A month after New York City Mayor Bill de Blasio said that all municipal workers must get vaccinated against COVID-19 or submit to weekly testing, the rate of inoculation among this 367,000-member workforce has barely budged.

As of Monday, 58% of city workers—or 211,115 people—have received at least one dose of the vaccines, according to data provided by the mayor’s office. Nearly 13,000 of those city workers got their first shots in the weeks following the mayor's mandate for hospital employees on July 21st and the universal requirement on July 26th.

That’s an increase of just four percentage points in four weeks, a testament to the challenge facing New York City officials as they desperately try to ramp up vaccination rates in the fight against the more infectious delta variant. Under the vaccination-or-test rule, all city workers must comply by September 13th, which is also the first day of public school.

"It’s good to see movement in the right direction, but the delta variant is moving much faster, and these low rates are no match," said Denis Nash, an epidemiology professor at the City University of New York.

The vaccine coverage among city employees is significantly below the 74% of adults citywide who have taken at least one shot. Two doses are needed to maximize protection against the delta variant, but city health officials say 95% of New Yorkers are still following up on their second shots as of this week.

Mayor de Blasio has described the city's approach as "climbing the ladder" or incrementally adding restrictions and incentives such as $100 cash rewards. Demand has doubled recently. Last week ended with 16,000 new recipients per day. Contrast that against a low of 8,200 during the first week of July.

"There's no question that this is having an impact," de Blasio said Monday during his daily press briefing. "I think it's going to have a lot more impact as it affects more and more city workers."

For some, as the mayor has argued, the city’s push has been the difference-maker. Ronald Hickman, a 23-year-old Parks Department employee at Orchard Beach, said last month that he hadn't been interested in getting vaccinated, but after hearing the news from the City Hall, he decided to "just get it out of the way."

Others may be procrastinating, given that the deadline is nearly a month away for most city employees, except those in healthcare settings. But Mark Levine, the City Councilmember who chairs the health committee, worries that the slow pace could signal that some people's feelings have hardened toward the vaccines.

On Sunday, John, a 45-year-old sanitation worker from Staten Island who declined to provide his last name, was among a crowd of roughly 200 people who participated in a protest in front of Gracie Mansion against the city's vaccine requirements. Starting this week, those rules also cover certain indoor activities like dining, gyms and museums.

Joined by his wife and three children, they each took turns holding hand-scrawled signs, one of which said: "I am a free American, not a science experiment." John said he viewed the optional rule for city workers as a precursor to a full vaccine mandate, which he said he and other city workers were prepared to fight with a lawsuit.

In late July, the U.S. Justice Department wrote that public organizations and private companies could legally require the COVID-19 vaccines even though the drugs are still under emergency use authorization. Federal regulators are reportedly expected to issue a full approval in early September, given the vaccines are overwhelmingly safe and effective.

"It's obvious we don't particularly want to do this right now," John said. "We should be given that choice. I think it's our right as an American not to have to take this if we don't want to."

He attributed his vaccine distrust to its seemingly short development time of less than a year, a view often echoed by New Yorkers opposed to the shots. Experts have pointed out that drug developers had a more than a decade headstart with COVID-19 vaccines via ongoing research into two other coronaviruses: Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). That plus more than $10 billion in federal investment under President Donald Trump’s Operation Warp Speed has been credited with spurring the creation of the latest vaccines.

City officials provided their latest data on vaccine coverage in two bins: Health + Hospital employees and everyone else. About 3,800 H+H workers have been vaccinated since their requirements began, going from 58% to 67% with at least one dose. Among non-H+H city workers, the tally is closer to 9,000 initial shots, driven primarily by the Department of Education, NYPD and the Parks Department, officials said.

“The overall vax rate for these workers increased from 53% to 56% over this time,” they added. The city's workforce number—367,000—includes seasonal employees, which can change here and there as people come in and out of public service. The Parks Department and Department of Transportation tend to see staffing boosts in the summertime.

The city did not otherwise offer vaccination rates broken down by agency—numbers that have been hard to come by. In late July, the Department of Education reported that 60% of its workforce had received at least one vaccine shot, though it is not tracking shots delivered outside the city. Similarly, the NYPD said that it had administered shots to only 43% of its members around the same date.

Nash from CUNY said that ideally, the city should have established weekly vaccination targets for each agency so that health officials can identify and address specific shortfalls.

Levine added that the city should, at a minimum, move toward a full vaccination mandate for public school teachers as Chicago and Los Angeles have done.

"Our understanding of the threat of delta has come into sharper view since July," Levine said. "More aggressive measures are clearly warranted."