Quantifying the effect of delaying the second COVID-19 vaccine dose in England: a mathematical modelling study

The UK was the first country to start national COVID-19 vaccination programmes, initially administering doses 3 weeks apart. However, early evidence of high vaccine effectiveness after the first dose and the emergence of the SARS-CoV-2 alpha variant prompted the UK to extend the interval between doses to 12 weeks. In this study, researchers at the Jameel Institute, Imperial College London, aimed to quantify the effect of delaying the second vaccine dose in England.