diff --git a/src/covid19_DTM/models/ODE_models.py b/src/covid19_DTM/models/ODE_models.py
index 6eefc62f..7cab0703 100644
--- a/src/covid19_DTM/models/ODE_models.py
+++ b/src/covid19_DTM/models/ODE_models.py
@@ -405,7 +405,7 @@ def integrate(t, S, E, I, A, M_R, M_H, C_R, C_D, C_icurec, ICU_R, ICU_D, R, D, M
         # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
         # Convert the number of infections to float and then copy to guarantee the array is contiguous for numba performance
-        dS_work = np.rint(np.nan_to_num(redistribute_infections(S, dS_work, place_eff), nan=0.0))
+        dS_work = np.rint(np.nan_to_num(redistribute_infections(S_post_vacc, dS_work.astype(float).copy(), place_eff), nan=0.0))
 
         ############################
         ## Compute system of ODEs ##