When someone struggles to open a lock with a key that doesn't quite seem to work, sometimes jiggling the key a bit will help. Now, new research from MIT suggests that coronaviruses, including the one that causes COVID-19, may use a similar method to trick cells into letting the viruses inside. The findings could be useful for determining how dangerous different strains or mutations of coronaviruses may be, and might point to a new approach for developing treatments.