VANCOUVER -- British Columbia's COVID-19 immunization program will mark another milestone this weekend when the province begins inviting all eligible adults to book their appointment.

Starting at 7 p.m. Sunday, invitations will start getting sent out to anyone 18 and older who has registered through B.C.'s Get Vaccinated website, health officials announced Thursday.

Currently, anyone age 30 and up can book their shot, and the system will expand to include anyone 25 and up on Friday evening. People 20 and up will have their chance on Saturday evening.

Provincial health officer Dr. Bonnie Henry shared new data on the impacts of B.C.'s immunization program on Thursday, revealing that groups and areas that have had widespread access to vaccine protection have seen COVID-19 cases plummet.

That includes health-care workers employed in long-term care homes and assisted-living facilities, who experienced a "dramatic drop-off" in infections that continued even through the province's record-breaking third wave of the pandemic, Henry said.

She also pointed to Prince Rupert, the northern community that was targeted for early immunization back in March amid an explosion in cases. The data shows infections fell quickly and then stayed low even as surrounding areas saw an uptick in cases.

"This is something that helps us understand what may happen as an entire province once we get to those levels of immunization," Henry said.

Earlier this week, B.C. celebrated another milestone after vaccinating half of all eligible adults.

The province has now administered a total of 2,335,513 doses of the Pfizer-BioNTech, Moderna and AstraZeneca vaccines, including 119,691 second doses.