FOR OBVIOUS reasons, 2020 will not go down as a good year. At the same time, it has brought more scientific progress than any year in recent memoryâand these advances will last long after COVID-19 as a major threat is gone. Two of the most obvious and tangible signs of progress are the mRNA vaccines now being distributed across America and around the world. These vaccines appear to have very high levels of efficacy and safety, and they can be produced more quickly than more conventional vaccines. They are the main reason to have a relatively optimistic outlook for 2021. The mRNA technology also may have broader potential, for instance by helping to mend damaged hearts.