The greatest advances in science are often made by teams that span countries and cultures. Yet visa delays, travel restrictions and security concerns are making international collaboration harder.
There are legitimate reasons to protect sensitive research. But blanket restrictions are blunt instruments that deter talented people, slow progress on shared challenges such as climate change and pandemics, and ultimately weaken the countries that impose them.
We urge policymakers to adopt targeted, transparent measures and to keep the doors of science open.
