MarkSimondsRiddleMDDrPH, FISTM

Preventive Medicine • Verdi, NV

Public Health & General Preventive Medicine

Director, Vaccines Clinical Research & Development Pfizer, Inc.

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Office
PO Box 1430
Verdi, NV 89439
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Education & Training

National Capital Consortium (USUHS)Residency, Public Health and General Preventive Medicine, 2000 - 2002
Tulane University School of MedicineClass of 1997

Certifications & Licensure

NV State Medical License 2019 - 2025
CA State Medical License 1998 - 2024
LA State Medical License 2000 - 2020
American Board of Preventive Medicine Public Health & General Preventive Medicine

Clinical Trials

Shigella Flexneri 2a Invaplex 50 Vaccine Dose Finding and Assessment of Protection Start of enrollment: 2007 May 01
Completed
Phase 1, Phase 2
Safety Study of Recombinant Vaccine to Prevent ETEC Diarrhea Start of enrollment: 2011 Jul 01
Completed
Phase 1
Trial Evaluating Ambulatory Treatment of Travelers' Diarrhea Start of enrollment: 2012 Sep 01
Terminated
Not Applicable
Safety Study of a Capsule-Conjugate Vaccine to Prevent Campylobacter-Caused Diarrhea Start of enrollment: 2014 Apr 21
Completed
Phase 1
Efficacy of Rifaximin in Preventing Campylobacteriosis Start of enrollment: 2014 Oct 01
Completed
Phase 2, Phase 3
Safety and Tolerability of a Bioconjugate Vaccine Against Shigella Flexneri 2a Start of enrollment: 2015 Feb 01
Completed
Phase 1
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Publications & Presentations

PubMed

2 citations
Reassessing potential economic value and health impact of effectivevaccines.
Riddle, M. S., William P Hausdorff, John D Anderson 4th, A Louis Bourgeois, Allison Clifford, Jessica A Fleming, Farzana Muhib, Clint Pecenka, Chloe Puett, Mark S Ridd...> ;Bulletin of the World Health Organization. 2024 Jan 1
1 citations
Gut microbiome and antibiotic resistance effects during travelers' diarrhea treatment and prevention.
Kevin S Blake, Drew J Schwartz, Srinand Paruthiyil, Bin Wang, Jie Ning, Sandra D Isidean, Daniel S Burns, Harris Whiteson, Tahaniyat Lalani, Jamie A Fraser, Patrick Co...> ;Mbio. 2024 Jan 16
4 citations
Vaccine value profile for norovirus.
George Armah, Ben A Lopman, Jan Vinjé, Miguel O'Ryan, Claudio F Lanata, Michelle Groome, Jared Ovitt, Caroline Marshall, Elizabeth Sajewski, Mark S Riddle> ;Vaccine. 2023 Nov 3
1 citations
A First in Human Clinical Trial Assessing the Safety and Immunogenicity of Two Intradermally Delivered EnterotoxigenicCFA/I Fimbrial Tip Adhesin Antigens with and with...
Ramiro L Gutiérrez, Chad K Porter, Milton Maciel Jr, Steven T Poole, Renee M Laird, Michelle Lane, George W Turiansky, Abel Jarell, Stephen J Savarino, Riddle, M. S., ...> ;Microorganisms. 2023 Nov 2
2 citations
Clinical and regulatory development strategies for Shigella vaccines intended for children younger than 5 years in low-income and middle-income countries.
Birgitte K Giersing, Richard Isbrucker, David C Kaslow, Marco Cavaleri, Norman Baylor, Diadié Maiga, Patricia B Pavlinac, Gagandeep Kang, Calman A MacLennan, Riddle, M...> ;The Lancet. Global Health. 2023 Nov 1
Advances on the forefront of travellers' diarrhoea.
Charles D Ericsson, Robert Steffen, Riddle, M. S., Mark S Riddle> ;Journal of Travel Medicine. 2023 Oct 31
1 citations
GMP manufacture of Shigella flexneri 2a Artificial Invaplex (Invaplex) and evaluation in a Phase 1 Open-label, dose escalating study administered intranasally to healt...
Christopher Duplessis, Kristen A Clarkson, K Ross Turbyfill, Ashley N Alcala, Ramiro Gutierrez, Tida Lee, Kristopher Paolino, Hailey P Weerts, Amanda Lynen, Edwin V Oa...> ;Vaccine. 2023 Oct 6
Serum antibody levels to SARS-CoV-2 receptor-binding domain (RBD) in convalescent patients and vaccinated individuals of northern Nevada.
Derrick Hau, Kathryn J Pflughoeft, Marcellene A Gates-Hollingsworth, Simranjit Kaur, Haydon J Hill, Jose Arias-Umana, Chelsea C Chung, Valerie L Smith, Sara A Healy, D...> ;Plos One. 2023 Jan 1
Diarrhea, Dysbiosis, Dysfunction, and the Disastrous Global Health Consequences: Piecing the Puzzle Together.
Steven A. Frese, Mark S. Riddle> ;The American Journal of Gastroenterology. 2021 Dec 1
15 citations
World Health Organization Expert Working Group: Recommendations for assessing morbidity associated with enteric pathogens.
Mateusz Hasso-Agopsowicz, Benjamin A. Lopman, Claudio F. Lanata, Elizabeth T. Rogawski McQuade, Gagandeep Kang, Holly J. Prudden, Ibrahim A Khalil, James A Platts-Mill...> ;Vaccine. 2021 Nov 24
10 citations
Critical needs in advancing Shigella vaccines for global health
Calman A. MacLennan, Kawsar R. Talaat, Robert W. Kaminski, Dani Cohen, Mark S. Riddle, Birgitte K. Giersing> ;The Journal of Infectious Diseases. 2021 Sep 24
6 citations
TaqMan Array Card testing of participant-collected stool smears to determine the pathogen-specific epidemiology of travellers’ diarrhoea†
Michele D. Tisdale, David R. Tribble, Indrani Mitra, Kalyani Telu, Huai-Ching Kuo, Jamie Fraser, Jie Liu, Eric R. Houpt, Mark S. Riddle, Drake H Tilley, Anjali Kunz, H...> ;Journal of Travel Medicine. 2021 Sep 7
3 citations
A disease severity scale for the evaluation of vaccine and other preventive or therapeutic interventions for travelers' diarrhea.
Nicole Maier, Mark S. Riddle, Ramiro L. Gutierrez, Jamie Fraser, Patrick Connor, David R. Tribble, Chad K. Porter> ;Journal of Travel Medicine. 2021 Sep 6
20 citations
Safety and immunogenicity of intramuscularly administered CS6 subunit vaccine with a modified heat-labile enterotoxin from enterotoxigenic Escherichia coli.
Tida Lee, Ramiro L. Gutierrez, Milton Maciel, Steven T. Poole, Kayla J. Testa, Stefanie Trop, Christopher A. Duplessis, Alison Lane, Mark S. Riddle, Melinda Hamer, Ash...> ;Vaccine. 2021 Aug 18
6 citations
Enteric Pathogens and Reactive Arthritis: Systematic Review and Meta-Analyses of Pathogen-Associated Reactive Arthritis.
Kristen Pogreba-Brown, Erika Austhof, Xin Tang, Mario Jesus Trejo, Ama Owusu-Dommey, Kylie Boyd, Alexandra Armstrong, Kenzie Schaefer, Michael C. Bazaco, Michael Batz,...> ;Foodborne Pathogens and Disease. 2021 Jul 13
3 citations
A prospective observational study describing severity of acquired diarrhea among U.S. military and Western travelers participating in the Global Travelers' Diarrhea St...
Hayley R. Ashbaugh, June M. Early, Myles E. Johnson, Mark P. Simons, Paul C. F. Graf, Mark S. Riddle, Brett E. Swierczewski> ;Travel Medicine and Infectious Disease. 2021 Jul 13
6 citations
What's new in travelers' diarrhea: Updates on epidemiology, diagnostics, treatment, and long-term consequences.
Audrey A Adler, Hailee R Ciccotti, Spencer J H Trivitt, Roland C J Watson, Mark S. Riddle> ;Journal of Travel Medicine. 2021 Jul 6
12 citations
Global diarrhoea-associated mortality estimates and models in children: Recommendations for dataset and study selection.
Egle Butkeviciute, Holly J. Prudden, Mark Jit, Pete Smith, Gagandeep Kang, Mark S. Riddle, Benjamin A. Lopman, Virginia E. Pitzer, Claudio F. Lanata, James A Platts-Mi...> ;Vaccine. 2021 Jun 13
2 citations
Fecal Microbiota Functional Gene Effects Related to Single-Dose Antibiotic Treatment of Travelers' Diarrhea.
Ryan C. Johnson, Joy D. Van Nostrand, Michele D. Tisdale, Brett E. Swierczewski, Mark P. Simons, Patrick Connor, Jamie Fraser, Angela R. Melton-Celsa, David R. Tribble...> ;Open Forum Infectious Diseases. 2021 May 28
1 citations
The traveller and antimicrobial resistance: what's new and where are we headed?
Mark S. Riddle, Charles D. Ericsson, Robert Steffen> ;Journal of Travel Medicine. 2021 Apr 14
29 citations
Immune response characterization in a human challenge study with a Shigella flexneri 2a bioconjugate vaccine.
Kristen A. Clarkson, Kawsar R. Talaat, Cristina Alaimo, Patricia Martin, A. Louis Bourgeois, Anita M. Dreyer, Chad K. Porter, Subhra Chakraborty, Jessica Brubaker, Dan...> ;Ebiomedicine. 2021 Apr 1
48 citations
Human challenge study with a Shigella bioconjugate vaccine: Analyses of clinical efficacy and correlate of protection
Kawsar R. Talaat, Cristina Alaimo, Patricia Martin, A. Louis Bourgeois, Anita M. Dreyer, Robert W. Kaminski, Chad K. Porter, Subhra Chakraborty, Kristen A. Clarkson, J...> ;Ebiomedicine. 2021 Apr 1
1 citations
The interrelationship between water access, exclusive breastfeeding and diarrhea in children: a cross-sectional assessment across 19 African countries.
Paschal Awingura Apanga, Ann M. Weber, Lyndsey A. Darrow, Mark S. Riddle, Wei-Chen Tung, Yan Liu, Joshua V. Garn> ;Journal of Global Health. 2021 Mar 27
7 citations
Using COVID-19 cycle threshold and other lab values as predictors of hospitalization need.
Ramamahesh Seeni, Mark S. Riddle, Charles Krasner, Sara Ashraf, Faisal Siddiqui, Tarek R. Firzli> ;Journal of Medical Virology. 2021 Feb 2
5 citations
Refinement of the CS6-expressing enterotoxigenic Escherichia coli strain B7A human challenge model: A randomized trial.
Kawsar R. Talaat, Chad K. Porter, Kayla Jaep, Christopher A. Duplessis, Ramiro L. Gutierrez, Milton Maciel, Brittany Adjoodani, Brittany Feijoo, Subhra Chakraborty, Je...> ;Plos One. 2020 Dec 2
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Journal Articles

Enterotoxigenic E. Coli Virulence Gene Regulation in Human Infections
Kawsar R Talaat, Mark S Riddle, Stephen J Savarino, Proceedings of the National Academy of Sciences
Rotavirus Vaccination and the Global Burden of Rotavirus Diarrhea Among Children Younger Than 5 Years
Beth D Kirkpatrick, Umesh D Parashar, Mark S Riddle, Judd L Walson, JAMA

Press Mentions

Doctor: Growing Evidence COVID Vaccines Reduce Transmission, InfectionsApril 12th, 2021
UNR School of Medicine Doctor Breaks down How COVID-19 Vaccines WorkApril 9th, 2021
Experts: Avoid Brand “Shopping” for COVID-19 VaccineMarch 13th, 2021
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