Estimating Disease Transmission Rates Using Susceptible-Infected-Recovered (SIR) Models

• Activity Number: 650
• Type: Contributed
• Date/Time: Thursday, August 8, 2013 : 8:30 AM to 10:20 AM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Long H. Ngo*+ and David S. Yassa and Sharon Wright and Baevin Carbery
• Companies: Harvard Medical School and Beth Israel Deaconess Med Center & Harvard Medical School and Beth Israel Deaconess Med Center & Harvard Medical School and Beth Israel Deaconess Medical Center
• Keywords: MRSA ; transmission rate ; Susceptible-Infected-Recovered Model ; differential equations ; compartmental models

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is known to be the most common cause of skin and soft tissue infections in the United States. Community-associated MRSA (CA-MRSA), initially associated with community-based disease and transmission, has quickly entered the hospital setting and is now a frequent cause of hospital-associated infections. Between the fall of 2008 and summer of 2010, an outbreak of CA-MRSA infections occurred at a large urban teaching hospital among post-partum women and newborns. An effort is underway to analyze the data to identify factors that were associated with infections and to estimate the disease transmission rate, taking into account infections among susceptible and infected subjects within and between post-partum woman-newborn clusters. We employ the stochastic epidemic Susceptible-Infected-Recovered (SIR) model which is a pharmacokinetic compartmental model with three compartments represented by three first-order ordinary differential equations. The transmission rate between the Susceptible and Infected compartments, a product of the average number of contacts and the probability of infection per contact, is the parameter of interest.