Imperial College London


Faculty of MedicineSchool of Public Health

Prof of Infectious Disease & Vaccine Epidemiology



+44 (0)20 7594 3264n.grassly Website




G36Medical SchoolSt Mary's Campus






I am interested in infectious diseases, particularly intestinal infections, and the role of vaccines in their prevention. I have a background in biology and mathematics, and head the Vaccine Epidemiology research group within the Department of Infectious Disease Epidemiology at Imperial College London.

Over the last decade I have worked extensively on poliovirus, identifying failure of the oral vaccine in India as a major challenge to global eradication. This work has led to clinical trials that aim to improve mucosal immunity and limit vaccine failure, which I am currently pursuing in collaboration with colleagues at the Christian Medical College in Vellore (where I am an adjunct faculty member). 

A major focus of our current research is to understand and improve the response to live oral vaccines, which are poorly immunogenic when given to children in low-income countries. Through clinical trials and new technologies including immunophenotyping arrays and next generation sequencing we are uncovering the relationship between the intestinal microbiota, immune function and response to vaccination.

We also work closely with the Global Polio Eradication Initiative as a collaborating institute on data analysis and modelling. We provide evidence from epidemiological studies, clinical trials and analysis of surveillance data to support decision making by the Initiative. We have estimated the effectiveness of new monovalent and bivalent vaccines, the impact of novel strategies for vaccine delivery and role of different populations and age-groups in poliovirus transmission. 

For more details of the current research interests of my group, please click on the link above.

I supervise a number of PhD students working on infectious diseases and vaccine epidemiology. If you are interested in joining our group please email me.

You can also follow us on Twitter @VaccineEpi.

Selected recent publications

Jafari H, Deshpande JM, Sutter RW, Bahl S, Verma H, Ahmad M, Kunwar A, Vishwakarma R, Agarwal A, Jain S, Estivariz C,Sethi R, Molodecky NA, Grassly NC, Pallansch MA, Chatterjee A, Aylward RB (2014) Efficacy of inactivated poliovirus vaccine in India. Science 345:922-925 [abstract]

John J, Giri S, Karthikeyan AS, Iturriza-Gomara M, Muliyil JP, Abraham A, Grassly NC* and Kang G* (2014) Effect of a single inactivated poliovirus vaccine dose on intestinal immunity against poliovirus in children previously given oral vaccine: an open-label, randomised controlled trial. Lancet early 384:1505-1512 [abstract]. ,*joint first,senior authors

Blake IM, Martin R, Goel A, Khetsuriani N, Everts J, Wolff C, Wassilak S, Aylward RB and Grassly NC (2014) The role of older children and adults in wild poliovirus transmission Proc Natl Acad Sci USA Vol:111:10604-10609 [full text]

Mangal TD, Aylward RB, Mwanza M, Gasasira A, Abanida E, Pate MA and Grassly NC (2014) Key issues in the persistence of poliomyelitis in Nigeria: a case-control study Lancet Global Health 2:e90-e97. [full text]

O'Reilly KM, Durry E, ul Islam O, Quddus A, Abid N, Mir TP, Tangermann RH, Aylward RB and  Grassly NC (2012). The effect of mass immunisation campaigns and new oral poliovirus vaccines on the incidence of poliomyelitis in Pakistan and Afghanistan, 2001-11: a retrospective analysis. Lancet. 380:491-8. [full text]

Grassly NC, Jafari H, Bahl S, Sethi R, Deshpande JM, Wolff C, Sutter RW and Aylward RB (2012). Waning intestinal immunity following vaccination with oral poliovirus vaccines in India. J Infect Dis 205: 1554-1561. [abstract]

Hird TR and Grassly NC (2012). Systematic review of mucosal immunity induced by oral and inactivated poliovirus vaccines against virus shedding following oral poliovirus challenge. PLoS Pathog  8(4): e1002599. [fulltext]

O'Reilly, K. M., C. Chauvin, R. B. Aylward, C. Maher, S. Okiror, C. Wolff, D. Nshmirimana, C. A. Donnelly and N. C. Grassly (2011). A statistical model of the international spread of wild poliovirus in Africa used to predict and prevent outbreaks." PLoS Med 8(10): e1001109. [full text]

Jenkins HE, Aylward RB, Gasasira A, Donnelly CA, Mwanza M, Corander J, Garnier S, Chauvin C,Abanida EA, Pate MA, Adu F, Baba M & Grassly NC Implications of a circulating vaccine-derived poliovirus in Nigeria. New Engl J Med 2010. 362: 2360-9. [full text]


Blake IM, Chenoweth P, Okayasu H, et al., 2016, Faster Detection of Poliomyelitis Outbreaks to Support Polio Eradication, Emerging Infectious Diseases, Vol:22, ISSN:1080-6040, Pages:449-456

John J, van Aart CJC, Grassly NC, 2016, The Burden of Typhoid and Paratyphoid in India: Systematic Review and Meta-analysis, Plos Neglected Tropical Diseases, Vol:10, ISSN:1935-2735

Grassly NC, Praharaj I, Babji S, et al., 2016, The effect of azithromycin on the immunogenicity of oral poliovirus vaccine: a double-blind randomised placebo-controlled trial in seronegative Indian infants., Lancet Infect Dis

Lopman BA, Grassly NC, 2016, Editorial Commentary: Pediatric Norovirus in Developing Countries: A Picture Slowly Comes Into Focus., Clin Infect Dis, Vol:62, Pages:1218-1220

Grassly NC, 2015, New vaccine strategies to finish polio eradication, Lancet Infectious Diseases, Vol:15, ISSN:1473-3099, Pages:864-865

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