He holds a PhD in Biostatistics from Christian Medical College Vellore. His experience includes a decade of work at the Wellcome Trust Research Lab, CMC, Vellore, where he actively participated in various observational cohort studies, multicentre studies, and clinical trials. Notably, he contributed to the MAL-ED study, a birth cohort initiative spanning 8 countries and encompassing a 5-year follow-up period. Furthermore, he played a significant role in the Surveillance of Enteric Fever in India study, generously funded by the BMGF, which was conducted across 18 sites spanning three distinct tiers throughout India.
Following the completion of his PhD, he served as the Lead Biostatistician at PAREXEL International Ltd for a span of three years. In this capacity, he was extensively involved in Early Phase clinical trials, including studies involving Bioavailability (BA), Bioequivalence (BE), and Drug-Drug interaction (DDI). Throughout this tenure, he oversaw the comprehensive lifecycle of each study, encompassing critical aspects such as CRF development, Statistical Analysis Plan (SAP) formulation, Protocol creation, final analysis execution, the generation of TLFs, and the compilation of the Clinical Study Report (CSR).
His research focus centres on a diverse array of areas within biostatistics. These encompass the realms of longitudinal data analysis, Generalized Linear Models (GLMs), multi-level models, count regression models, survival analysis, machine learning, and spatial analysis.

1. John J, Bavdekar A, Rongsen-Chandola T, Dutta S, Gupta M, Kanungo S, Ramanujam K, et al. Burden of typhoid and paratyphoid fever in India. N Engl J Med. 2023;388(16):1491–500.
2. Platts-Mills JA, Liu J, Rogawski ET, Kabir F, Lertsethtakarn P, Siguas M, Ramanujam K, et al. Use of quantitative molecular diagnostic methods to assess the aetiology, burden, and clinical characteristics of diarrhoea in children in low-resource settings: a reanalysis of the MAL-ED cohort study. Lancet Glob Health. 2018;6(12):e1309–18.
3. Karthikeyan AS, Srinivasan M, Kanungo S, Sinha B, Shrivastava A, Ramanujam K, et al. Antibiotics for fever among children: findings from the surveillance for enteric fever in India cohorts. J Infect Dis. 2021;224(Supplement_5):S494–501.
4. Thomas S, Raju R, Ramanujam K, Ks A, John J, Kang G. Antimicrobial use in two-week recall of febrile illness: A descriptive study based on Healthcare Utilization Survey in India. Int J Infect Dis. 2020 Dec 1;101:94–5.
5. Koshy B, Srinivasan M, Zachariah SM, Karthikeyan AS, Roshan R, Bose A, Ramanujam K, et al. Body iron and lead status in early childhood and its effects on development and cognition: a longitudinal study from urban Vellore. Public Health Nutr. 2020;23(11):1896–906.
6. Kosek MN, Ahmed T, Bhutta Z, Caulfield L, Guerrant R, Houpt E, Ramaujam K, et al. Causal pathways from enteropathogens to environmental enteropathy: findings from the MAL-ED birth cohort study. EBioMedicine. 2017;18:109–17.
7. Thomas RJ, Ramanujam K, Velusamy V, Puthupalayam Kaliappan S, Kattula D, Muliyil J, et al. Comparison of fieldworker interview and a pictorial diary method for recording morbidity of infants in semi-urban slums. BMC Public Health. 2015;15(1):1–6.
8. Kumar D, Sharma A, Rana SK, Prinja S, Ramanujam K, Karthikeyan AS, et al. Cost of illness due to severe enteric fever in India. J Infect Dis. 2021;224(Supplement_5):S540–7.
9. Koshy B, Srinivasan M, Bose A, John S, Mohan VR, Roshan R, Ramanujam K, et al. Developmental trends in early childhood and their predictors from an Indian birth cohort. BMC Public Health. 2021;21:1–8.
10. McCormick BJ, Richard SA, Caulfield LE, Pendergast LL, Seidman JC, Koshy B, Ramanujam K et al. Early life child micronutrient status, maternal reasoning, and a nurturing household environment have persistent influences on child cognitive development at age 5 years: results from MAL-ED. J Nutr. 2019;149(8):1460–9.
11. Mohan VR, Sharma S, Ramanujam K, Babji S, Koshy B, Bondu JD, et al. Effects of elevated blood lead levels in preschool children in urban Vellore. Indian Pediatr. 2014;51:621–5.
12. Amour C, Gratz J, Mduma E, Svensen E, Rogawski ET, McGrath M, et al. Epidemiology and impact of Campylobacter infection in children in 8 low-resource settings: results from the MAL-ED study. Clin Infect Dis. 2016;63(9):1171–9.
13. John SM, Thomas RJ, Kaki S, Sharma SL, Ramanujam K, Raghava MV, et al. Establishment of the MAL-ED birth cohort study site in Vellore, southern India. Clin Infect Dis. 2014;59(suppl_4):S295–9.
14. Reddy N S, Sindhu KN, Ramanujam K, Bose A, Kang G, Mohan VR. Exclusive breastfeeding practices in an urban settlement of Vellore, southern India: findings from the MAL-ED birth cohort. Int Breastfeed J. 2019;14(1):1–6.
15. Srinivasan M, Sindhu KN, Ramanujam K, Ramasamy RK, Subramaniam S, Ganesan SK, et al. Factors predicting blood culture positivity in children with enteric fever. J Infect Dis. 2021;224(Supplement_5):S484–93.
16. Cao Y, Karthikeyan AS, Ramanujam K, Raju R, Krishna S, Kumar D, et al. Geographic pattern of typhoid fever in India: a model-based estimate of cohort and surveillance data. J Infect Dis. 2021;224(Supplement_5):S475–83.
17. Mohan VR, Srinivasan M, Sinha B, Shrivastava A, Kanungo S, Natarajan Sindhu K, Ramanujam K, et al. Geographically weighted regression modeling of spatial clustering and determinants of focal typhoid fever incidence. J Infect Dis. 2021;224(Supplement_5):S601–11.
18. Raju R, Kezia Angelin J, Karthikeyan AS, Kumar D, Kumar R R, Sahai N, Ramanujam K et al. Healthcare utilization survey in the hybrid model of the Surveillance for Enteric Fever in India (SEFI) study: processes, monitoring, results, and challenges. J Infect Dis. 2021;224(Supplement_5):S529–39.
19. Koshy B, Karthikeyan A, Bose A, Roshan R, Ramanujam K, Mohan VR, et al. Home environment: Short-term trends and predictors in early childhood from an Indian community birth cohort. Child Care Health Dev. 2021;47(3):336–48.
20. Sindhu KN, Ramamurthy P, Ramanujam K, Henry A, Bondu JD, John SM, et al. Low head circumference during early childhood and its predictors in a semi-urban settlement of Vellore, Southern India. BMC Pediatr. 2019;19:1–11.
21. Manuel M, Ramanujam K, Ajjampur SS. Molecular tools for diagnosis and surveillance of soil-transmitted helminths in endemic areas. Parasitologia. 2021;1(3):105–18.
22. Mohan VR, Karthikeyan R, Babji S, McGrath M, Shrestha S, Shrestha J, et al. Rotavirus infection and disease in a multisite birth cohort: results from the MAL-ED study. J Infect Dis. 2017;216(3):305–16.
23. Kaliappan S, Ramanujam K, Manuel M, Farzana J, Janagaraj V, Laxmanan S, et al. Soil-transmitted helminth infections after mass drug administration for lymphatic filariasis in rural southern India. Trop Med Int Health. 2022;27(1):81–91.
24. Sharma SL, Reddy N S, Ramanujam K, Jennifer MS, Gunasekaran A, Rose A, et al. Unintentional injuries among children aged 1–5 years: understanding the burden, risk factors and severity in urban slums of southern India. Inj Epidemiol. 2018;5(1):1–10.