As organizers of an open letter (see to the US government, signed by more than 1,000 scientists, we are calling for an urgent update to the COVID-19 travel restrictions affecting international researchers holding US visas. These scientists cannot re-enter the United States from any of more than 30 countries, including most of Europe (see

Since July, many areas affected by the US travel ban have had higher vaccination rates and lower infection rates than the United States. By contrast, some high-risk countries, such as Mexico, Russia and Turkey, are on the US government’s approved list. And despite the ban, the Delta SARS‑CoV-2 variant now comprises 92% of new US COVID-19 cases.

The restrictions are discriminatory: re-entry is unconditional for US citizens and for most with student visas. US government policies have prevented most international scholars from visiting their home country for almost 18 months. Their mental health and careers, as well as the output of US research institutions, have been adversely affected.

As US-based researchers, we firmly believe that the inconsistencies behind these policies undermine the scientific community and efforts to protect public health. In our view, policies should instead be based on individual travel-risk assessments.