Employers can soon book appointments at mass vaccination sites — or host pop-up clinics in their offices

Tripadvisor was the first office employer in Massachusetts to transform its headquarters into a vaccination clinic, in February, in partnership with Newton-Wellesley Hospital.David L. Ryan/Globe Staff

The Baker administration on Wednesday said it would launch an employer-based vaccination program beginning on Monday, allowing businesses to snag appointments for their employees.

It’s a sign that Massachusetts has additional capacity and a steady supply of vaccines. In late February, the state suspended a version of an employer-hosted vaccine program before it even started, due to a lack of vaccine supply.

Starting Monday, companies will be able to book a block of appointments at one of seven mass vaccination sites, such as the Hynes Convention Center in Boston and the former Circuit City in Dartmouth. Businesses can use this option through June 30, with first-dose appointments available through June 11, as long as they have at least 10 employees interested in an appointment.

Employers with more than 35 workers who want to be vaccinated can request to host a vaccination clinic at their offices, the state said. These clinics, which can be set up indoors or outdoors on a company’s property, will be available as soon as Monday, and the state added it would prioritize pop-up clinics at businesses in communities with low vaccination rates.

A spokesperson for the Baker administration did not immediately respond to a question about whether family members of employees would be able to use the office-based sites.

At least two large companies in Boston have said they are considering signing. A Fidelity Investments representative said the company is reviewing the employer vaccination program, and a spokesperson for the online retailer Wayfair said it is also exploring the option. In total, the companies employ more than 10,000 workers in Massachusetts.

The start of the program comes less than three months after Marylou Sudders, the state’s health and human services secretary, sent a memo to the business community asking them to “hold off on efforts to set up employer-based vaccination clinics.” (The state had previously solicited their help in the vaccine rollout.) That caught some businesses by surprise, including groups in the life-sciences sector who were already drawing up detailed plans.

So far, the many empty office buildings in Massachusetts have largely been left out of the state’s vaccination efforts, while stadiums, shopping malls, and a vacant retail store have been converted to clinics. Needham-based Tripadvisor was the first local office employer to transform its headquarters into a public clinic, in February, through a partnership with Newton-Wellesley Hospital. After an initial vaccine supply snag, that site is open and administering about 850 doses daily.