A Phase 2 interventional study of Azithromycin and Placebo in Cholera, sponsored by Massachusetts General Hospital. Completed at 1 site in Bangladesh. Open to participants aged 1 Year to 15 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-07.
Sponsored by Massachusetts General Hospital · Phase 2, Interventional, and Prevention
This study aims to determine whether single-dose azithromycin is effective in preventing cholera in children who are at extremely high risk of infection. The study will also determine the effect of this intervention on the development of antibiotic resistant bacteria. The results will inform future strategies to prevent cholera in children, and improve overall understanding of the impact of azithromycin on antibiotic resistance.
Vibrio cholerae causes 3 million cases of cholera and 100,000 deaths annually. An ongoing epidemic in Yemen has caused 1.7 million cases of cholera, with 58% of cholera-related deaths occurring in children. The World Health Organization (WHO) has targeted the elimination of cholera transmission by the year 2030, but the increasing burden of cholera suggests that more effective approaches are needed to prevent the disease. Access to safe water and sanitation and the use of oral cholera vaccines (OCV) are central to the WHO-proposed approach, but children remain particularly vulnerable. Children are at the highest risk of severe disease, and current cholera vaccines are ineffective in young children. In addition, natural disasters and human conflict often delay vaccination and other large-scale interventions.
Effective antibiotics reduce the volume and duration of diarrhea in cholera by over 50% and bacterial shedding by 80%. They are recommended for the treatment of moderate to severe cholera. Due to limited data, there are no standards for the use of antibiotic prophylaxis for cholera, resulting in widely varied clinical practices and the frequent use of antibiotics with unproven efficacy. For this reason, the WHO Global Task Force on Cholera Control has prioritized research in this area, suggesting that further use of prophylactic antibiotics for cholera should be stopped until prospective studies designed to measure the effectiveness of antibiotic prophylaxis and its impact on antibiotic resistance can be conducted. This study will address these two knowledge gaps. This study will determine whether a single dose of azithromycin is effective in preventing V. cholerae infection in children, and evaluate the impact of its administration on antibiotic resistance in the gut. This study focuses on children because current OCVs are ineffective in young children and because children are at the highest risk of infection and mortality from cholera. While single-dose azithromycin is a preferred treatment for cholera, it has never been studied as prophylaxis. Azithromycin has also been shown to be safe and beneficial in other recent chemoprophylaxis studies in children.
This is a double-blinded cluster randomized clinical trial of single-dose azithromycin to prevent cholera in children who are household contacts of a patient with cholera in Dhaka, Bangladesh. 920 children ages 1-15 years from 400 households in Dhaka, Bangladesh, who have shared cooking facilities for the prior three days with a household member with moderate to severe V. cholerae O1 infection, can participate in this study.
83 studies on the registry are indexed under Cholera; 16 are open to participants now.
This study's enrollment of 2,475 is above the median of 262 across 72 interventional studies indexed under Cholera.
Browse Cholera studies →Massachusetts General Hospital is the lead sponsor of 2,586 studies on the registry; 447 are open to participants now.
Of its 222 completed or terminated interventional studies of FDA-regulated products, 168 (76%) have results posted.
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Exclusion criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Enrolled children in a household randomized to the experimental group will receive a single weight-based dose of azithromycin administered by a trained study nurse within 12 hours of a member of their household testing positive for cholera. They will then complete 9 follow-up study visits in their home, during which rectal swabs and/or stool samples will be collected.
Drug: Azithromycin
Enrolled children in a household randomized to the placebo arm will receive a single dose of non-antibiotic placebo during their first study visit, which will occur within 12 hours of a member of their household testing positive for cholera. Like the participants in the intervention arm, they will complete 9 follow-up study visits in their home, during which rectal swabs and/or stool samples will be collected.
Biological: Placebo
Enrolled children in the intervention arm of this study will receive a single weight-based dose of azithromycin (20 mg/kg, to a maximum dose of 1 gram) administered by a trained study nurse within 12 hours of a member of their household testing positive for cholera.
Enrolled children in the placebo arm of this study will receive a single dose of non-antibiotic placebo administered by a trained study nurse within 12 hours of a member of their household testing positive for cholera.
Rate of V. Cholerae Infection in Household Contacts of Cholera Index Cases
The presence of V. cholerae O1 will be determined via the culturing of specimens collected via rectal swab sampling. Rectal swab acquisition will begin on the day of azithromycin administration and repeat on days 2, 3, 5, 6, and 7 following the intervention.
Time frame: 1 week
Participants were recruited from households of index patients with culture-confirmed cholera in Dhaka, Bangladesh. Eligible participants were household child contacts 1 to 15 years of age.
| Milestone | Azithromycin | Placebo |
|---|---|---|
| Started | 314 | 313 |
| Completed | 314 | 313 |
| Not completed | 0 | 0 |
The presence of V. cholerae O1 will be determined via the culturing of specimens collected via rectal swab sampling. Rectal swab acquisition will begin on the day of azithromycin administration and repeat on days 2, 3, 5, 6, and 7 following the intervention.
| Participants | Azithromycin | Placebo |
|---|---|---|
| Culture positive, ITT | 27 | 67 |
| Culture negative, ITT | 287 | 246 |
Collected over 6 months. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Azithromycin Group | 0/314 (0%) | 0/314 (0%) | 0/314 (0%) |
| Non-antibiotic Placebo Group | 0/313 (0%) | 1/313 (0.3%) | 0/313 (0%) |
| Event | Azithromycin Group | Non-antibiotic Placebo Group |
|---|---|---|
| HospitalizationInfections and infestations | 0/314 | 1/313 |
Only household contacts assigned to an intervention - not screened and index patients
| Age, Categorical(Participants) | Azithromycin | Placebo | Total |
|---|---|---|---|
| <=18 years | 314 | 313 | 627 |
| Between 18 and 65 years | 0 | 0 | 0 |
| >=65 years | 0 | 0 | 0 |
| Sex: Female, Male(Participants) | Azithromycin | Placebo | Total |
|---|---|---|---|
| Female | 146 | 158 | 304 |
| Male | 168 | 155 | 323 |
| Race (NIH/OMB)(Participants) | Azithromycin | Placebo | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 314 | 313 | 627 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 0 | 0 | 0 |
| White | 0 | 0 | 0 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Region of Enrollment(Participants) | Azithromycin | Placebo | Total |
|---|---|---|---|
| Bangladesh | 314 | 313 | 627 |
| Participants Assigned an Intervention(Participants) | Azithromycin | Placebo | Total |
|---|---|---|---|
| Count of participants | 314 | 313 | 627 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Oct 2021 to primary completion in May 2025, 43 months.
Results were first posted in Aug 2026, 1 year 2 months after primary completion.
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Studies of the drug tested here: Azithromycin
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