Can cholera 'hotspots' be converted to cholera 'coldspots' in cholera endemic countries? The Matlab, Bangladesh experience

Safety and effectiveness of a recombinant hepatitis E vaccine in women of childbearing age in rural Bangladesh: a phase 4, double-blind, cluster-randomised, controlled trial

BACKGROUND

Hepatitis E virus (HEV) leads to high mortality in pregnant women in low-income countries. We aimed to evaluate the safety of a HEV vaccine and its effectiveness in preventing hepatitis E during pregnancy.

METHODS

In this phase 4, double-blind, cluster-randomised trial, 67 villages in Matlab, Bangladesh, were randomised 1:1 to receive HEV239 (a recombinant HEV vaccine) or a control vaccine (Hepa-B, a hepatitis B vaccine), using block randomisation with random number tables and blocks of size eight, stratified by cluster population size. Eligible non-pregnant women (aged 16-39 years) were vaccinated intramuscularly on day 0, at 1 month, and at 6 months, and followed up for 2 years after the last immunisation. The primary endpoint was hepatitis E in the pregnant, per-protocol population (those who received all three doses within 2 days of the scheduled dates), while safety was a secondary endpoint, assessed in the intention-to-treat (ITT) population (participants who received at least one dose). Solicited adverse events were recorded for the first 7 days after each dose, and unsolicited events until 2 years after a participant's final dose. Pregnancy-related safety outcomes were assessed in the pregnant ITT population. This study is registered with ClinicalTrials.gov (NCT02759991).

FINDINGS

Between Oct 2, 2017, and Feb 28, 2019, 19 460 participants were enrolled and received either HEV239 (9478 [48·7%] participants, 33 clusters) or Hepa-B (9982 [51·3%] participants, 34 clusters), of whom 17 937 (92·2%) participants received three doses and 17 613 (90·5%) were vaccinated according to protocol (8524 [48·4%] in the HEV239 group and 9089 [51·6%] in the control group). No pregnant participants were confirmed to have hepatitis E in either treatment group. HEV239 showed a mild safety profile, similar to Hepa-B, with no difference in the proportion of solicited adverse events between groups and no severe solicited events. Pain was the most common local symptom (1215 [12·8%] HEV239 recipients and 1218 [12·2%] Hepa-B recipients) and fever the most common systemic symptom (141 [1·5%] HEV239 recipients and 145 [1·5%] Hepa-B recipients). None of the serious adverse events or deaths were vaccine related. Among pregnant participants, the HEV239 group had a higher risk of miscarriage (136 [5·7%] of 2407 pregnant participants) compared with the control group (102 [3·9%] of 2604; adjusted odds ratio 1·54 [95% CI 1·15-2·08]).

INTERPRETATION

The effectiveness of HEV239 in pregnant women remains uncertain. HEV239 was safe and well tolerated in non-pregnant women, but findings regarding miscarriage warrant further investigation.

FUNDING

Research Council of Norway; Innovax.

Vibrio cholerae in rural and urban Bangladesh, findings from hospital-based surveillance, 2000-2021

With more than 100,000 cases estimated each year, Bangladesh is one of the countries with the highest number of people at risk for cholera. Moreover, Bangladesh is formulating a countrywide cholera-control plan to satisfy the GTFCC (The Global Task Force on Cholera Control) Roadmap's goals. With a particular focus on cholera trends, variance in baseline and clinical characteristics of cholera cases, and trends in antibiotic susceptibility among clinical isolates of Vibrio cholerae, we used data from facility-based surveillance systems from icddr,b's Dhaka, and Matlab Hospitals from years 2000 to 2021. Female patients comprised 3,553 (43%) in urban and 1,099 (51.6%) in rural sites. Of the cases and most patients 5,236 (63.7%) in urban and 1,208 (56.7%) in the rural site were aged 15 years and more. More than 50% of the families belonged to the poor and lower-middle-class; in 2009 (24.4%) were in urban and in 1,791 (84.2%) were in rural sites. In the urban site, 2,446 (30%) of households used untreated drinking water, and 702 (9%) of families disposed of waste in their courtyard. In the multiple logistic regression analysis, the risk of cholera has significantly increased due to waste disposal in the courtyard and the boiling of water has a protective effect against cholera. Rotavirus (9.7%) was the most prevalent co-pathogen among the under-5 children in both sites. In urban sites, the percentage of V. cholerae along with co-existing ETEC and Campylobacter is changing in the last 20 years; Campylobacter (8.36%) and Enterotoxigenic Escherichia coli (ETEC) (7.15%) were the second and third most prevalent co-pathogens. Shigella (1.64%) was the second most common co-pathogen in the rural site. Azithromycin susceptibility increased slowly from 265 (8%) in 2006-2010 to 1485 (47.8%) in 2016-2021, and erythromycin susceptibility dropped substantially over 20 years period from 2,155 (98.4%) to 21 (0.9%). Tetracycline susceptibility decreased in the urban site from 2051 (45.9%) to 186 (4.2%) and ciprofloxacin susceptibility decreased from 2,581 (31.6%) to 1,360 (16.6%) until 2015, then increased 1,009 (22.6%) and 1,490 (18.2%) in 2016-2021, respectively. Since 2016, doxycycline showed 902 (100%) susceptibility. Clinicians need access to up-to-date information on antimicrobial susceptibility for treating hospitalized patients. To achieve the WHO-backed objective of eliminating cholera by 2030, the health systems need to be put under a proper surveillance system that may help to improve water and sanitation practices and deploy oral cholera vaccines strategically.

Hidden Costs of the COVID-19 Pandemic Response

"First, do no harm" [...].

The interplay between WASH practices and vaccination with oral cholera vaccines in protecting against cholera in urban Bangladesh: Reanalysis of a cluster-randomized trial

The current global initiative to end Cholera by 2030 emphasizes the use of oral cholera vaccine (OCV) combined with feasible household Water-Sanitation-Hygiene (WASH) interventions. However, little is known about how improved WASH practices and behaviors and OCV interact to reduce the risk of cholera. We reanalyzed two arms of a cluster-randomized trial in urban Bangladesh, to evaluate the effectiveness of OCV given as a 2-dose regimen. One arm (30 clusters, n = 94,675) was randomized to vaccination of persons aged one year and older with OCV, and the other arm (30 clusters, n = 80,056) to no intervention. We evaluated the prevention of cholera by household WASH, classified at baseline using a previously validated rule, and OCV over 2 years of follow-up. When analyzed by assignment to OCV clusters rather than receipt of OCV, in comparison to persons living in "Not Better WASH" households in the control clusters, reduction of severe cholera (the primary outcome) was similar for persons in "Not Better WASH" households in vaccine clusters (46%, 95% CI:24,62), for persons in "Better WASH" households in the control clusters (48%, 95% CI:25,64), and for persons in "Better WASH" households in the vaccine clusters (48%, 95% CI:16,67). In contrast, when analyzed by actual receipt of a complete OCV regimen, , in comparison to persons in "Not Better WASH" households in the control clusters, protection against severe cholera increased steadily from 39% (95% CI:13,58) in residents of "Better WASH" households in the control clusters to 57% (95% CI:35,72) in vaccinated persons in "Not Better WASH" households to 63% (95% CI:21,83) in vaccinated persons in "Better WASH" households. This analysis suggests that improved household WASH and OCV received may interact to provide greater protection against cholera. However, the divergence between findings related to intent to vaccinate versus those pertaining to actual receipt of OCV underscores the need for further research on this topic.

Influence of Seasonal Hazards on Water, Sanitation, and Hygiene-Related Behavior and Implications for Cholera Transmission in Bangladesh

Most cholera outbreaks in Bangladesh are seasonal, peaking in the dry and post-monsoon periods. Therefore, we investigated whether changes in water, sanitation, and hygiene (WASH) behavior in three populations in Bangladesh during the year could help explain why these two periods are particular to cholera transmission. The study used a mixed-method design, including a repeated cross-sectional study, focus group discussions, and key informant interviews. Through a repeated cross-sectional study, WASH-related variables were assessed during the dry, monsoon, and control seasons in 600 households from coastal Satkhira, inland Sirajganj, and the Dhaka slums. Seasonal behavioral changes were observed in all study areas. Dhaka and Satkhira had an increased mean distance to water sources during the dry and monsoon seasons (Dhaka: control season, 12 m [95% CI, 11-13]; dry season, 36 m [95% CI, 18-55]; and monsoon season, 180 m [95% CI, 118-243]; Satkhira: control season, 334 m [95% CI, 258-411]; dry season, 669 m [95% CI, 515-822]; and monsoon season, 2,437 m [95% CI, 1,665-3,209]). The participants attributed this to pollution of the usual water source. Perceived water quantity was lowest during the dry season in Dhaka and Sirajganj, and during the monsoon season in Satkhira. Handwashing with soap declined in all areas during the dry and monsoon seasons. Open defecation was frequent among children younger than 5 years, increasing during seasonal climate hazards. Results show that WASH-related behavior changed seasonally, increasing the risk of cholera transmission through multiple hygiene-related transmission pathways. Future research would benefit by ensuring that the length of studies covers all seasons throughout the year and also by looking in more detail at people's behavior and hygiene practices.

Multiscale model for forecasting Sabin 2 vaccine virus household and community transmission

Since the global withdrawal of Sabin 2 oral poliovirus vaccine (OPV) from routine immunization, the Global Polio Eradication Initiative (GPEI) has reported multiple circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks. Here, we generated an agent-based, mechanistic model designed to assess OPV-related vaccine virus transmission risk in populations with heterogeneous immunity, demography, and social mixing patterns. To showcase the utility of our model, we present a simulation of mOPV2-related Sabin 2 transmission in rural Matlab, Bangladesh based on stool samples collected from infants and their household contacts during an mOPV2 clinical trial. Sabin 2 transmission following the mOPV2 clinical trial was replicated by specifying multiple, heterogeneous contact rates based on household and community membership. Once calibrated, the model generated Matlab-specific insights regarding poliovirus transmission following an accidental point importation or mass vaccination event. We also show that assuming homogeneous contact rates (mass action), as is common of poliovirus forecast models, does not accurately represent the clinical trial and risks overestimating forecasted poliovirus outbreak probability. Our study identifies household and community structure as an important source of transmission heterogeneity when assessing OPV-related transmission risk and provides a calibratable framework for expanding these analyses to other populations. Trial Registration: ClinicalTrials.gov This trial is registered with clinicaltrials.gov, NCT02477046.

Characteristics of Rotavirus, ETEC, and Vibrio Cholerae Among Under 2-year Children Attending an Urban Diarrheal Disease Hospital in Bangladesh

Background

Information on comparative clinical and host characteristics of under-2 children with watery diarrhea caused by rotavirus, Enterotoxigenic Escherichia coli (ETEC), and Vibrio cholerae as single pathogens is lacking. We sought to investigate the sociodemographic, clinical, and host characteristics of under-2 children hospitalized due to these pathogens.

Methodology

We conducted a hospital-based case-control study using the icddr,b Diarrheal Diseases Surveillance System. Children of either sex, <2 years with diarrhea, who attended the hospital during 2014 to 2018, constituted the study population. Stool specimens having a single pathogen like rotavirus, ETEC, or Vibrio cholerae constituted the cases and stool specimens having no detectable common enteropathogens comprised the controls. Multinomial logistic regression analysis was done where control was the reference group.

Results

A total of 14 889 patients were enrolled, 6939 of whom were under-2 children, and 5245 (76%) constituted our study population. Among them 48% (n = 2532), 3% (n = 148) and 1% (n = 49) had rotavirus, ETEC, and Vibrio cholera, respectively. A control group (diarrhea without these 3 or Shigella, Salmonella, Aeromonas) accounted for 48% (n = 2516). In multinomial regression model, children with rotavirus (adjusted odds ratio [aOR], 1.36; 95% confidence interval [95% CI], 1.19-1.55) less often presented with dehydrating diarrhea compared to those with ETEC (aOR, 1.54; 95% CI, 1.05-2.26) and cholera (aOR, 2.25; 95% CI, 1.11-4.57). Rotavirus diarrhea was associated (aOR, 1.25; 95% CI, 1.07-1.46) with those who received antimicrobials prior to hospital admission and protectively associated with drinking tap water (aOR, 0.84; 95% CI, 0.73-0.95); however, ETEC diarrhea had protective association (aOR, 0.62; 95% CI, 0.43-0.92) with children who received antimicrobials prior to hospital admission and was associated with drinking tap water (aOR, 1.78; 95% CI, 1.19-2.66). Use of intravenous fluid was associated with cholera (aOR, 10.36; 95% CI, 4.85-22.16) and had protective association with rotavirus episodes (aOR, 0.64; 95% CI, 0.45-0.91).

Conclusions

Clinical presentations and host characteristics of rotavirus, ETEC, and Vibrio cholerae diarrhea differed from each other and the information may be helpful for clinicians for better understanding and proper management of these children.

A Phage Therapy Guide for Clinicians and Basic Scientists: Background and Highlighting Applications for Developing Countries

Approximately 10% of global health research is devoted to 90% of global disease burden (the so-called “10/90 Gap”) and it often neglects those diseases most prevalent in low-income countries. Antibiotic resistant bacterial infections are known to impact on healthcare, food security, and socio-economic fabric in the developing countries. With a global antibiotic resistance crisis currently reaching a critical level, the unmet needs in the developing countries are even more striking. The failure of traditional antimicrobials has led to renewed interest in century-old bacteriophage (phage) therapy in response to the urgent need to develop alternative therapies to treat infections. Phage therapy may have particular value in developing countries where relevant phages can be sourced and processed locally and efficiently, breaking specifically the economic barrier of access to expensive medicine. Hence this makes phage therapy an attractive and feasible option. In this review, we draw our respective clinical experience as well as phage therapy research and clinical trial, and discuss the ways in which phage therapy might reduce the burden of some of the most important bacterial infections in developing countries.