The Role of Vaccination,Antiorthopoxvirus Drug,and Social Cooperativity in a Mathematical Model of Smallpox Control

Abstract

Considerable effort has gone into making mathematical and computer models of smallpox spread and control measures, typically consisting of vaccination and quarantine. The orally available antiorthopoxvirus drug tecovirimat has recently completed Phase 2 clinical trials and shows promise as a smallpox control agent. We constructed 2 computer simulations to explore the use of tecovirimat in combination with vaccination and social cooperativity to control an outbreak. Two scenarios were considered: (1) a homogenously mixed, deterministic simulation of a single metropolitan area; and (2) a stochastic network of the 50 largest US metropolitan areas connected by commercial air traffic. Metropolitan-level mass vaccination coupled with drug treatment for all individuals who develop a fever considerably outperforms treating only those who develop smallpox's distinctive rash. Incorporating mass chemoprophylaxis represents another large improvement. More aggressive responses are more robust to low cooperation of the population with public health efforts and to faster disease spread. However, even with the most aggressive public health intervention, an attack that initially infects hundreds or thousands of individuals will need to be fought in multiple cities across the country.

Considerable effort has gone into making models of smallpox spread and control measures, typically consisting of vaccination and quarantine. The orally available antiorthopoxvirus drug tecovirimat has recently completed Phase 2 clinical trials and shows promise as a smallpox control agent. The authors constructed 2 computer simulations to explore the use of tecovirimat in combination with vaccination and social cooperativity to control an outbreak. Two scenarios were considered: (1) a homogenously mixed, deterministic simulation of a single metropolitan area; and (2) a stochastic network of the 50 largest US metropolitan areas connected by commercial air traffic. Metropolitan-level mass vaccination coupled with drug treatment for all individuals who develop a fever considerably outperforms treating only those who develop smallpox's distinctive rash. Incorporating mass chemoprophylaxis represents another large improvement. More aggressive responses are more robust to low cooperation of the population with public health efforts and to faster disease spread. However, even with the most aggressive public health intervention, an attack that initially infects hundreds or thousands of individuals will need to be fought in multiple cities across the country.