Predicting the impact of asymptomatic transmission, non-pharmaceutical intervention and testing on the spread of COVID19 COVID19

Ira B Schwartz; James H Kaufman; Kun Hu; Simone Bianco

With the hypothesis that social distancing reduces transmission by 25% and considering a 25% fraction of asymptomatic infectious, it is possible to see a two-fold reduction in the peak proportion of infected ( Figure 1 ). If control is released before the epidemic peak, at t = 0.28 years, the model predicts a strong resurgence of the disease, with no flattening and an infectious fraction almost reaching the uncontrolled epidemic. Of course, while a delay in the peak is observed, which may buy the health care system time to respond, the reduction in the number of total infectious is marginal. When NPI is removed at the epidemic peak (figure 1(b)), a secondary peak is observed, showing an increase in total number of infected. Lastly, when control is released after the peak (at a late stage of epidemic shown in figure 1(c)), for t ≈ 0.5 years, we observe the emergence of a kink in the descending part of the curve, but not a full fledged resurgence of the disease. The outbreak has a very different shape when infectious include a large proportion of asymptomatic individuals (Figure 2 ). In this case, early release of intervention causes a dramatic resurgence of the total infections, even for stronger control and at a late stage of the epidemic.