My own research interests include statistical modelling and analysis of infectious disease data, estimation of vaccine efficacy from trial and field data, dynamics of pneumococcal carriage and its relation to disease, and the effects of vaccination on the epidemiology of the pneumococcus. I have a special interest in Bayesian analysis of incompletely observed infectious disease data and Markov chain Monte Carlo methods applied to deal with the problem. My recent publications in the field of infectious disease data include a survey study of the intensity of social contacts and an analysis of the effectiveness of case isolation and quarantine during the early phase of the SARS-CoV-2 pandemic in Finland. Through my students, I have recently become involved in the analysis of causal mediation in cohort and microbiome studies.