Stemming cholera tides in Zimbabwe through mass vaccination

Area of Science:

• Epidemiology
• Mathematical Modeling
• Public Health

Background:

• Zimbabwe experienced a major cholera outbreak in 2018, following a severe epidemic a decade prior.
• Deteriorating water and sanitation infrastructure in Zimbabwe exacerbates cholera risks.

Purpose of the Study:

• To estimate the magnitude of the 2018 cholera outbreak in Zimbabwe.
• To determine the required vaccination coverage for effective cholera control using mathematical modeling.

Main Methods:

• A mathematical model was employed to analyze reported cholera cases.
• Bayesian inference with Markov Chain Monte Carlo (MCMC) methods was used to fit the model.
• Key epidemiological parameters, including the basic reproductive number (R0) and vaccination coverage, were estimated.

Main Results:

• The basic reproductive number (R0) for the outbreak was estimated at 1.82.
• A vaccination coverage of at least 58% with an oral cholera vaccine (OCV) of 78% efficacy is required for containment.
• Sensitivity analysis showed that 55% efficacy requires 75% coverage, while 100% efficacy reduces required coverage to 45%.

Conclusions:

• Oral cholera vaccines are crucial for controlling cholera in Zimbabwe.
• The findings underscore the importance of vaccination strategies given the persistent challenges with water and sanitation infrastructure.