MA has about 30% of people fully vaccinated. In Israel, the rate of new cases cratered once that number hit close to 50% and has stayed extremely low ever since (despite reopenings and the rate of new vaccinations there slowing to a crawl).
Vaccines were distributed based on population, not demand. We can't vaccinate people fast enough because we didn't get enough doses (see my other post in this thread). Now that other states have a stockpile sitting around, MA might get more doses and with general availability this week, our numbers should improve.
Sewerage isn’t particularly accurate. Australian cities have been Covid free for the last 6 months yet there are continual reports of virus in the sewerage. It seems some recovered cases shed the virus for months after the infectious period.