1. Basic Information
Disease Overview
- Cholera: Acute diarrheal illness caused by toxin-producing Vibrio cholerae, transmitted via contaminated food and water. Causes profuse watery diarrhea that can lead to fatal dehydration within hours if untreated. Case-fatality is <1% with prompt oral/IV rehydration, but up to 50% untreated. WHO estimates 1.3–4 million cases and 21,000–143,000 deaths annually worldwide, with major recent epidemics in Yemen, Haiti (historically), and parts of sub-Saharan Africa.
Vaccine Options
| Vaccine | Type | Schedule | Where Used |
|---|---|---|---|
| Vaxchora | Live attenuated (CVD 103-HgR), single oral dose | 1 dose, ≥10 days before travel; ages 2–64 | U.S. traveler use |
| Dukoral | Killed whole-cell + recombinant B subunit, oral | 2-dose series, 1–6 weeks apart | Canada, EU, other countries (not U.S.) |
| Shanchol / Euvichol | Killed bivalent whole-cell, oral | 2-dose series, 2 weeks apart | WHO-prequalified; used in mass campaigns/outbreak response via the global OCV stockpile in low- and middle-income countries |
Source: CDC Yellow Book; WHO Cholera vaccine position paper (2017).
Recommended For
- Adult travelers to areas with active cholera transmission, particularly those with limited access to safe food/water or working in humanitarian/healthcare settings.
- Populations in outbreak-affected or high-risk endemic areas, reached through WHO/UNICEF-coordinated mass vaccination campaigns using the global OCV stockpile (e.g., Yemen, Haiti, Mozambique, Democratic Republic of Congo).
2. Pre-Licensure Clinical Trial Data
Efficacy evidence differs by vaccine class: Vaxchora's licensure relied on a human challenge model, while Shanchol/Dukoral efficacy comes from large field trials in endemic settings.
| Vaccine | Efficacy Data | Evidence Strength |
|---|---|---|
| Vaxchora | ~90% efficacy against moderate-to-severe diarrhea in a controlled human challenge study at 10 days post-vaccination; ~80% at 3 months. No large real-world field effectiveness trial exists, given the rarity of cholera exposure in short-term U.S. travelers | Moderate |
| Shanchol / Dukoral (killed whole-cell) | ~65–76% efficacy over ~2 years in large field trials (India, Bangladesh); lower and shorter-lived protection in children under 5 | Strong |
Key Limitations
- Vaxchora's licensure is challenge-study-based, not a field efficacy trial: Real-world effectiveness data in actual travelers remain limited.
- Reduced protection in young children: Killed whole-cell vaccines (Shanchol/Dukoral) are notably less effective and shorter-acting in children under 5, the group at highest risk of severe cholera in endemic settings.
- Vaxchora is a live vaccine: Vaccine organism shedding in stool is possible for up to 7 days; direct contact with immunocompromised individuals should be avoided during this window.
3. Post-Licensure Safety Data
Post-Licensure Safety Monitoring
| Vaccine | Key Post-Licensure Finding |
|---|---|
| Vaxchora | Post-marketing surveillance since 2016 U.S. licensure has not identified an unusual safety signal; most reports are mild GI symptoms |
| Shanchol/Euvichol | Deployed in tens of millions of doses via WHO/Gavi-supported mass campaigns; pharmacovigilance in these campaigns has not identified serious safety concerns |
| Dukoral | Long track record in Canada/EU travel medicine; well tolerated, mild GI symptoms most common |
⚠ Critical Caveat
No cholera vaccine is 100% effective, and none is a substitute for safe food, water, and sanitation practices while traveling in or living in affected areas.
4. Documented Adverse Events — Evidence of Association
▶ Strong Evidence of Causal Association
- Mild GI symptoms (abdominal pain, nausea, diarrhea, vomiting): Most common reaction across all oral cholera vaccines, ~2–10%. Self-limited. Strong
- Fatigue/tiredness (Vaxchora): ~10–20% in trials. Self-limited. Strong
▶ Moderate or Preliminary Evidence
- Reduced efficacy/duration in children under 5 (killed whole-cell vaccines): Consistently observed across field trials, though the underlying immunologic reasons are not fully characterized. Limited mechanistic understanding
5. Disease Prevention Benefits
Outbreak Response Impact
| Setting | Outcome |
|---|---|
| Global OCV stockpile (established 2013) | Over 100 million doses of Shanchol/Euvichol deployed across dozens of outbreak-response and preventive campaigns worldwide through the WHO/UNICEF/IFRC/MSF-coordinated mechanism |
| Haiti post-earthquake outbreak response | OCV campaigns contributed to outbreak control alongside water/sanitation interventions |
| Yemen (ongoing epidemic, one of the largest in modern history) | Repeated OCV campaigns have been used to blunt transmission amid a humanitarian crisis with severely degraded water/sanitation infrastructure |
Source: WHO Global Task Force on Cholera Control; Gavi OCV stockpile reports.
6. Evidence Summary
Oral cholera vaccines provide moderate, time-limited protection and have become an important outbreak-response and traveler-protection tool alongside water, sanitation, and hygiene interventions. Efficacy is lower and shorter-lived in young children, the group most vulnerable to severe cholera, which remains an active area of vaccine development. All currently available vaccines are well tolerated, with mild self-limited GI symptoms being the dominant reported reaction.
| Domain | Evidence Grade | Key Finding |
|---|---|---|
| Vaxchora efficacy (challenge study) | Moderate | ~90% at 10 days, ~80% at 3 months |
| Shanchol/Dukoral field efficacy | Strong | ~65–76% over ~2 years, lower in children <5 |
| Reactogenicity | Strong | Mild, self-limited GI symptoms predominate |
| Outbreak-response impact | Strong | 100M+ doses deployed via global OCV stockpile |
7. Key References
- WHO. Cholera vaccines: WHO position paper. Wkly Epidemiol Rec. 2017;92(34):477–498.
- CDC. Cholera. CDC Yellow Book, Travelers’ Health. cdc.gov/yellowbook
- Chen WH, et al. Single-dose live oral cholera vaccine CVD 103-HgR protects against human challenge with Vibrio cholerae O1. Clin Infect Dis. 2016;62(11):1329–1335.
- Bi Q, et al. Protection against cholera from killed whole-cell oral cholera vaccines: a systematic review and meta-analysis. Lancet Infect Dis. 2017;17(10):1080–1088.
- WHO. Global Task Force on Cholera Control — OCV Stockpile. who.int