparison, and seven trials used rice as a polymer source. Polymer-based ORS may decrease mean stool output in the first 24 hours by 24 mL/kg (mean difference (MD) -24.60 mL/kg, 95% CI -40.69 to -8.51; one trial, 99 participants, low quality evidence). The average duration of diarrhoea may be reduced by eight hours (MD -8.24 hours, 95% CI -13.17 to -3.30; I² statistic = 86%, five trials, 364 participants, low quality evidence) with polymer ORS but results are heterogeneous. Limited trials showed no observed difference in the risk of unscheduled use of intravenous fluid (RR 0.66, 95% CI 0.43 to 1.02; I² statistic = 30%; four trials, 376 participants, very low quality evidence), vomiting (very low quality evidence), and hyponatraemia (very low quality evidence). Polymer-based ORS versus glucose-based ORS (osmolarity ≥ 310) Twenty-seven trials (3532 participants) evaluated this comparison using a variety of polymers. On average, polymer ORS may reduce the total stool output in the first 24 hours by around 65 mL/kg (MD -65.47 mL/kg, 95% CI -83.92 to -47.03; 16 trials, 1483 participants, low quality evidence), and may reduce the duration of diarrhoea by around eight hours (MD -8.57 hours; SD -13.17 to -4.03; 16 trials, 1137 participants, low quality evidence) with substantial heterogeneity. The proportion of participants that required intravenous hydration was low in most trials with fewer in the polymer ORS group (RR 0.75, 95% CI 0.57 to 0.98; 19 trials, 1877 participant, low quality evidence) . Subgroup analysis by type of pathogen suggested an effect on unscheduled intravenous fluid in those infected with mixed pathogens (RR 0.63, 95% CI 0.41 to 0.96; 11 trials, 928 participants, low quality evidence), but not in participants positive for Vibrio cholerae (RR 0.94, 95% CI 0.66 to 1.34; 7 trials, 535 participants, low quality evidence). No difference was observed in the number of patients who developed vomiting (RR 0.91, 95% CI 0.72 to 1.14; 10 trials, 584 participants, very low quality evidence), hyponatraemia (RR 1.82, 95% CI 0.52 to 6.44; 4 trials, 385 participants, very low quality evidence), hypokalaemia (RR 1.29, 95% CI 0.74 to 2.25; 2 trials, 260 participants, low quality evidence), or persistent diarrhoea (RR 1.28, 95% CI 0.68 to 2.41; 2 trials, 885 participants, very low quality evidence).
AUTHORS' CONCLUSIONS
Polymer-based ORS shows advantages compared to glucose-based ORS (at ≥ 310 mOsm/L). Comparisons favoured polymer-based ORS over ORS ≤ 270 but analysis was underpowered.
Topics: Acute Disease; Adult; Child; Cholera; Dehydration; Diarrhea; Fluid Therapy; Humans; Infant; Oryza; Polymers; Randomized Controlled Trials as Topic; Rehydration Solutions
PubMed: 27959472
DOI: 10.1002/14651858.CD006519.pub3