On Wednesday afternoon, Borough Park was abuzz with the rituals and routines of the Jewish High Holidays. Families inspected lulav and etrog on the corners of 13th Avenue, the bustling commercial strip in the heart of the neighborhood, and hoisted temporary walls onto balconies for next week’s festival of Sukkot. Live chickens clucked in stacked cages, soon to be slaughtered as part of the annual pre-Yom Kippur atonement sacrifice.

Across the neighborhood, men of all ages, almost none of them wearing masks, hustled into crowded synagogues to pray.

The previous evening, the city's Health Department alerted New Yorkers to an alarming uptick in COVID-19 cases in Brooklyn’s ultra-Orthodox neighborhoods, warning that it could “evolve into more widespread community transmission and spread to other neighborhoods unless action is taken.”

Mayor Bill de Blasio, who faced criticism for his handling of past COVID outbreaks in Hasidic neighborhoods, promised a swift mobilization of community outreach and enforcement on Wednesday morning. “The Sheriff's Office will be involved,” he said. “NYPD will be involved as well. This situation will lead to immediate actions today.”

Borough Park residents we spoke with said they’d seen no sign of an added police or public health presence in the area by Wednesday evening. Few seemed aware of the growing rate of transmission among their neighbors.

“Is that right? I hadn’t heard,” said Zvi Abramovitz, a 20-year-old employee of Mostly Music, a shop specializing Judaic media. “I think almost every single person already had it. Right around March when the virus was really bad, a lot of people I know passed away. But that’s over.”

Eichler's bookstore in Borough Park on Wednesday

Borough Park, Midwood, and Bensonhurst are now reporting a coronavirus testing positivity rate of 4.71 percent — far higher than the citywide average, which continues to hover around 1 percent. The neighborhoods of Williamsburg, Far Rockaway, and Kew Gardens have seen recent upticks as well. The six neighborhoods now account for 20 percent of new cases in the city.

Inside Shomrei Shabbos, a 24-hour synagogue that’s long served as a neighborhood meeting point, unmasked congregates filtered into a narrow hallway to wait their turn to pray in a crowded room. “I was the only one here of 20 people wearing a mask,” said 70-year-old Chaim Krieger. “It’s just not central to their concern.”

Sam Stauber, a 57-year-old man who said he caught the virus months ago while praying at Shomrei Shabbos, blamed the mayor for not doing enough to inform the community of the recent uptick. “There should be someone talking about it,” he said. “People aren’t taking it serious, like I didn’t take it serious the first pandemic.”

13th Avenue on Wednesday afternoon

Residents said that weddings, funerals, and other large indoor events had continued unabated through the summer and early days of fall. Several people reiterated their belief that local residents attained herd immunity this past spring, when the virus devastated New York's ultra-Orthodox community, claiming an estimated 700 lives across the state.

“The first time was bad because people weren’t cautious enough,” said a barista at Milk Crate, a kosher cafe 49th Street, who declined to provide his name. “Ninety-five percent of people here have antibodies.

According to the most recent available data provided by the city, 44.3 percent of Borough Park residents tested were shown to have positive antibodies, the second highest rate in the city after Corona, Queens. That number is still well below the minimum threshold that many experts believe is necessary for herd immunity.

Dr. Denis Nash, a former CDC and city Health Department epidemiologist, now a professor at the CUNY School of Public Health, said it would be unwise for communities to embrace the notion of herd immunity as protection against the virus.

"Someone from the city needs to communicate two things to them: we don't know that antibodies provide protection, and herd immunity doesn't apply to communities where there is a lot of in and out migration," he said, alluding to relatively frequent travel between New York City neighborhoods, the suburbs, and other parts of the world.

Ahead of last weekend’s Rosh Hashanah observances, the New York State Health Department issued guidance for Jewish prayer services, reminding everyone to wear face-coverings during prayer and to keep synagogues at less than 33 percent capacity. The document goes so far as to recommend a surgical mask be placed over the wide end of a Shofar, a religious horn used this time of year, when blowing it indoors.

Data has shown that houses of worship are hotspots for super-spreader events, particularly when congregants are singing or chanting in close quarters. Some ultra-Orthodox sects, including the Chabad-Lubavitch movement, have encouraged elderly and immunocompromised adherents to pray at home.

Listen to Fred Mogul's report about the cluster on WNYC:

But with some exceptions, residents said that rabbinical leadership in Borough Park had done little to encourage social distancing, mask-wearing, and other mandated COVID protections. The concerned community members, who asked for anonymity for fear of public backlash, pointed to silence from religious leaders, as well as deep support for President Trump within the Haredi community, as reasons for the apparent lack of concern.

“They’re exposed to nonstop right-wing media,” said one Hasidic physician. “There’s no competing ideology.”

The doctor said he'd resigned himself to a second wave, which he expected to build throughout the holidays, peaking sometime this winter.

“I feel like I’m living in the Twilight Zone a little bit,” he added. “The ship has sailed. We’re headed toward another super spreading event.”

Additional reporting by Fred Mogul.