Dr Siddhartha Datta is a medical professional with a public health background, currently serving as the Regional Advisor of the Vaccine-preventable diseases and immunization programme at the WHO Regional Office for Europe. He is committed to strategizing public health policies with a pragmatic and operational outlook to drive real change in the lives of those who need it most. Leading a large team at the WHO Regional Office, in the past year he has supported countries throughout the European Region in the unprecedented task of preparing for and rolling out new life-saving vaccines to help stop the COVID-19 pandemic.