Child care workers contracted with the city for programs such as pre-K, 3-K and after-school education will be required to receive at least one vaccine dose before Sept. 27, Mayor Bill de Blasio announced at a Thursday news conference. 

The mandate expands an existing vaccination requirement for all city education department staff, which also goes into effect Sept. 27. 

Staff for EarlyLearn, Homebase, Cornerstone and other city education programs are included in the mandate. 

"All of these are so important to supporting our young people, and we want them to be safe for our young people," de Blasio said of the programs. 

The mandate comes days before a vaccinate-or-test requirement for all municipal employees goes into effect Monday. Workers who do not get vaccinated will be required to test for the coronavirus weekly. Some agencies, like the NYPD, have told employees they must test on their own time.