(AP) — The Los Angeles board of education is expected to vote Thursday on whether to require all students 12 and older to be fully vaccinated against the coronavirus to participate in on-campus instruction in the nation’s second-largest school district.

The proposal, scheduled for discussion at a special afternoon meeting, would be one of the most aggressive measures taken by a major U.S. school district to protect children from infections.

The Los Angeles Times reported that in interviews last week, a majority of board members said they either favored or were leaning toward requiring vaccinations.

The Los Angles Unified School District, which enrolls more than 640,000 students in kindergarten through 12th grade, already tests all students and employees every week, requires masking indoors and outdoors and has ordered employees to be vaccinated.

A significant portion of the district’s students come from low-income families and more than 73% are Latino, a segment of the population that has lagged in getting vaccinated.

The proposal would require students 12 and up who are participating in sports and other activities to receive a first dose of vaccine by Oct. 3 and a second dose by Oct. 31. All other students 12 and up would have to get a first dose by Nov. 21 and the second dose no later than Dec. 19.

Currently, the final day of classes before winter break is Dec. 17. Classes resume Jan. 11.

The vote comes as new COVID-19 cases and hospitalizations in Los Angeles County have been decreasing but the rate of transmission remains high, according to the county Department of Public Health.

“Without a significant increase in the numbers of eligible residents vaccinated, there is a risk of case increases this fall and winter as COVID-19 is easily spread among those unvaccinated,” Public Health Director Barbara Ferrer said in a statement Wednesday.

The health department reported on Sept. 1 that between Aug. 15 and Aug. 21, unvaccinated youth 12 to 17 years old had eight times the risk of infection than those who had been vaccinated.

“The most powerful strategy for keeping schools open is increasing vaccination numbers as fast as possible,” a department statement said at the time.