Officials in New York City continued to scramble on Wednesday to quell growing clusters of the coronavirus in several neighborhoods in Brooklyn and Queens, as the seven-day average rate of positive test results citywide ticked slightly upward to 1.46 percent.
On Tuesday, Mayor Bill de Blasio reported a significant uptick in the citywide daily positivity rate, driven in part by a rise in nine ZIP codes in Brooklyn and Queens. On Wednesday, the number of ZIP codes where cases were rising at an “alarming rate” grew to 10, health officials said.
The city was also watching seven additional neighborhoods, including parts of Williamsburg, Crown Heights and Bedford-Stuyvesant, where cases were on the rise.
Still, Mr. de Blasio said the daily positivity rate had dropped to .94 percent, after the city had reported on Tuesday a 3.25 percent rate, the highest it had been since June. It was not immediately clear what explained the fluctuation in the numbers, but a spokesman for the health department said Wednesday that the rate could be influenced by the total number of tests each day.
The seven-day average is a better measure of the spread of the virus over time, officials have said.
The mayor has said that he will automatically shut down public school classrooms — which are all slated to be open by Thursday — if the test positivity rate exceeds 3 percent over a seven-day rolling average. On Tuesday, he said the seven-day average was 1.38 percent.
“We were the epicenter,” Mr. de Blasio said Wednesday. “We fought back. Testing was crucial. We have a problem now, we’re going to overcome the problem. I have no doubt we’re going to beat it back.”
Officials said the city on Wednesday was sending 400 police officers, 300 members of the city’s test and trace program and 250 other employees to the target neighborhoods to distribute masks, step up outreach and education about the virus and crack down on people and businesses violating public health rules.
“Almost 1,000 city employees will be out in these target ZIP codes,” the mayor said.
The city is also trying to ramp up testing in the neighborhoods.
The figures come at a particularly crucial moment, as the city tries to fully reopen public schools this week for in-person learning to hundreds of thousands of students in addition to resuming indoor dining at 25 percent capacity on Wednesday. The restaurant industry, battered by the pandemic, is hoping indoor dining will help ease months of hardship.
“It’s crucial to bringing back more jobs and helping businesses to survive,” Mr. de Blasio said. “But health and safety, as always, come first.”
Those ZIP codes made up 23 percent of all cases in the state, he said, but only represent 6 percent of the overall population. Statewide, the daily positivity rate was 1.02 percent, the governor said. On Monday, the governor reported that the statewide rate was approximately 1.58 percent — a jump from results reported on Sunday and in prior weeks.
“If you don’t control a cluster, a cluster becomes community spread,” he said.
In New Jersey, Gov. Philip D. Murphy said Wednesday that the state’s daily positivity rate was 3 percent, the highest since July.