Dynamical Regulations On Mobility and Vaccinations To Control Covid19 Spread

Using a system of time-dynamical equations, we investigate how daily mobility indices, such as homestay above the pre-Covid normal ( H% ; or H -forcing), and cumulative vaccinations ( V c %; or V -forcing) impact the net reproductive rate (R0) of COVID19 in ten island nations as a prototype, and then, extending it to 124 countries Worldwide. Our H - and V -forcing model of R0 could explain the new trends in 106 countries. The disease transmission can be controlled by forcing down R0 ( H, Vc ) 40% in 91% of countries with 0% vaccinated plus recovered, V p . The required critical H% decreases with increasing V p %, dropping it down to 20% with 25% V p , and further down to 8% with 50% V p . However, the regulations on H% are context-dependent and country-specific. Our Model is useful in forecasting and controlling the disease spread when the effectiveness of the vaccines is a concern due to new variants, and/or delays in vaccination rollout programs.