“The coronavirus pandemic has not only exposed the differences between who is healthy in this country and who is not — a divide often driven by poverty, racism and a lack of access to health care — but also has dramatized the way in which everyone’s health is connected, said Dr. Sandro Galea, the dean of Boston University’s School of Public Health and co-chairman of Massachusetts’ Emergency Task Force on Coronavirus and Equity. COVID-19 has been such a disaster for the United States because the country underinvested in public health and had no capacity for an organized, centrally coordinated response from federal, state and local governments, said Galea, who has a new book co-written with Dr. Michael Stein called “Pained: Uncomfortable Conversations about the Public’s Health.”