The effects of non-pharmaceutical interventions on SARS-CoV-2 transmission in different socioeconomic populations in Kuwait: a modeling study

Background: Aggressive non-pharmaceutical interventions (NPIs) may reduce transmission of SARS-CoV-2. The extent to which these interventions are successful in stopping the spread have not been characterized in countries with distinct socioeconomic groups. We compared the effects of a partial lockdown on disease transmission among Kuwaitis (P₁) and non-Kuwaitis (P₂) living in Kuwait. Methods: We fit a modified metapopulation SEIR transmission model to reported cases stratified by two groups to estimate the impact of a partial lockdown on the effective reproduction number (R_e). We estimated the basic reproduction number (R) for the transmission in each group and simulated the potential trajectories of an outbreak from the first recorded case of community transmission until 12 days after the partial lockdown. We estimated R_e values of both groups before and after the partial curfew, simulated the effect of these values on the epidemic curves and explored a range of cross-transmission scenarios. Results: We estimate R_e at 1·08 (95% CI: 1·00–1·26) for P₁ and 2·36 (2·03–2·71) for P₂. On March 22nd, R_e for P₁ and P₂ are estimated at 1·19 (1·04–1·34) and 1·75 (1·26–2·11) respectively. After the partial curfew had taken effect, R_e for P₁ dropped modestly to 1·05 (0·82–1·26) but almost doubled for P₂ to 2·89 (2·30–3·70). Our simulated epidemic trajectories show that the partial curfew measure greatly reduced and delayed the height of the peak in P₁, yet significantly elevated and hastened the peak in P₂. Modest cross-transmission between P₁ and P₂ greatly elevated the height of the peak in P₁ and brought it forward in time closer to the peak of P₂. Conclusion: Our results indicate and quantify how the same lockdown intervention can accentuate disease transmission in some subpopulations while potentially controlling it in others. Any such control may further become compromised in the presence of cross-transmission between subpopulations. Future interventions and policies need to be sensitive to socioeconomic and health disparities.