Cholera Susceptibility: Why Some People Get Sicker Than Others

Cholera (Vibrio cholerae O1/O139) infection outcomes range from asymptomatic to fatal. Susceptibility varies due to host, pathogen, and environmental factors.

Host Factors

• Blood Group O: 2× risk of severe cholera vs. other groups (mechanism unclear)
• Genetic Variants: CFTR, HLA, ABO, innate immunity genes affect severity
• Age: Children 2–9 yrs and elderly highest severity; adults often mild/asymptomatic
• Nutritional Status: Malnutrition → impaired immunity, worse outcomes; zinc/vitamin A deficiency increase risk
• Comorbidities: HIV, immunosuppression, achlorhydria (low stomach acid—major risk)
• Microbiome: Diversity protects; antibiotics increase susceptibility

Immunity

• Natural Infection: Confers ~3–10 years protection (serogroup-specific)
• Vaccination (OCV): Killed whole-cell (Shanchol, Euvichol) — 65% efficacy at 5 yrs; 2 doses
• Breastfeeding: IgA antibodies protect infants

Environmental/Behavioral Factors

• Water/Sanitation (WASH): Primary determinant of exposure dose
• Inoculum Size: Higher dose → shorter incubation, more severe
• Co-infections: Helminths, enteric pathogens worsen outcomes

Public Health Implications

Targeted vaccination (endemic areas, outbreaks, humanitarian crises), WASH infrastructure, nutrition programs, and rapid rehydration access (ORS) reduce population-level burden more than individual risk stratification.