Getting to zero quickly in the 2019-nCov epidemic with vaccines or rapid testing

Chowell, Gerardo; Dhillon, Ranu; Srikrishna, Devabhaktuni

Any plan for stopping the ongoing 2019-nCov epidemic must be based on a quantitative understanding of the proportion of the at-risk population that needs to be protected by effective control measures in order for transmission to decline sufficiently and quickly enough for the epidemic to end. Using an SEIR-type transmission model, we contrasted two alternate strategies by modeling the proportion of the population that needs to be protected from infection by one-time vaccination (assuming 100% effectiveness) or by testing with isolation and treatment of individuals within six, 24, or 48 hours of symptom onset. If R is currently 2.2, vaccination at the herd immunity coverage of 55% would drive R just below 1, but transmission could persist for years. Over 80% of coverage is required to end the epidemic in 6 months with population-wide vaccination. The epidemic could be ended in just under a year if testing with isolation and treatment reached 80% of symptomatically infected patients within 24 hours of symptom onset (assuming 10% asymptomatic transmission). The epidemic could be ended in six months if testing with isolation and treatment reached 90% of symptomatic patients. If 90% of symptomatic patients could be tested within six hours of symptoms appearing, the epidemic could be ended in under four months.