Field trial of oral cholera vaccines in Bangladesh

Area of Science:

• * Infectious Diseases
• * Vaccinology
• * Public Health

Background:

• * Cholera remains a significant public health threat, particularly in regions with limited access to clean water and sanitation.
• * Oral cholera vaccines (OCVs) offer a promising strategy for disease prevention and control.

Purpose of the Study:

• * To evaluate the protective efficacy of two oral cholera vaccines: B subunit killed whole-cell (BS-WC) and killed whole-cell (WC).
• * To assess vaccine performance across different age groups and cholera severities in a high-risk population.

Main Methods:

• * A randomized, double-blind, placebo-controlled trial involving 63,498 participants (children aged 2-15 years and women over 15 years) in Bangladesh.
• * Participants received three doses of either BS-WC, WC, or a placebo.
• * Surveillance for confirmed cholera cases was conducted for six months post-vaccination.

Main Results:

• * The BS-WC vaccine demonstrated a protective efficacy of 85% (p < 0.0001) with only 4 cholera cases observed in the vaccine group compared to 26 in the placebo group.
• * The WC vaccine showed a protective efficacy of 58% (p < 0.01) with 11 cholera cases in the vaccine group.
• * Vaccine efficacy was consistent across different age strata (2-10 years vs. >10 years) and cholera severities.

Conclusions:

• * The oral BS-WC cholera vaccine provides high and statistically significant protection against cholera.
• * The oral WC vaccine also offers significant protection, though to a lesser extent than BS-WC.
• * Both vaccines are effective in diverse age groups and against varying cholera severities, supporting their use in public health interventions.