Elementary school campuses in Los Angeles County could be eligible to reopen in two to three weeks if countywide coronavirus infection rates continue to drop, county Public Health Department Director Barbara Ferrer said Wednesday.

While the possibility of a quick return is sure tothrill some parents and students, school officials and some local advocacy groups expressed caution. And Ferrer warned that the current positive trend could easily reverse.

With Gov. Gavin Newsom’s lifting this week of a state stay-at-home directive, more businesses are reopening or expanding their services, and the rules on social gatherings have been slightly eased.

For schools to be able to open “assumes that everybody continues to do their very best — play by the rules to keep making sure that transmission goes down and not back up,” Ferrer said.

Even if rates continue to decline, formidable hurdles still could delay reopening, including the readiness of campus safety measures, union negotiations and the availability of vaccines for teachers and other school staff.

“It’s concerning to hear this kind of public pronouncement after weeks of alarmingly high case rates, hospitalizations, and deaths, particularly for low-income communities and communities of color,” said Los Angeles school board President Kelly Gonez. “I would like to continue to see a trend of significant decline in COVID-19 spread to avoid setting up in-person supports only to have to close them down again as we did in December.

“Once the conditions are truly safe,” she added. “I want to make sure L.A. Unified builds on last semester’s supports, like expanding childcare, tutoring, and special education services so we can reach more students and meet the holistic needs of our students.”

The in-person supports had reached fewer than 1% of district students when they were put on hold last month amidthe coronavirus surge.

The L.A.Unified School District and the teachers union continue to negotiate over what a return to campus would look like. The improving health trends could bring new urgency to these talks. Neither L.A. schools Supt. Austin Beutner nor the union has committed to a timetable for resuming in-person services.

Ferrer’s projection was based both on modeling from experts working with the county and on how quickly infection rates are falling.

For transitional kindergarten through sixth grade to be eligible for reopening in-person instruction, the seven-day average of daily cases would have to be 25 or fewer per 100,000 residents. The bar for middle and high school students is higher: seven cases or fewer per 100,000.

Last week, the county’s adjusted case rate was about three times the reopening standard. This week, the rate was less than twice as high, or about 48 cases per 100,000.

Ferrer offered her analysis in comments to the L.A. City Council and in a later media briefing.

“I think if we continue to decrease, you might hit that number in like two to three weeks,” Ferrer told the council.

“We dropped pretty significantly just in one week.”

The vast majority of county students have been learning from home since March; many have struggled with inadequate internet access and difficult learning environments.

Pandemic learning disparities have especially affected students from low-income families, those learning English and students with disabilities.

There also are ongoing safety concerns — the students suffering most academically live in the communities most ravaged by COVID-19.

Some advocacy groups expressed concerns about reopening.

“It would be insane for L.A. to launch into reopenings this soon after the winter surge and not expect yet another surge in a month or so,” said John Kim, executive director of the California Office of Advancement Project.

The advocacy group Speak Up said in-person services should be provided to students, prioritizing those with high needs, as soon as county health officials determined it was safe to do so.

Sarah Reimers, a parent at Walgrove Elementary in Mar Vista, said she is “more than ready” for her fourth-grade son to return. Based on what she’s read, Reimers said, “we are convinced that the harm keeping kids out of school is greater than the risks of sending them to school.”

Some parents are organizing statewide to make the case that campuses should reopen without unnecessary delay.

“We are encouraged to see L.A. County’s numbers going down, as safely reopening schools should be the top priority,” said Ross Novie, a local parent organizer for Open Schools California.

“This underscores why school districts need to be ready with their reopening plans, so they can finally, after 320 days, safely return to the classroom.”

In recent days, attention has been focused on efforts to get teachers vaccinated against COVID-19 as a critical step toward resuming in-person instruction.

Both Beutner and the leaders of the teachers union have called for immunizations, while also noting that low infection rates and other metrics are part of the picture as well.

Beutner has said repeatedly — including on Wednesday — that campuses are structurally ready to go and that they’ll be operated safely when the time comes.

Times staff writer Jaclyn Cosgrove contributed to this report.