[BostonCard]

Testing and tracing doesn't have to be perfect, they just have to be good enough to reduce R(t) to below 1.  Suppose the baseline R0 is 2.5 (a reasonable estimate for COVID-19).  That means that absent any intervention, every infected patient transmits the infection to 2.5 other people.  You don't have to intercept all of those chains of transmission to keep the infection stable; you just have to intercept 1.5 of those transmission chains so that the R(t) gets down to 1, in which case each infected patient will infect only one other patient and the infection rate remains stable.  If you can drive R(t) to slightly below 1 the infection rate will decline over time.

BC

[BostonCard]

Testing and tracing doesn't have to be perfect, they just have to be good enough to reduce R(t) to below 1.  Suppose the baseline R0 is 2.5 (a reasonable estimate for COVID-19).  That means that absent any intervention, every infected patient transmits the infection to 2.5 other people.  You don't have to intercept all of those chains of transmission to keep the infection stable; you just have to intercept 1.5 of those transmission chains so that the R(t) gets down to 1, in which case each infected patient will infect only one other patient and the infection rate remains stable.  If you can drive R(t) to slightly below 1 the infection rate will decline over time.

BC