A Latent Class Model to Estimate Vaccine Effectiveness

• Activity Number: 244
• Type: Contributed
• Date/Time: Monday, August 4, 2014 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Tracy Pondo*+ and Nong Shang
• Companies: CDC and CDC
• Keywords: latent class ; vaccine effectiveness

Abstract

We developed a latent class model to estimate the vaccine effectiveness for a vaccine with "all or none" protection. All or none protection describes vaccinations that provide full protection from disease to a proportion of the vaccinated population and no protection from disease to the remainder of the vaccinated. We had 10 years of data from the time period before vaccine introduction and data from the first 6 years when the vaccine was in use. Disease rates were declining before vaccine introduction and we were interested in distinguishing the impact of vaccine introduction from the continuous decrease in disease incidence rates that occurred throughout the 16 year study period. We used latent class methods to estimate the proportion of the vaccinated population that remained susceptible to disease. We also estimated vaccine effectiveness based on our results.