William Reidy, PhD, MPH

  • Assistant Professor of Epidemiology (in ICAP) at the Columbia University Medical Center
Profile Headshot


William Reidy is an epidemiologist whose focus at the Mailman School includes both implementation science research and supporting the global scale-up of HIV/AIDS prevention and medical care services.  Dr. Reidy has worked as an investigator or in a strategic information role on projects in numerous countries including Swaziland, Kenya, Myanmar, Tanzania, and South Africa.  His strategic information support of program scale-up has aimed to strengthen systems for provision of HIV medical care, prevention of mother-to-child transmission of HIV (PMTCT), HIV testing and counseling, and HIV prevention programs for key populations, including pre-exposure prophylaxis.  Dr. Reidy's research has examined the performance of HIV medical care and PMTCT models during scale-up and factors related to successful patient outcomes.      


Academic Appointments

  • Assistant Professor of Epidemiology (in ICAP) at the Columbia University Medical Center

Credentials & Experience

Education & Training

  • MPH, 2001 University of California, Los Angeles
  • PhD, 2008 University of Washington


Dr. Reidy aims to contribute to the global HIV/AIDS response, with a focus on optimizing HIV services.


Selected Publications

William Reidy, Miriam Rabkin, Maureen Syowai, Andrea Schaaf, and Wafaa M. El-Sadr. Patient-level and program-level monitoring and evaluation of differentiated service delivery for HIV: a pragmatic and parsimonious approach is needed. AIDS. 2018; 32(3):399-401.

Abby DiCarlo, Ruby Fayorsey, Masila Syengo, Duncan Chege, Martin Sirengo, William Reidy, Juliana Otieno, Jackton Omoto, Mark P Hawken, Elaine Abrams. Lay Health Worker Experiences Administering a Multi-level Combination Intervention to Improve PMTCT Retention. BMC Health Services Research. 2018; 18(17).

William Reidy, Mansi Agarwal, Duncan Chege, Matt Lamb, Mark Hawken, Irene Mukui, Elaine Abrams, and Elvin Geng. Retention in Care Among HIV-Infected Patients Receiving or Not Receiving Antiretroviral Therapy in Eastern Africa. Clinical Infectious Diseases. May 2016. doi:10.1093/cid/ciw302. PMCID: PMC4946022

Ruby Fayorsey, Duncan Chege, Chunhui Wang, William Reidy, Zachary Peters, Martin Sirengo, Masila Syengo, Mark Hawken, Elaine Abrams. Mother Infant Retention for Health (MIR4Health): Study Design, Adaptations, and Challenges with PMTCT Implementation Science Research. JAIDS. 2016;72(S2): S137-S144. PMID: 27355501.

William Reidy, Muhsin Sheriff, Chunhui Wang, Mark Hawken, Emily Koech, Batya Elul, Davies Kimagna, and Elaine Abrams for the Identifying Optimal Models of HIV Care in Africa: Kenya Consortium. Decentralization of HIV care and treatment services in Central Province, Kenya. JAIDS. 2014;67(1):e34-40.

Harriet Nuwagaba-Biribonwoha, Bonita Kilama , Gretchen Antelman, Khatib A, Annette Almeida, William Reidy, Gongo Ramadhani, Matthew Lamb, Redempta Mbatia, Elaine J Abrams. Reviewing progress: 7 year trends in characteristics of adults and children enrolled at HIV care and treatment clinics in the United Republic of Tanzania. BMC Public Health. 2013 Oct 27;13(1):1016.

William Reidy and Steven Goodreau. The role of commercial sex venues in the HIV epidemic among men who have sex with men in King County, WA. Epidemiology. 2010; 21(3):349-359.

William Reidy, Freya Spielberg, Robert Wood, Diane Binson, William Woods and Gary Goldbaum. Risk associated with gay bathhouses and sex clubs: Findings from 2 Seattle surveys of factors related to HIV and sexually transmitted infections. American Journal of Public Health. 2009; 99(S1): S165-S172.

Freya Spielberg, Anne Kurth, William Reidy, Teka McKnight, Wame Dikobe and Charles Wilson. Iterative Evaluation in a Mobile Counseling and Testing Program to Reach People of Color at Risk for HIV - New Strategies Improve Program Acceptability, Effectiveness, and Evaluation Capabilities. AIDS Education and Prevention. 2011; 23(3) S110-116. PMCID: PMC5108299

Global Health Activities

Safe Generations - Plus: Safe Generations-Plus is implementation science study funded by the National Institutes of Health which aims to understand how to improve retention in care and treatment services for HIV-positive pregnant women and their babies in Swaziland. In this study we are assessing outcomes of patients who were lost to follow-up from care under a new approach for prevention of mother-to-child (PMTCT) called Option B+, where all HIV positive pregnant women initiate lifelong antiretroviral therapy (ART) regardless of their health status. The goal is to understand the outcomes of patients who are lost to follow-up from care, and the reasons for disengagement from care in the context of Option B+ in order to inform efforts to improve retention in care and patient outcomes.