Centre for Data Science, Coventry University, UK; School of Computing, Electronics and Mathematics, Coventry University, UK.
Ministry of Health and Child Care, Harare, Zimbabwe.
Int J Infect Dis. 2020 Jul;96:222-227. doi: 10.1016/j.ijid.2020.03.077. Epub 2020 May 1.
In 2018, Zimbabwe declared another major cholera outbreak a decade after recording one of the worst cholera outbreaks in Africa.
A mathematical model for cholera was used to estimate the magnitude of the cholera outbreak and vaccination coverage using cholera cases reported data. A Markov chain Monte Carlo method based on a Bayesian framework was used to fit the model in order to estimate the basic reproductive number and required vaccination coverage for cholera control.
The results showed that the outbreak had a basic reproductive number of 1.82 (95% credible interval [CrI] 1.53-2.11) and required vaccination coverage of at least 58% (95% Crl 45-68%) to be contained using an oral cholera vaccine of 78% efficacy. Sensitivity analysis demonstrated that a vaccine with at least 55% efficacy was sufficient to contain the outbreak but at higher coverage of 75% (95% Crl 58-88%). However, high-efficacy vaccines would greatly reduce the required coverage, with 100% efficacy vaccine reducing coverage to 45% (95% Crl 35-53%).
These findings reinforce the crucial need for oral cholera vaccines to control cholera in Zimbabwe, considering that the decay of water reticulation and sewerage infrastructure is unlikely to be effectively addressed in the coming years.
2018 年，津巴布韦在记录了非洲最严重的霍乱疫情之一的十年后，再次宣布发生大规模霍乱疫情。
利用霍乱数学模型，根据报告的霍乱病例数据，估计霍乱疫情的严重程度和疫苗接种覆盖率。采用基于贝叶斯框架的马尔可夫链蒙特卡罗方法对模型进行拟合，以估计基本繁殖数和控制霍乱所需的疫苗接种覆盖率。
结果表明，此次疫情的基本繁殖数为 1.82（95%可信区间[CrI] 1.53-2.11），需要至少 58%（95%CrI 45-68%）的疫苗接种覆盖率才能控制疫情，所使用的口服霍乱疫苗的效力为 78%。敏感性分析表明，效力至少为 55%的疫苗足以控制疫情，但覆盖率需达到 75%（95%CrI 58-88%）。然而，高效力疫苗将大大降低所需的覆盖率，效力为 100%的疫苗将覆盖率降低至 45%（95%CrI 35-53%）。
这些发现强调了在津巴布韦需要使用口服霍乱疫苗来控制霍乱疫情，因为在未来几年，供水和污水基础设施的衰退不太可能得到有效解决。
