The New York Times reports that the public schools of New York City have been conducting random drug tests, and the results reveal a surprisingly small number of COVID-19 infections. The city might be a “national model.”

For months, as New York City struggled to start part-time, in-person classes, fear grew that its 1,800 public schools would become vectors of coronavirus infection, a citywide archipelago of super-spreader sites.

But nearly three weeks into the in-person school year, early data from the city’s first effort at targeted testing has shown the opposite: a surprisingly small number of positive cases.

Out of 15,111 staff members and students tested randomly by the school system in the first week of its testing regimen, the city has gotten back results for 10,676. There were only 18 positives: 13 staff members and five students.

And when officials put mobile testing units at schools near Brooklyn and Queens neighborhoods that have had new outbreaks, only four positive cases turned up — out of more than 3,300 tests conducted since the last week of September.

New York City is facing fears of a second wave of the virus brought on by localized spikes in Brooklyn and Queens, which have required new shutdown restrictions that included the closure of more than 120 public schools as a precaution, even though few people in them have tested positive.

But for now, at least, the sprawling system of public schools, the nation’s largest, is an unexpected bright spot as the city tries to recover from a pandemic that has killed more than 20,000 people and severely weakened its economy.

If students can continue to return to class, and parents have more confidence that they can go back to work, that could provide a boost to New York City’s halting recovery.

The absence of early outbreaks, if it holds, suggests that the city’s efforts for its 1.1 million public school students could serve as an influential model for school districts across the nation.

In September, New York became the first big urban district to reopen schools for in-person learning.

Roughly half of the city’s students have opted for hybrid learning, where they are in the building some days, but not others. The approach has enabled the city to keep class sizes small and create more space between desks.

Since then, large school districts across Florida have opened for in-person learning, too. Some wealthier districts in the New York suburbs declined to take this step, worried that it was too risky and logistically challenging.

The city’s success so far could put much more pressure on other districts that have opted for only remote instruction to start considering plans to bring their children back as well.

“That data is encouraging,” said Paula White, executive director of Educators for Excellence, a teachers group. “It reinforces what we have heard about schools not being super spreaders.”

So far, it is also good news for Mayor Bill de Blasio, who has staked much of his second-term legacy on reopening schools for in-person learning during the pandemic.

While public health experts said the data was encouraging, they also cautioned that it was still early.

In general, maintaining low levels of infection at schools would depend on how well New York City does in holding off a broader spread in the population.

Also, some experts have called for much more frequent random testing in all schools — something that city officials are considering — in order to increase the odds of discovering an outbreak early.

So far, most coronavirus testing for school workers has taken place at city-run sites outside the purview of the education department.

Out of 37,000 tests of staff members at city sites, 180 were positive, a city official said.

According to separate data reported to the state by local school districts, 198 public school students in New York City have tested positive since Sept. 8. (Gov. Andrew M. Cuomo in early September ordered those conducting coronavirus tests to collect school information on children, but so far compliance has been spotty, state officials said.)

The city’s new schools testing regimen, which began Oct. 9, calls for 10 to 20 percent of the school population to be tested once a month, depending on the size of the school. The city is applying this testing to its 1,600 traditional public schools; the city’s 260 charter schools are not included.

Some researchers have questioned the efficacy of that approach, saying it could miss a large outbreak.

“It’s great that New York City is doing some level of random testing,” said Dr. Ashish Jha, dean of the Brown University School of Public Health. “It’s not at the level that would be ideal.”

One study recommended testing half the students twice a month.

Michael Mulgrew, president of the teachers union, said the city is looking to increase testing to as much as three times a month citywide. Such frequency, he said, would be “much more valuable” in terms of keeping the virus in check…

A positive test of a student or teacher causes the city to spring into action. Under the rules, one case can cause the closure of a classroom. Two or more cases in separate parts of the same school can prompt a temporary schoolwide closure. At least 25 schools have temporarily closed since classes began. But only three were closed as of Friday…

A positive test of a student or teacher causes the city to spring into action. Under the rules, one case can cause the closure of a classroom. Two or more cases in separate parts of the same school can prompt a temporary schoolwide closure. At least 25 schools have temporarily closed since classes began. But only three were closed as of Friday.