Research

Our research interests include the use of molecular epidemiology to characterize the spread and persistence of viral infections, the study of the intersection of chronic disease and infection morbidity, and the evaluation of vaccination to reduce the burden of respiratory infections. We also have an interest in hospital epidemiology and infection prevention, including studies of multidrug resistant organisms and environmental decontamination.

Some of our current research topics are listed below:

Epidemiology of Viral Respiratory Disease in Vulnerable Individuals and Effective Interventions. Despite the availability and general acceptability of treatment and vaccines (a), influenza continues to cause substantial morbidity and mortality each year. We are working to further our understanding of the populations who are impacted most by influenza infection, particularly individuals with chronic comorbidities and immunosuppression. This work has been critical to our current efforts to define the effectiveness of influenza vaccine in preventing influenza-associated hospitalization. As a Co-PI for the UM Influenza Research Group, I continue to be involved in the ongoing CDC-funded US Flu Vaccine Effectiveness Network, a critical initiative to conduct influenza surveillance, provide timely vaccine effectiveness estimates, and to identify circulating strains to inform future vaccine formulations.

Viral Respiratory Infections are comprised of a Multi-pathogen, Dynamic System of Viruses. The identification of multiple pathogens in clinical settings is increasing with the advent of new molecular testing strategies and the discovery and characterization of novel viral subtypes. We have conducted a number of studies focused on the epidemiology and severity of viral coinfections. We have found that multiple viruses were frequent, present in 46% of childcare attendees, and that children with multiple virus illnesses had reduced severity of disease, both when considering hospitalized children and children in the community. The distribution of co-detected viruses varied greatly from week-to-week within individual illnesses. This work has demonstrated the importance of considering the range of viral etiologies and the use of repeated specimen collection when conducting epidemiologic studies.

Human Bocavirus is a Remarkably Persistent Respiratory Virus. My graduate work sparked my interest in studying viruses newly detected through molecular techniques, which has led to my current research on human bocavirus 1, a respiratory virus frequently found in conjunction with other viruses. The detection of HBoV-1 is commonly included in studies of respiratory virus epidemiology, however the clinical relevance of detection of human bocavirus-1 DNA in children has been debated. This is largely due to a high prevalence of HBoV-1 detection in asymptomatic children and the fact that HBoV-1 is often identified concurrently with other respiratory viruses known to cause acute illness. Our work has established the role of bocavirus as a persistent respiratory virus that cannot be fully characterized using cross-sectional convenience sampling.

Chronic Comorbidities Impact Susceptibility and Severity of Infection. It is imperative that epidemiologic studies of infection in individuals admitted for inpatient care conduct rigorous analyses of patient comorbidities and underlying conditions. To this end, my research group is conducting studies to identify patient-level factors that increase susceptibility to infection or severe disease and are applicable to a hospitalized patient population. We have extended our investigations of comorbidities in hospitalized individuals to the development and ongoing optimization of clinical scoring systems to identify patients at high risk of multidrug resistant infection at hospital admission. Finally, we are actively investigating the impact of patient obesity on respiratory infection severity, having found that hospitalized individuals with obesity have significantly increased lower pulmonary manifestations, inpatient admissions, and lengthy hospital stays.

Pathogen Sequencing as a Tool to Understand Person-to-Person Transmission. Determination of transmission events, critical to understanding vaccine and treatment effectiveness, is complicated by challenges in distinguishing between infections from epidemiologically linked close contacts and coincidental infections from the larger community. My laboratory has significantly contributed to our understanding of pathogen transmission through our application of sequence-based methods to standard epidemiologic investigations of transmission. Our work has included the development and/or application of molecular assays to identify transmission events and clonal patterns and to differentiate between persistent infection and reinfection events.