Transmission Dynamics of Enteric Diseases

Professor Pitzer’s research focuses on mathematical modeling of the transmission dynamics of enteric and imperfectly immunizing infections. She studies how interventions such as vaccination, improved treatment of cases, and improvements in sanitation affect disease transmission at the population level. She collaborates with individuals at the US Centers for Disease Control and Prevention (CDC), National Institutes of Health/Fogarty International Center (NIH/FIC), and Oxford University Clinical Research Unit (OUCRU) in Viet Nam, as well as with field researchers in India and Malawi. After receiving her Sc.D. in Epidemiology from Harvard School of Public Health, Dr. Pitzer did her postdoctoral fellowship with Bryan Grenfell at Penn State and Princeton University and the Research and Policy for Infectious Disease Dynamics (RAPIDD) program of the Department of Homeland Security and NIH/FIC before coming to Yale School of Public Health.

Projects

Projects

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Rotavirus transmission dynamics and potential impact of vaccination in developing countries

We are using mathematical models to understand patterns of incidence and potential "herd immunity" effects as rotavirus vaccination begins to be rolled out in developing countries.

vaccine

Understanding variation in rotavirus vaccine efficacy and waning of vaccine-induced immunity

Rotavirus vaccines exhibited considerably lower efficacy during clinical trials conducted in developing countries compared to developed countries. We are using mathematical models to explore potential explanations for this reduced efficacy.

typhoid cartoon crop

Historical analysis of typhoid fever in US cities

Cities across the United States exhibited different timing in terms of the decline in typhoid mortality during the late 19th and early 20th centuries, and also exhibited very different patterns of seasonality that did not follow a clear geographic pattern.

Typhoid conditions

Controlling Endemic Typhoid Fever

We are using mathematical models to evaluate the feasibility and impact of different methods of typhoid control, including vaccination, improved treatment strategies, and investment in clean water and sanitation.

Publications

Thompson CN, Kama M, Acharya S, Bera U, Clemens J, Crump JA, Dawainavesi A, Dougan G, Edmunds WJ, Fox K, Jenkins K, Khan MI, Koroivueta J, Levine MM, Martin LB, Nilles E, Pitzer VE, Singh S, Raiwalu RV, Baker S and Mulholland K: Typhoid fever in Fiji: a reversible plague? Trop Med Int Health. 2014 Oct;19 (10) :1284-92. Epub 2014 Jul 25. PMID: 25066005


Pitzer VE, Bowles CC, Baker S, Kang G, Balaji V, Farrar JJ and Grenfell BT: Predicting the impact of vaccination on the transmission dynamics of typhoid in South Asia: a mathematical modeling study. PLoS Negl Trop Dis. 2014;8 (1) :e2642. Epub 2014 Jan 9. PMID: 24416466

Patel MM, Pitzer VE, Alonso WJ, Vera D, Lopman B, Tate J, Viboud C and Parashar UD: Global seasonality of rotavirus disease. Pediatr Infect Dis J. 2013 Apr;32 (4) :e134-47. PMID: 23190782

Pitzer VE, Burgner D, Viboud C, Simonsen L, Andreasen V, Steiner CA and Lipsitch M: Modelling seasonal variations in the age and incidence of Kawasaki disease to explore possible infectious aetiologies. Proc Biol Sci. 2012 Jul 22;279 (1739) :2736-43. Epub 2012 Mar 7. PMID: 22398170


Pitzer VE and Basta NE: Linking data and models: the importance of statistical analyses to inform models for the transmission dynamics of infections. Epidemiology. 2012 Jul;23 (4) :520-2. PMID: 22659545


Atkins KE, Shim E, Pitzer VE and Galvani AP: Impact of rotavirus vaccination on epidemiological dynamics in England and Wales. Vaccine. 2012 Jan 11;30 (3) :552-64. Epub 2011 Nov 28. PMID: 22133508


Pitzer VE, Atkins KE, de Blasio BF, Van Effelterre T, Atchison CJ, Harris JP, Shim E, Galvani AP, Edmunds WJ, Viboud C, Patel MM, Grenfell BT, Parashar UD and Lopman BA: Direct and indirect effects of rotavirus vaccination: comparing predictions from transmission dynamic models. PLoS One. 2012;7 (8) :e42320. Epub 2012 Aug 13. PMID: 22912699


Lopman BA, Pitzer VE, Sarkar R, Gladstone B, Patel M, Glasser J, Gambhir M, Atchison C, Grenfell BT, Edmunds WJ, Kang G and Parashar UD: Understanding reduced rotavirus vaccine efficacy in low socio-economic settings. PLoS One. 2012;7 (8) :e41720. Epub 2012 Aug 6. PMID: 22879893

Pitzer VE, Patel MM, Lopman BA, Viboud C, Parashar UD and Grenfell BT: Modeling rotavirus strain dynamics in developed countries to understand the potential impact of vaccination on genotype distributions. Proc Natl Acad Sci U S A. 2011 Nov 29;108 (48) :19353-8. Epub 2011 Nov 14. PMID: 22084114


Pitzer VE, Viboud C, Lopman BA, Patel MM, Parashar UD and Grenfell BT: Influence of birth rates and transmission rates on the global seasonality of rotavirus incidence. J R Soc Interface. 2011 Nov 7;8 (64) :1584-93. Epub 2011 Apr 20. PMID: 21508015

Shaman J, Pitzer VE, Viboud C, Grenfell BT and Lipsitch M: Absolute humidity and the seasonal onset of influenza in the continental United States. PLoS Biol. 2010 Feb 23;8 (2) :e1000316. Epub 2010 Feb 23. PMID: 20186267

Lloyd-Smith JO, George D, Pepin KM, Pitzer VE, Pulliam JR, Dobson AP, Hudson PJ and Grenfell BT: Epidemic dynamics at the human-animal interface. Science. 2009 Dec 4;326 (5958) :1362-7. PMID: 19965751


Pitzer VE and Lipsitch M: Exploring the relationship between incidence and the average age of infection during seasonal epidemics. J Theor Biol. 2009 Sep 21;260 (2) :175-85. Epub 2009 Jun 13. PMID: 19527734


Pitzer VE, Viboud C, Simonsen L, Steiner C, Panozzo CA, Alonso WJ, Miller MA, Glass RI, Glasser JW, Parashar UD and Grenfell BT: Demographic variability, vaccination, and the spatiotemporal dynamics of rotavirus epidemics. Science. 2009 Jul 17;325 (5938) :290-4. PMID: 19608910

Pitzer VE, Leung GM and Lipsitch M: Estimating variability in the transmission of severe acute respiratory syndrome to household contacts in Hong Kong, China. Am J Epidemiol. 2007 Aug 1;166 (3) :355-63. Epub 2007 May 10. PMID: 17493952