Principal Investigators: Julio Ramirez, MD; Ruth Carrico PhD DNP
Co-Investigators: Ronika Alexander-Parish; Joann Zamparo, MPH

The UAD2 study, created in partnership with Pfizer, is designed to monitor the changing epidemiology of community-acquired pneumonia (CAP) and the current Streptococcus pneumoniae (S. pneumoniae) serogroups causing pneumonia in adults in the United States. Led by Dr. Julio Ramirez, former Chief of Infectious Diseases at the University of Louisville, the UAD2 study is a multi-hospital, active surveillance study to generate consistent and comparable population-based incidence in the inpatient setting.


CAP is an infection of the lung parenchyma that develops in persons outside of a healthcare facility and is associated with significant morbidity and mortality. The original UAD study from 2014 helped to understand the burden of community-acquired pneumonia (CAP) and the impact of S. pneumoniae as the pathogen of consequence. Results from the study were revealing, and prompted interest for further research:


  • Although we recognized that CAP is the leading cause of infectious disease-related death in the US, this study showed that the burden of CAP is much greater than any study has previously recognized.

  • Approximately 1 in 3 patients hospitalized with CAP died within 1 year.

  • The impact of pneumococcal vaccination was also part of the study. Those results demonstrated a 73% vaccine efficacy when the serotypes causing pneumonia matched those in the vaccine.

  • A related study activity also looked at the impact of antiviral treatment for patients admitted to the hospital with influenza.


Recognizing the current assessment of the incidence, epidemiology, and clinical outcomes of patients hospitalized with CAP is important to guide appropriate allocation of resources for prevention, management, and research, before hospitalization, during hospitalization, and after discharge.