CHICAGO (CBS) — The Chicago Department of Public Health says the United Center mass vaccination site will only be open another three weeks.

The first week, workers will only offer the Johnson & Johnson single-dose vaccine. Then, the next two weeks the United Center will give out second doses of the Pfizer vaccine to people who already got their first shot.

READ MORE: Two Chicago Police Officers Wounded By Accidental Friendly Fire While Confronting Suspect In Lyons, Police Say

In just eight weeks since it opened, the United Center clinic has given out more than 250,000 shots.

READ MORE: Boy, 16, Charged In West Humboldt Park Carjacking

Meantime, Chicago Public Schools leaders are working on plans to give students the COVID vaccine by the end of this school year.

Outgoing CPS Chief Executive Officer Janice Jackson said the district is on track to help with vaccine distribution before classes let out for the summer, but those vaccination efforts would continue when school is out.

MORE NEWS: Woman Had Her Medicare Card Stolen And Her Name Used To Order Medical Tests, And She's Not Alone

Right now, the Pfizer vaccine is the only COVID-19 vaccine approved for those age 16 and 17, and the FDA could soon approve its use for those as young as 12.

CBS 2 Chicago Staff