The rapid development of COVID-19 vaccines is one of medicine’s greatest achievements, but distribution hasn’t been easy. Vials full of doses often must be kept in extreme cold, and once opened have to be used quickly, sometimes prompting health workers to run out into the street looking for someone to take the leftovers.
Now vaccination campaigns in the United States and some other countries are moving from mass demand to more targeted efforts to reach the hesitant — and doctors want easier ways to deliver shots.
The ideal in many instances would be a pre-filled syringe, simple to store with no excess to worry about. But drugmakers haven’t made that a priority yet, and other measures to deliver vaccines to smaller, farther-flung populations are coming along slowly, presenting a challenge in the next phase of the immunization effort.