Migration continues to be an essential ingredient of socioeconomic development everywhere. Whether it is a case of people moving from the countryside to cities to find work, or people crossing seas and borders to meet host country demands for new labour, migrants are an integral part of the modern world. They bring with them new skills and talents, and a willingness to take on jobs that host societies have difficulty filling. Despite this, migrants tend to be overlooked by many health and social service systems. They are also vulnerable to exclusion, stigma and discrimination, particularly if “undocumented” or irregular. Today, in the context of COVID-19, a neglect of migrants will make it impossible to stem the pandemic. These Notes are designed to remind national and local authorities that the war against COVID-19 cannot be won if migrants are forgotten; unus pro omnibus, omnes pro uno”, or one for all, and all for one, must guide the fight against COVID-19.