Risk Adjusted Non-Pharmaceutical Interventions for the Management of COVID-19 in South Africa

A global analysis of the impact of non-pharmaceutical interventions (NPIs) on the dynamics of the spread of the COVID-19 indicates that these can be classified using the stringency index proposed by the Oxford COVID-19 Government Response Tracker (OxCGRT) team. The world average for the coefficient that linearises the level of transmission with respect to the OxCGRT stringency index is α s = 0.01 ± 0.0017 (95% C.I.). The corresponding South African coefficient is α s = 0.0078 ± 0.00036 (95% C.I.), compatible with the world average. Here, we implement the stringency index for the recently announced 5-tier regulatory alert system. Predictions are made for the spread of the virus for each alert level. Assuming constant rates of recovery and mortality, it is essential to increase α s . For the system to remain sub-critical, the rate with which α s increases should outpace that of the decrease of the stringency index. Monitoring of α s becomes essential to controlling the post-lockdown phase. Data from the Gauteng province obtained in May 2020 has been used to re-calibrate the model, where α s was found increase by 20% with respect to the period before lockdown. Predictions for the province are made in this light.