Casey Zipfel

Infectious disease ecology • Network science • Computational epidemiology

Mobirise
Mobirise

ABOUT ME
I am a Ph.D. student in the Biology Department at Georgetown University. I work in the Bansal Lab, studying the interplay between human behavior and infectious disease ecology. I am specifically interested in infection-induced behavior change and childhood vaccination behavior in the United States.

Research

INFECTION-INDUCED BEHAVIOR CHANGE

When people become sick, they frequently stay home from school or work, changing their regular contact patterns, and their potential to transmit their infection. Models of epidemic spread generally ignore this ubiquitous behavior; network models usually use static networks based on the contact behavior of healthy individuals. Additionally, there are other complexities of infection-induced behavior change that are relevant to disease spread. Many people do not have access to paid sick days, and many do not adhere to public health recommendations to take sick days. Also, a sick child usually results in an adult remaining home as well. I am utilizing a data-driven approach to integrate these realistic behavior changes into infectious disease models. I utilized an exponential random graph model to generate large, empirically-based networks from a survey of human contact behavior. Then, I simulate epidemics on these networks including realistic behavior change by infected individuals. Lastly, I compare the behavior change models with seasonal influenza epidemics in the United States to quantify how incorrect our epidemic predictions are when we ignore behavior.
Mobirise

Infected nodes that change their behavior change the topology of their contact network. 

Mobirise

Behavior change (BC) decreases epidemic size, especially when access to paid sick days are unequally distributed. 

Mobirise

Behavior change (BC) delays the timing of epidemic peak, especially when access to paid sick days are unequally distributed.  

CHILDHOOD VACCINATION BEHAVIOR IN THE UNITED STATES

Vaccine hesitancy, the conscious decision to delay or refuse vaccination, is an increasing phenomenon in the United States. Vaccine hesitancy poses a clear barrier to covering the last mile in global disease eradication efforts for Vaccine Preventable Diseases, such as measles and polio. Individuals' attitudes towards vaccination are dynamic, but it is unclear what drives vaccination-related attitudes and behaviors in the United States. To address this, I aim to characterize vaccination behavior dynamics in the United States. I am utilizing a large insurance claims dataset to investigate the relationship between vaccination behaviors and several determinants of vaccine decision-making, like perceived risk of infection, perceived risk of vaccine-adverse events, attitudes towards vaccination, social norms, and state-specific vaccination policies. 
Mobirise

Vaccine hesitancy and refusal is heterogeneous across the United States. The data is normalized to account for population size and reporting in each county.
(White: no data, blue/purple: no-low vaccine refusal, yellow/green: high vaccine refusal). 

Mobirise

Vaccine hesitancy and refusal exhibits seasonal trends and are increasing over time in the United States. The data is normalized to account for seasonality in all-cause healthcare seeking behavior. 

Mobirise
Mobirise
Mobirise
Mobirise

CONTACT ME!

Email: cmz27@georgetown.edu

Twitter: @casey_zipfel