-
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 -
PLoS Neglected Tropical Diseases Dec 2016Use of the oral cholera vaccine (OCV) is a vital short-term strategy to control cholera in endemic areas with poor water and sanitation infrastructure. Identifying,... (Review)
Review
BACKGROUND
Use of the oral cholera vaccine (OCV) is a vital short-term strategy to control cholera in endemic areas with poor water and sanitation infrastructure. Identifying, estimating, and categorizing the delivery costs of OCV campaigns are useful in analyzing cost-effectiveness, understanding vaccine affordability, and in planning and decision making by program managers and policy makers.
OBJECTIVES
To review and re-estimate oral cholera vaccination program costs and propose a new standardized categorization that can help in collation, analysis, and comparison of delivery costs across countries.
DATA SOURCES
Peer reviewed publications listed in PubMed database, Google Scholar and World Health Organization (WHO) websites and unpublished data from organizations involved in oral cholera vaccination.
STUDY ELIGIBILITY CRITERIA
The publications and reports containing oral cholera vaccination delivery costs, conducted in low- and middle-income countries based on World Bank Classification. Limits are humans and publication date before December 31st, 2014.
PARTICIPANTS
No participants are involved, only costs are collected.
INTERVENTION
Oral cholera vaccination and cost estimation.
STUDY APPRAISAL AND SYNTHESIS METHOD
A systematic review was conducted using pre-defined inclusion and exclusion criteria. Cost items were categorized into four main cost groups: vaccination program preparation, vaccine administration, adverse events following immunization and vaccine procurement; the first three groups constituting the vaccine delivery costs. The costs were re-estimated in 2014 US dollars (US$) and in international dollar (I$).
RESULTS
Ten studies were identified and included in the analysis. The vaccine delivery costs ranged from US$0.36 to US$ 6.32 (in US$2014) which was equivalent to I$ 0.99 to I$ 16.81 (in I$2014). The vaccine procurement costs ranged from US$ 0.29 to US$ 29.70 (in US$2014), which was equivalent to I$ 0.72 to I$ 78.96 (in I$2014). The delivery costs in routine immunization systems were lowest from US$ 0.36 (in US$2014) equivalent to I$ 0.99 (in I$2014).
LIMITATIONS
The reported cost categories are not standardized at collection point and may lead to misclassification. Costs for some OCV campaigns are not available and analysis does not include direct and indirect costs to vaccine recipients.
CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS
Vaccine delivery cost estimation is needed for budgeting and economic analysis of vaccination programs. The cost categorization methodology presented in this study is helpful in collecting OCV delivery costs in a standardized manner, comparing delivery costs, planning vaccination campaigns and informing decision-making.
Topics: Administration, Oral; Cholera; Cholera Vaccines; Cost-Benefit Analysis; Humans; Immunization Programs; Poverty; Sanitation; Vaccination; World Health Organization
PubMed: 27930668
DOI: 10.1371/journal.pntd.0005124 -
SpringerPlus 2016Vibrio parahaemolyticus is an important seafood borne human pathogen worldwide due to it occurrence, prevalence and ability to cause gastrointestinal infections. This...
Vibrio parahaemolyticus is an important seafood borne human pathogen worldwide due to it occurrence, prevalence and ability to cause gastrointestinal infections. This current study aim at investigating the incidence and prevalence of V. parahaemolyticus in seafood using systematic review-meta-analysis by exploring heterogeneity among primary studies. A comprehensive systematic review and meta-analysis of peer reviewed primary studies reported between 2003 and 2015 for the occurrence and prevalence of V. parahaemolyticus in seafood was conducted using "isolation", "detection", "prevalence", "incidence", "occurrence" or "enumeration" and V. parahaemolyticus as search algorithms in Web of Science (Science Direct) and ProQuest of electronic bibliographic databases. Data extracted from the primary studies were then analyzed with fixed effect meta-analysis model for effect rate to explore heterogeneity between the primary studies. Publication bias was evaluated using funnel plot. A total of 10,819 articles were retrieved from the data bases of which 48 studies met inclusion criteria. V. parahaemolyticus could only be isolated from 2761 (47.5 %) samples of 5811 seafood investigated. The result of this study shows that incidence of V. parahaemolyticus was more prevalent in oysters with overall prevalence rate of 63.4 % (95 % CI 0.592-0.674) than other seafood. Overall prevalence rate of clams was 52.9 % (95 % CI 0.490-0.568); fish 51.0 % (95 % CI 0.476-0.544); shrimps 48.3 % (95 % CI 0.454-0.512) and mussels, scallop and periwinkle: 28.0 % (95 % CI 0.255-0.307). High heterogeneity (p value <0.001; I (2) = 95.291) was observed mussel compared to oysters (I (2) = 91.024). It could be observed from this study that oysters harbor V. parahaemolyticus based on the prevalence rate than other seafood investigated. The occurrence and prevalence of V. parahaemolyticus is of public health importance, hence, more studies involving seafood such as mussels need to be investigated.
PubMed: 27119068
DOI: 10.1186/s40064-016-2115-7 -
Medicine Feb 2016Vibrio vulnificus necrotizing skin and soft tissue infections (VNSSTIs), which have increased significantly over the past few decades, are still highly lethal and... (Meta-Analysis)
Meta-Analysis Review
Vibrio vulnificus necrotizing skin and soft tissue infections (VNSSTIs), which have increased significantly over the past few decades, are still highly lethal and disabling diseases despite advancing antibiotic and infection control practices. We, therefore, examined the spatiotemporal distribution of worldwide reported episodes and associated mortality rates of VNSSTIs between 1966 and 2014. The PubMed and Cochrane Library databases were systematically searched for observational studies on patients with VNSSTIs. The primary outcome was all-cause mortality. We did random-effects meta-analysis to obtain estimates for primary outcomes; the estimates are presented as means plus a 95% confidence interval (CI). Data from the selected studies were also extracted and pooled for correlation analyses.Nineteen studies of 2227 total patients with VNSSTIs were analyzed. More than 95% of the episodes occurred in the subtropical western Pacific and Atlantic coastal regions of the northern hemisphere. While the number of cases and the number of deaths were not correlated with the study period (rs = 0.476 and 0.310, P = 0.233 and 0.456, respectively), the 5-year mortality rate was significantly negatively correlated with them (rs = -0.905, P = 0.002). Even so, the pooled estimate of total mortality rates from the random-effects meta-analysis was as high as 37.2% (95% CI: 0.265-0.479).These data suggest that VNSSTIs are always an important public health problem and will become more critical and urgent because of global warming. Knowing the current distribution of VNSSTIs will help focus education, policy measures, early clinical diagnosis, and appropriate medical and surgical treatment for them.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Female; Humans; Infant; Male; Middle Aged; Skin Diseases, Bacterial; Soft Tissue Infections; Spatio-Temporal Analysis; Vibrio Infections; Young Adult
PubMed: 26844475
DOI: 10.1097/MD.0000000000002627 -
PloS One 2015Cholera remains a significant threat to global public health with an estimated 100,000 deaths per year. Water, sanitation and hygiene (WASH) interventions are frequently... (Review)
Review
BACKGROUND AND METHODS
Cholera remains a significant threat to global public health with an estimated 100,000 deaths per year. Water, sanitation and hygiene (WASH) interventions are frequently employed to control outbreaks though evidence regarding their effectiveness is often missing. This paper presents a systematic literature review investigating the function, use and impact of WASH interventions implemented to control cholera.
RESULTS
The review yielded eighteen studies and of the five studies reporting on health impact, four reported outcomes associated with water treatment at the point of use, and one with the provision of improved water and sanitation infrastructure. Furthermore, whilst the reporting of function and use of interventions has become more common in recent publications, the quality of studies remains low. The majority of papers (>60%) described water quality interventions, with those at the water source focussing on ineffective chlorination of wells, and the remaining being applied at the point of use. Interventions such as filtration, solar disinfection and distribution of chlorine products were implemented but their limitations regarding the need for adherence and correct use were not fully considered. Hand washing and hygiene interventions address several transmission routes but only 22% of the studies attempted to evaluate them and mainly focussed on improving knowledge and uptake of messages but not necessarily translating this into safer practices. The use and maintenance of safe water storage containers was only evaluated once, under-estimating the considerable potential for contamination between collection and use. This problem was confirmed in another study evaluating methods of container disinfection. One study investigated uptake of household disinfection kits which were accepted by the target population. A single study in an endemic setting compared a combination of interventions to improve water and sanitation infrastructure, and the resulting reductions in cholera incidence.
DISCUSSION AND RECOMMENDATIONS
This review highlights a focus on particular routes of transmission, and the limited number of interventions tested during outbreaks. There is a distinct gap in knowledge of which interventions are most appropriate for a given context and as such a clear need for more robust impact studies evaluating a wider array of WASH interventions, in order to ensure effective cholera control and the best use of limited resources.
Topics: Cholera; Disease Outbreaks; Humans; Hygiene; Sanitation; Water Purification
PubMed: 26284367
DOI: 10.1371/journal.pone.0135676 -
PloS One 2015Maternal infection with cholera may negatively affect pregnancy outcomes. The objective of this research is to systematically review the literature and determine the... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Maternal infection with cholera may negatively affect pregnancy outcomes. The objective of this research is to systematically review the literature and determine the risk of fetal, neonatal and maternal death associated with cholera during pregnancy.
MATERIALS AND METHODS
Medline, Global Health Library, and Cochrane Library databases were searched using the key terms cholera and pregnancy for articles published in any language and at any time before August 2013 to quantitatively summarize estimates of fetal, maternal, and neonatal mortality. 95% confidence intervals (CIs) were calculated for each selected study. Random-effect non-linear logistic regression was used to calculate pooled rates and 95% CIs by time period. Studies from the recent period (1991-2013) were compared with studies from 1969-1990. Relative risk (RR) estimates and 95% CIs were obtained by comparing mortality of selected recent studies with published national normative data from the closest year.
RESULTS
The meta-analysis included seven studies that together involved 737 pregnant women with cholera from six countries. The pooled fetal death rate for 4 studies during 1991-2013 was 7.9% (95% CIs 5.3-10.4), significantly lower than that of 3 studies from 1969-1990 (31.0%, 95% CIs 25.2-36.8). There was no difference in fetal death rate by trimester. The pooled neonatal death rate for 1991-2013 studies was 0.8% (95% CIs 0.0-1.6), and 6.4% (95% CIs 0.0-20.8) for 1969-1990. The pooled maternal death rate for 1991-2013 studies was 0.2% (95% CIs 0.0-0.7), and 5.0% (95% CIs 0.0-16.0) for 1969-1990. Compared with published national mortality estimates, the RR for fetal death of 5.8 (95% CIs 2.9-11.3) was calculated for Haiti (2013), 1.8 (95% CIs 0.3-10.4) for Senegal (2007), and 2.6 (95% CIs 0.5-14.9) for Peru (1991); there were no significant differences in the RR for neonatal or maternal death.
CONCLUSION
Results are limited by the inconsistencies found across included studies but suggest that maternal cholera is associated with adverse pregnancy outcomes, particularly fetal death. These findings can inform a research agenda on cholera in pregnancy and guidance for the timely management of pregnant women with cholera.
Topics: Cholera; Female; Fetal Mortality; Haiti; Humans; India; Infant; Infant Mortality; Infant, Newborn; Maternal Mortality; Pakistan; Peru; Pregnancy; Pregnancy Complications, Infectious; Pregnancy Outcome; Senegal
PubMed: 26177291
DOI: 10.1371/journal.pone.0132920 -
Bulletin of the World Health... Dec 2014To describe and analyse the characteristics of oral cholera vaccination campaigns; including location, target population, logistics, vaccine coverage and delivery costs. (Review)
Review
OBJECTIVE
To describe and analyse the characteristics of oral cholera vaccination campaigns; including location, target population, logistics, vaccine coverage and delivery costs.
METHODS
We searched PubMed, the World Health Organization (WHO) website and the Cochrane database with no date or language restrictions. We contacted public health personnel, experts in the field and in ministries of health and did targeted web searches.
FINDINGS
A total of 33 documents were included in the analysis. One country, Viet Nam, incorporates oral cholera vaccination into its public health programme and has administered approximately 10.9 million vaccine doses between 1997 and 2012. In addition, over 3 million doses of the two WHO pre-qualified oral cholera vaccines have been administered in more than 16 campaigns around the world between 1997 and 2014. These campaigns have either been pre-emptive or reactive and have taken place under diverse conditions, such as in refugee camps or natural disasters. Estimated two-dose coverage ranged from 46 to 88% of the target population. Approximate delivery cost per fully immunized person ranged from 0.11-3.99 United States dollars.
CONCLUSION
Experience with oral cholera vaccination campaigns continues to increase. Public health officials may draw on this experience and conduct oral cholera vaccination campaigns more frequently.
Topics: Administration, Oral; Cholera; Cholera Vaccines; Global Health; Humans; Immunization Programs; Public Health Practice; Vietnam; World Health Organization
PubMed: 25552772
DOI: 10.2471/BLT.14.139949