His research work has significantly contributed to the introduction of rotavirus vaccine into childhood vaccination programs worldwide. Timo Vesikari has worked with World Health Organization in 1988–1990 and been a member of many WHO committees over the years. He has published over 350 peer reviewed articles and co-edited a textbook on Pediatric Vaccines and Vaccinations (published 2017).

VRC under the leadership of Professor Vesikari has conducted many pivotal vaccine trials leading to the licensure and implementation of several vaccines in addition to rotavirus vaccines. These include single and combined varicella vaccines, herpes zoster vaccines, live attenuated influenza vaccine, adjuvanted non-live influenza vaccine, pneumococcal conjugate vaccines, new hexavalent infant vaccines and meningococcal vaccines. NRN in association with the University of Tampere has conducted three major clinical trials from 2007 to present. These studies have been on avian influenza vaccine, live herpes zoster vaccine and, lastly, a new hepatitis B vaccine. All studies conducted by NRN have been in healthy adult volunteers ≥ 18 years of age. Professor Vesikari’s current research interest is development of norovirus vaccines. He is a co-owner of a patent on a combined rotavirus VP6 and norovirus VLP vaccine.