For years, Jen Rosen’s upscale intimates shop in Center City specialized in fitting women for bras.

When the COVID-19 pandemic hit last spring and confined thousands of Philadelphians to their homes, stiff bras became anathema — the enemy of comfort.

“There was a point in the pandemic where people were not wearing bras,” Rosen said, so she ordered sweatshirts, sweatpants, and other cozy lounge wear for her store, Je Suis Jolie (formerly known as Hope Chest), at 114 S. 19th St. in Rittenhouse Square.

Even so, business was slow for months.

In recent weeks, as vaccinations have become readily available — all adults are now eligible — and the weather has warmed up, the liveliness of Rittenhouse Square has begun to resemble what it was pre-COVID, merchants and business advocacy groups jubilantly say.

“We have seen a big jump in the last two to three weeks,” Rosen said. “There’s double the traffic. The weather’s getting nicer, but the vaccinations really are a huge factor.” With that, she said, “now people are ready to wear bras again — and real clothes.”

The Center City District, a promotional organization that oversees 233 blocks and provides security, cleaning, and marketing, recently reported more pedestrians in Center City in the first week of April — at a daily average of 103,296 — than at any point last year.

“From my observation, people are coming back,” said Barbara Halpern, vice president of community outreach for the nonprofit Center City Residents’ Association. “The streets look a little busier, and the merchants are really happy when you come in the store. What can you say? I’ve never seen them happier to see me.”

Center City, which supported 42% of jobs in Philadelphia in 2019 and has been one of the city’s biggest economic forces, suffered a significant blow during the pandemic as thousands of office employees abruptly began working from home.

The neighborhood’s restaurants and retailers, accustomed to a steady flow of patrons, suffered. As the worker population in Center City shrank by 76%, office occupancy in the area’s business district also decreased by 1.2 million square feet, taking the vacancy rate from 15.4% in the last fiscal quarter of 2020 to 16.2% in the first quarter of 2021, the Center City District found.

» READ MORE: Pandemic office closures in Philadelphia mean peril for lunch spots and stores (from June 2020)

By late March of this year, the number of visitors and shoppers in Center City had grown to 141,000, the district said — still 70,000 fewer people than the 215,000 visitors in the January before the pandemic started, but leagues more than the paltry figure of less than 50,000 last April. The number of office workers dropped from 168,000 in January 2020 to 59,000 last month.

Hotel tax revenue fell to a low of $400,000 each month last May and June, compared with $7 million and $8.2 million in those same months in 2019. Out of Center City’s 1,916 businesses with storefronts, 101 businesses in Center City had shut permanently as of January.

Retailers — particularly small businesses — struggled quietly. George Patti, the owner of Head Start Shoes, a family-owned footwear store at 126 S. 17th St., said in December that he was down to selling just one or two pairs of shoes a day.

To the relief of restaurateurs, the competitive restaurant industry in Center City has been on the upswing, thanks to outdoor dining. The number of outdoor seats grew from 3,654 in February to 4,406 in March, according to the Center City District. About the same time, the city also allowed restaurant-heavy corridors to be closed to vehicle traffic to maximize the number of people who wanted to dine on the street.

That initiative, which has attracted a surge of restaurant-goers, has hurt business at Sherman Brothers Shoes, a family-owned business that has sold high-end formal shoes at 1520 Sansom St. since 1967, said Ken Sherman, who runs the store with his brother Jeff.

The 1500 to 1600 blocks of Sansom Street are closed to cars every day from 4 p.m. to midnight for outdoor dining. Sherman said it has reduced foot traffic and left customers to wonder whether his business is still open. It also has curtailed trash pickup, a service he still pays for, because the trash truck can’t drive down the street.

“I walk my trash 10 blocks to where I park,” he said. He then drives his garbage home, where he throws it out.

Despite a bevy of concerns that also included unruly diners who have urinated and vomited on Sherman’s property at night and broken a window, he acknowledged that he “can’t fight every battle” and wants to be patient. He repeatedly expressed gratitude for his customers, some of whom have become his friends.

“We all have our crosses to bear here, and I do try to look at the bigger picture,” Sherman said. “I want all these restaurants to survive. I want all of us to survive.”

As diners have returned in volumes, another promising sign has been widespread hiring among Center City restaurants, said Corie Moskow, executive director of Rittenhouse Row, a nonprofit that acts as the Chamber of Commerce for merchants in Center City.

“That’s a good sign,” she said. “That’s a good thing. … The tourists are beginning to return.”

Moskow noted that some businesses severely damaged during civil unrest stemming from the killing of George Floyd last May also were reopened recently. Marathon Grill, at 121 S. 16th St., which sustained heavy damage, was reopen at the end of March. Philadelphia Runner, at 1601 Sansom St., is expected to reopen by June, after the store was ransacked and set on fire last year.

Add to it a couple of new businesses to Center City’s most popular retail corridors, said Moskow and Paige Jaffe, managing director at the commercial real estate firm Jones Lang LaSalle. They include the sustainable shoe store Allbirds; Govberg Jewelers, which is slated to open next month; Tiffany’s, which moved from South Broad Street to 1715 Walnut St.; Atmos, Interior Define, Kate Spade New York Outlet, and Kevin O’Brien Studio.

Some small businesses have managed to hang on in Center City — and the owners who own their property have a leg up, Moskow said.

“As their own landlords, they’re really not going anywhere, which is awesome,” she said, pointing to Richard Nichols Hair Studio, the designer clothing store Joan Shepp, and Kimberly Boutique as examples. “All this fear that retail is crashing and burning, which it is internationally — but we do have some operators here, and although it’s harder than they wanted it to be, they’re not quitting. They’re not leaving. It’s their family legacy.”

» READ MORE: Allbirds pushes for more brick-and-mortar stores even during COVID-19

With her own small business, Rosen said she and her staff have fought to keep Je Suis Jolie — French for I am pretty — afloat. Next to coping with a significantly smaller number of customers, they had to deal with limited options from vendors, who Rosen said dropped certain styles and colors completely.

“I think they’re just not cutting as many pieces because they can’t afford it, and they don’t want to front the money in case it doesn’t sell,” she said. “Basically, the lines are a lot tighter. There’s not as much stuff to pick from.”

Rosen ordered what she could, created an e-commerce platform, and posted more on social media. Business eventually began to pick up.

In that time, Rosen acknowledged yet another thing that had changed: herself.

She began taking pictures of herself in merchandise and posting them to social media during the pandemic, so she could connect better with customers, she wrote on Instagram. “While the photos you see on [Instagram] may look comfortably effortless — it took a long time to have the confidence to even press the ‘post’ button. The struggles of the past year have taught me to stop trying to be skinny and instead thrive to be strong.”