Three teachers in Florida’s second-largest school district have died from Covid-19 within two days of each other, union officials report.

The deaths come just days before Broward County schools reopen on Aug. 18.

Florida’s Republican governor has threatened to withhold pay from school officials who require masks for students.

The virus protocols in schools have become the subject of intense debate as the Delta variant spreads in the United States.

Broward teachers union president Anna Fusco initially said four teachers had died, but the union clarified later Friday that only two were teachers, a third was a teaching assistant and a fourth was a graduate. The union said they had died from complications related to Covid-19.

They also said three of them were unvaccinated. None had been inside a school building recently.

The four were said to have died between Tuesday and Wednesday in Broward County, which is north of the Miami-Dade area. Their names were not released.

The news comes as students in Broward County prepare to return to the classroom next week. The district is the sixth-largest in the country, with more than 272,000 students.

The Broward school board voted this week to require students to mask in schools, defying Gov. Ron DeSantis’ order and his threat to withhold salaries from leaders who do so.

The county leads the nation in new hospital admissions for Covid during the Aug. 3-9 period, according to data from the U.S. Department of Health and Human Services. Neighboring Miami-Dade County is third in the rankings.

Florida and Texas account for about 40% of all new hospital admissions nationwide, with increasing numbers of young people needing hospital care because of the virus.

However, Florida has only the 26th highest Covid-19 death rate in the United States, with 185 deaths per 100,000 population, according to Statista. This is despite the fact that the Sunshine State has one of the most aging populations in the United States.

The highest death rate is in New Jersey, with 300 deaths per 100,000 people, followed by New York and Massachusetts.

But Broward County Mayor Steve Geller said Thursday, “Our numbers are horrible. The number of children’s causes is horrible, and it’s also rising rapidly.”

Clashes between governors and local school districts over Covid’s rules have occurred across the United States ahead of the new academic year.

Another Florida superintendent warned earlier this week that two employees have died from the virus in the past two weeks, “and classes haven’t even started.”

Federal health officials warned Thursday that 90% of U.S. counties had the high transmission of the Delta variant.

The director of the Centers for Disease Control, Rochelle Walensky, reported that in the U.S. there were about 113,000 new cases per day in the last week.