Shoppers wait in line to enter a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

As senior citizens deal with anxiety about the coronavirus, grocery store chains and other retailers have come up with a way to ease their fears: shopping times reserved exclusively for them.

Target, Whole Foods, Walmart and Dollar General, as well as supermarkets in Europe, began dedicating early morning times for older customers this week. The theory is that allowing seniors to shop among smaller crowds could reduce their chances of acquiring the virus and give them first crack at buying hand sanitizer and other products that have been hard to find because of panic shopping.

The idea seems to have worked well in smaller shops but backfired in some larger stores, where big crowds made "social distancing" difficult.

"If you didn't have coronavirus before you got there, you probably do now," said Roger Glenn Miller, 82, after he showed up Thursday morning at a Stop & Shop grocery in North Providence, Rhode Island, along with about 200 other seniors.

Don Gregson, 81, had a similar experience at the same Stop & Shop. Gregson said he expected to shop with a small group of seniors but instead found aisles crowded with people.

When he saw the number of people in the store, Gregson slipped on a surgical mask he carries in his pocket, then bought 4 gallons (15 liters) of distilled water for the machine he needs for sleep apnea.

Roberta Miller, 74, looks for hand sanitizer at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

"I'm sure they were trying to do the right thing, but somehow the planning went astray," he said.

The Massachusetts-based chain, which is offering the special shopping time for seniors every day, said in a statement that it is asking its customers to consider staggering the days they shop "to ensure a less crowded environment. as well as for everyone to exercise caution and social distancing while shopping."

Ernest Hodge, 72, had a much smoother experience at a Dollar General store just north of Richmond. Hodge showed up at 8 a.m. sharp Wednesday, wearing a face mask and blue rubber gloves to protect himself. He was able to shop among just a half-dozen other seniors and got most of what he needed, including disinfecting wipes, spray cleaner and bottled water.

Hodge said he was happy when he heard about the special shopping hours because he is trying to limit his exposure to people.

Wade Warner picks up a toilet paper roll at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. Some items were still on back order while workers were restocking meat and produce this morning at the store. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. (AP Photo/David Goldman)

"I get off work, I go home. I don't come out again unless it's a must," he said.

Dollar General is reserving the first hour of shopping every day for seniors at its more than 16,000 stores. Target has set aside an hour every Wednesday morning for vulnerable shoppers, including the elderly and those with underlying medical conditions. Walmart said it will host an hourlong " shopping event" every Tuesday for customers 60 and older, one hour before stores open to the general public.

In South Africa, the supermarket chain Pick n Pay said this week that it will open all its markets an hour early every Wednesday for shoppers over 65. And Sainsbury's, one of the largest supermarket chains in the United Kingdom, reserved the first hour of shopping in its stores Thursday for elderly and other vulnerable customers.

A shopper wears gloves upon entering a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

Jim Gibson, 72, from Crofton Park, southeast London, went to his local superstore in Bell Green, where he said he had a "relatively trauma-free" experience except for the fact that some younger shoppers appeared to ignore the request to reserve the hour for .

Most of the products he was looking for were there, though many canned items were "leaping off the shelves" and he couldn't get the medicines that he and his 73-year-old wife want "for love or money."

For most people, the new causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing , it can cause more severe illness, including pneumonia. The vast majority of people recover.

The outbreak has caused more than 10,000 deaths out of nearly 245,000 cases worldwide.

  • Shoppers wait to enter a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • A worker restocks the meat section of a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • Shoppers wait in the checkout line at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • Lorraine Smith, 79, left, talks with a fellow shopper at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. "My husband is disabled and we have an aide the comes in everyday but he needs it. I just get nervous," said Smith of the virus' contagiousness. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • A shopper looks for toilet paper at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. Some items were still on back order while workers were restocking meat and produce this morning at the store. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. (AP Photo/David Goldman)

  • Larry Eleoff, 70, left, looks over his list while waiting in the checkout line at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. Eleoff was able to get most of the items on his list. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. (AP Photo/David Goldman)

  • Nancy Pesapand, 92, center, grabs bananas as a worker restocks the produce section of a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • A shopper puts on gloves before entering a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • Roberta Miller, 74, loads her items at the checkout at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • In this Wednesday, March 18, 2020, photo, Ernest Hodge, 72, wears a face mask and rubber gloves as he loads groceries into his car outside a Dollar General store in Glen Allen, Va., north of Richmond. Dollar Tree, Target, grocery store chains and other retailers are offering special shopping hours reserved for senior citizens and other populations that are particularly vulnerable to the new coronavirus. (AP Photo/Denise Lavoie)

  • Don Gregson, 81, loads what was left of distilled water jugs into his car after shopping at a Stop & Shop supermarket during hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. Gregson needs the water for his CPAP machine which helps with his sleep apnea. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

  • Chris Moshier, customer service manager, opens the doors to shoppers waiting at a Stop & Shop supermarket for special hours open daily only for seniors Thursday, March 19, 2020, in North Providence, R.I. This week grocery store chains and other retailers began offering special shopping hours for seniors and other groups considered the most vulnerable to the new coronavirus. The dedicated shopping times are designed to allow seniors, pregnant women and people with underlying health conditions to shop among smaller crowds and reduce their chances of acquiring the virus. (AP Photo/David Goldman)

William Petri, a professor in the University of Virginia's Division of Infectious Diseases and International Health, said setting aside dedicated times for seniors to shop makes sense.

Petri said health officials have found that many people who are infected don't have symptoms right away but are still infectious.

"That's an even better reason to try to isolate those who are most vulnerable, like the elderly, from younger people through dedicated shopping hours," Petri said.

Better yet, Petri said, would be for seniors to get groceries delivered to their homes.