John Clemens

Professor John Clemens is an infectious disease epidemiologist with over 30 years of experience designing, conducting, and analyzing large, population-based epidemiologic studies and vaccine field trials in low income countries and developing new methodologies for the clinical evaluation of vaccines. A graduate of Stanford (B.S.) and Yale (M.D.) Universities, Dr. Clemens is U.S.-Board Certified in Internal Medicine, and received his post-doctoral research training in clinical epidemiology at Yale. From 1983-88, he served as a research scientist at the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), where he led the first efficacy trial of an oral vaccine against cholera.

After returning to the U.S., he served as Chief of the Epidemiology Section of the Center for Vaccine Development of the University of Maryland, and then as Chief of the Epidemiology Branch of the National Institute of Child Health and Human Development, U.S. National Institutes of Health (NIH). While at NIH he was the Director of the first WHO Collaborating Centre for Vaccine Evaluation in Developing Countries. In 1999 he became the first Director-General of the International Vaccine Institute (IVI) in Korea. While at IVI he led the team that developed a killed oral cholera vaccine (Shanchol) that achieved licensure in India in 2009 and WHO prequalification in 2010 and was the first oral cholera vaccine to be included in the global oral cholera vaccine stockpile funded by Gavi. To date more than 200 million doses of oral cholera vaccine have been released from the stockpile to control cholera in Asia, Africa, and the Caribbean.

In 2011 he moved to UCLA to become Professor of Epidemiology and the Founding Director of a new Center for Global Infectious Diseases, and from 2013-21 Dr Clemens served as the Executive Director of the International Centre for Diarrheal Disease Research, Bangladesh (icddr,b). He has worked as the Senior Scientific Advisor to the Director General of the International Vaccine Institute in Seoul since 2021. Dr. Clemens is the author of over 500 peer-reviewed publications. He was the recipient of the 2010 Sabin Gold Medal and the 2018 Prince Mahidol Award in Public Health for his foundational contributions to the development and introduction of oral cholera vaccines.

Peer Reviewed Publications

Clemens J, Sack DA, Harris J, van Loon F, Chakraborty J, Ahmed F, Rao MR, Khan MR, Yunus M, Huda N, Stanton B, Kay B, Walter S, Eeckels R, Svennerholm A-M, Holmgren J.  Field trial of oral cholera vaccines in Bangladesh: Results from long-term follow-up.  Lancet. 1990; 335: 270-3, 1990.

Clemens J, Brenner R, Rao M, Lowe C. Evaluating new vaccines for developing countries: Efficacy or effectiveness? Journal of the American Medical Association. 1990; 275: 390-7.

Ali M, Emch M, von Seidlein L, Yunus M, Sack D, Rao M, Holmgren J, Clemens J. Herd immunity conferred by killed oral cholera vaccines in Bangladesh. Lancet. 2005; 366:44-49.

Lucas M, Deen JL, von Seidlein L, Wang X-Y, Ampuero J,  Puri M, Ali M, Ansaruzzaman M, Amos J, Cavallier P, Guerin P, McChesney M, Mahoudeau C, Kahozi P, Chaignat C-Barreto A,  Songane F, Clemens JD. The effectiveness of an internationally licensed, two dose oral cholera vaccine when given in a mass vaccination campaign in Beira, Mozambique. New England Journal of Medicine. 2005; 352: 757-67.

Sur D, Lopez A, Kanungo S, Paisley A,  Manna B, Al M,  Niyogi S,  Park JK,  Sarkar B,  Pur M,  Kim D,  Deen J, Holmgren J,  Carbis R,  Rao R, Nguyen TV,  Donner A,  Ganguly NK, Nair GB, Bhattacharya SK,  Clemens JD. Protection and safety of a modified, killed whole cell oral cholera vaccine in India: A cluster-randomized, double-blind, placebo-controlled trial. Lancet. 2009; 374: 1694-702.

Sur D, Ochiai RL, Sujit K, Bhattacharya S, Ganguly N, Ali M, Manna B, Dutta S, Donner A, Kanungo S, Park JK, Puri M, Kim DR, Dutta D, Bhaduri B, Acosta C, Clemens J. A cluster-randomized effectiveness trial of Vi typhoid vaccine in India. New England Journal of Medicine. 2009; 361: 335-44.

Clemens J, Shin S, Ali M. New approaches to the assessment of vaccine herd protection in vaccine trials. Lancet Infectious Diseases. 2011; 11: 482-7.

Qadri F, Ali M, Chowdhury F, Khan A, Saha A, Khan I, Begum Y, Bhuiyan T, Chowdhury M, Uddin M, Khan J, Chowdhury A,  Rahman A, Siddique S, Asaduzzaman M, Akter A, Khan M,You Y, SiddikM,  Saha N, Kabir A, Riaz B, Biswas S, Begum F, Unicomb L, Luby S, Cravioto A, Clemens J. Feasibility and effectiveness of oral cholera vaccine in an urban endemic setting in Bangladesh: A cluster randomised open-label trial. Lancet. 2015; 386: 1362-71.

Qadri F, Wierzba TF, Ali M, Chowdhury F, Khan AI, Saha A,Khan IA, Asaduzzaman M, Akter A, Khan A, Begum YA, Bhuiyan TR, Khanam F, Chowdhury MI, Islam T, Chowdhury AI, Rahman A, Siddique SA, You YA, Kim DR, Siddik AU, Saha NC, Kabir A, Cravioto A, Desai SN, Singh AP, Clemens JD. Efficacy of a single-dose, inactivated oral cholera vaccine in Bangladesh. New England Journal of Medicine. 2016; 374(18):1723 32.

Clemens J, Nair GB, Qadri F, Ahmed T, Holmgren J. Cholera. Lancet. 2017; 390(10101):1539-1549.

Qadri F, Khanam F, Liu X, Theiss-Nyland K, Biswas PK, Bhuiyan AI, Ahmmed F, Colin-Jones R, Smith N, Tonks S, Voysey M, Mujadidi YF, Mazur O, Rajib NH, Hossen MI, Ahmed SU, Khan A, Rahman N, Babu G, Greenland M, Kelly S, Ireen M, Islam K, O'Reilly P, Scherrer KS, Pitzer VE, Neuzil KM, Zaman K, Pollard AJ, Clemens JD. Protection by vaccination of children against typhoid fever with a
Vi-tetanus toxoid conjugate vaccine in urban Bangladesh: a cluster-randomised trial. Lancet. 2012; Aug 9:S0140-6736(21)01124-7. doi:
10.1016/S0140-6736(21)01124-7.

Hoque M, Kim DR, Ahmmed F,l Islam MT, Im J, Tilahun B, Kang S, Khanam F, Chowdhury F,  Ahmed T,  Firoj MG, Aziz A,  Kanungo S, Khan A, Khan MA, Lee J, Pak G, Marks F, Kim J, Azman A, Holmgren  J, Qadri F, Zaman K, Clemens J.    Protection by natural cholera against recurrent cholera over ten years of follow-up in Matlab,Bangladesh: an observational  study. Lancet Microbe.  2025; Jan 4:100981. doi: 10.1016/j.lanmic.2024.100981.