A year after first COVID-19 vaccine, here's what's next for researchers – and what worries them

A year ago today the firstCOVID-19 vaccines were given out, and more than 450 million shots have been administered across America since. The rapid development and manufacturing has been described as one of the greatest scientific achievements of our time.

With all that progress – not to mention billions of dollars spent on vaccine development – what's next for vaccines? 

Researchers are racing to create variant-specific boosters, the first of which could be available as soon as March. Scientists are also working on vaccines that will act against a broader range of variants and viruses, as well as ways to preserve doses so they will be...