Boston officials urge more residents to get COVID-19 tests. Experts say that message applies to the whole state “The only tool we have besides mask-wearing and social distancing is testing-tracing-isolation-quarantine,” said Samuel Scarpino, a Northeastern University epidemiologist. It is an approach that has worked well for universities in the Boston area, as well as a number of countries around the world that have kept cases from ballooning out of control.