By CBSBoston.com Staff

BOSTON (CBS) –  After Massachusetts residents 75 and older experienced issues and long delays on the first day they were eligible to sign up for appointments to receive their COVID-19 vaccine, the state laid out more details Thursday about the appointment rollout.

The state’s COVID-19 Command Center said it will be posting large batches of available appointments every Thursday at the state’s current mass vaccination sites – Gillette Stadium, Fenway Park, Eastfield Mall in Springfield and the DoubleTree Hotel In Danvers.

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Smaller sites like CVS Health will post new appointments daily, totaling about 8,000 a week across eight sites.

Signups began Wednesday for residents 75 and older, in advance of Phase 2 of the state’s COVID vaccine plan. Those residents are eligible for shots starting Monday, February 1. At mass vaccination states in Springfield and Danvers, 10,000 appointments were made available on Wednesday, and they were booked within hours.

On Thursday, Springfield and Danvers opened another 15,000 appointments. Gillette Stadium and Fenway Park posted a total of 20,000 appointments Thursday.

Read: When Can I Get My COVID Vaccine?

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“The high volume of people working to secure appointments all at once, it was a very frustrating day – we know that – for everybody, especially for those who are looking to book an appointment and couldn’t find one,” said Gov. Charlie Baker. “Right now, there’s obviously a high demand for a limited number of appointments.”

Find: Massachusetts Vaccination Sites

The state says the number of appointments is based on the available number of doses given to them by federal government, which is expected to increase in upcoming weeks.

According to Baker, Massachusetts will also launch a telephone call center for residents who are unable to sign up for their COVID vaccine using the state’s website.

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Visit Mass.Gov/CovidVaccine to find out when you’re eligible and to book an appointment.

CBSBoston.com Staff