Demand is sure to overwhelm supply at first. Gov. Charlie Baker is urging residents to be patient and expect that it may take a few weeks to lock down an appointment. This past Tuesday, the CDC and FDA recommended a pause on the use of the J&J vaccine while they investigate after reports six women who got the shot suffered blood clots. While that of course will affect the number of appointments available, Baker has said it's not a major disruption here because the state was mostly administering Moderna and Pfizer. The state's online booking system had a few failures early on in the rollout, but Baker has reiterated that the website has been improved, and put under stress tests in preparation for expected spikes in traffic next week.