“I think everyone who covered me really did their best,” she said. But “the art teacher is not going to teach fourth grade math the same as me.”

Substitute teachers are “a short-term plaster that hurts students,” said Kim Anderson, executive director of the National Education Association, which represents millions of education workers across the country.

The problem begins with the need for more full-time teachers in many school districts. In Arizona, nearly 1,400 teachers left the profession in the first few months of the school year, according to a study. In Florida, the school year began with nearly 5,000 teaching positions, from a video published by Florida Education Association President Andrew Spar.

Low wages, high stress and difficult working conditions have plagued the profession for years. But fear of contracting the coronavirus has created “the perfect storm,” Ms. Anderson said, and teachers are now leaving or retiring earlier.

“School districts are really relying on substitutes because there are lots and lots of teachers who have left the field,” said Anderson.

Oregon once had 8,290 certified substitute teachers, but by September 18 that number had been cut in half. To create a larger swimming pool, the State, in an October 1 emergency order, created a new license. These substitutes no longer need to take several tests or have a baccalaureate. They simply need to be at least 18 years of age, sponsored by a participating district or charter school, and of “good moral character” with the “necessary mental and physical health” to teach.

In the two weeks after the measure was passed by Oregon, more than 180 people applied to work as a substitute in public schools in Portland, the state’s largest district, according to Sharon Reese, director of schools. district human resources.