Targeted adaptive isolation strategy for Covid-19 pandemic

Zoltan Neufeld; Hamid Khataee

According to Equation (3), reducing the loss in S V requires reducing the product µI total . While social distancing aims to reduce the total infected population by decreasing R 0 , this model helps to evaluate alternative or complementary measures targeting the reduction of parameter µ by isolating/shielding the vulnerable population from the infections. This could be achieved by clearly differentiated measures targeted to the high-risk group: restricting mobility, providing free homedelivery of food and medication, increased support addressing communication and healthcare needs, and providing separated living space where needed. Since the isolation strategy targets a subpopulation, a radical isolation is likely to be more effective than uniform social distancing, and at a smaller cost for the economy and for the general functioning of the society. Our model allows the comparison of general social distancing affecting both k and µ (represented by the diagonal arrow in Fig. 2(c) ) and targeted isolation affecting µ only (vertical arrow in Fig. 2(c) ). The overall fatality of the pandemic is primarily driven by the size of the infected vulnerable population, µI total . Depending on the epidemiological situation, the public response should be a mixture of the two efforts. For low values of R 0 , general social distancing is more effective and has the potential to suppress the epidemic. At higher R 0 values, however, the optimal public response should focus more heavily on isolation of the vulnerable population. With limited resources available, when the strategy is primarily based on drastic targeted isolation over a shorter time, the end result is a collectively immune population resistant to further infections ("herd immunity"). It is also apparent that the integral in Equation (3) can be reduced by decreasing µ in a timedependent manner. This can be achieved by monitoring the progression of the infection I(t) via statistically representative testing of different regions and cities, and intensifying/relaxing the isolation of the vulnerable population accordingly.