Most immediately, halting the use of Johnson & Johnson will slow U.S. vaccination efforts. Not only was Johnson & Johnson one additional tool in the arsenal, but it also requires only one shot, meaning states can vaccinate twice as many people with the same number of appointments. It means that it’s less of a burden on those who are less eager to get vaccinated. And it means that those who receive the shot are fully vaccinated more quickly, because they don’t have to come back for another appointment three to four weeks later. Furthermore, by blowing a very rare potential side effect out of proportion, the news is likely to provide more fodder to anti-vaxxers to spread fears about the vaccine to those still on the fence. The FDA claims the decision was being made out of an “abundance of caution.” After the past year, that’s a phrase I really want to see retired.