Trash lines the streets in many New York City neighborhoods last week.
CNN  — 

Uncollected trash has piled up in parts of New York City as the Department of Sanitation has dealt with a delay in service and staffing issues, officials said Monday.

“Yes, we did experience a delay in a service, a gap, we were making up for throughout [last] week,” said department Commissioner Edward Grayson.

“Ours is a very visible service to all New Yorkers as we all know – so, with 12,000 tons coming out every single day in the residential areas, once you get a little behind, it’s going to take a little while to right the ship. We had full staffing in place throughout the weekend; we did work the extra service day on Sunday to do the best we can to catch up.”

As of Monday, the backlog had been cleared.

“Sanitation services are continuing across the City,” department press secretary Vincent Gragnani told CNN in an email. “Our Sanitation Workers were moved to 12-hour shifts last Thursday, and they will continue with those shifts to keep our city streets clean and safe. They will also be working Sundays, as needed, including yesterday.”

The issues with trash pickup come at the start of a Covid-19 vaccine mandate for all New York City employees, including workers with the sanitation department.

New York is one of only a number of US cities dealing with trash collection issues. Broadly, the pandemic has created a labor shortage in a range of critical fields across the country, and these shortages have significantly impacted trash and recycling collection in Jacksonville, Florida; Atlanta; and Denver, Colorado, among other cities.

“Both public and private sector collection service providers are facing increased difficulty hiring and retaining collection truck drivers and helpers,” reads a May 2021 report from the Solid Waste Association of North America, an organization made up of about 10,000 industry professionals. “Some waste and recycling collection service providers are having difficulty providing services at pre-COVID-19 service levels.”

Despite the issues, New York City data indicates the vaccine mandate has effectively pushed many unvaccinated city workers to get the shot.

As of October 19, 62% of city Department of Sanitation employees had received at least one dose of the vaccine, but that number has jumped to 83% as of Monday morning, according to Gragnani.

Commissioner Grayson said the number of vaccinated people in the department has continued to increase by the day.

“The mandates have put us back into a very healthy position,” he said Monday.

All city employees were required to show proof of Covid-19 vaccination by Friday, October 29. Those who have not been vaccinated were expected to be placed on unpaid leave, the city said.

Mayor Bill de Blasio said about 9,000 city employees are on unpaid leave as of Monday, out of a workforce of 378,000, for not complying with the mandate. About 12,000 city employees have applied to receive religious or medical exemptions and the city will be responding to these inquiries in the coming days, he said.

De Blasio said there have been no interruptions in service for the police, fire department or Department of Sanitation, but he acknowledged there was a high number of workers claiming to be sick and missing work.

“We have every reason to believe there’s a lot of people out there claiming to be sick who are not and it’s not acceptable,” he said. “So the thing to do is to do the right thing. Come to work, protect people as you took an oath to do.”

CNN’s Artemis Moshtaghian, Melanie Schuman and Evan Simko-Bednarski contributed to this report.