Massachusetts will launch a program next week to bring vaccines directly to its roughly 25,000 homebound residents, offering doses either through local boards of health or a statewide service. The program will start on Monday, March 29, allowing those who are unable to travel to a vaccine location without significant difficulty or assistance to receive shots in their own homes, Gov. Charlie Baker and Health and Human Services Secretary Marylou Sudders announced Thursday. In 170 cities and towns, local boards of health will administer vaccines to their residents. A statewide service operated by the Commonwealth Care Alliance will assist residents in the other 181 municipalities. Home bound residents or their relatives can call 1-844-771-1628 to begin the process of scheduling an in-home vaccine appointment. The line will be open Monday through Friday from 9 a.m. to 5 p.m., available in English and Spanish and with translators available for other languages