Bread, milk, flu shot: Taking care of all your necessities with one-stop shopping is enticing. So it may seem like a boon to the road-weary that pharmacies and grocery stores increasingly offer flu shots within view of the deli or dairy case.

But is there a difference between rolling up your sleeve at the doctor’s office — which may be bursting with sick people— and getting a flu shot in the middle of the cough syrup aisle?

Influenza vaccinations must still be administered by licensed health-care professionals – typically nurses or pharmacists. But where they do the deed apparently isn’t nearly as important as simply getting it done, experts say.

“It’s a good idea, obviously with the proviso that it’s done according [to] a standard of practice,” said Dr. Gregory Poland, director of the Mayo Clinic’s Vaccine Research Group. “It’s convenient, it makes it easier for whole families to come in, and in the context of a trip to the grocery store, they can have this done.”

Poland participated in a panel that advised the U.S. Centers for Disease Control and Prevention (CDC) last year to recommend that all Americans over 6 months of age receive the flu vaccine. That amounts to 296 million people, and he said he has few qualms about where people are immunized. The long list of chains now offering flu shots include Walgreens, Target and CVS, where the vaccinations typically cost between $20 and $30.

Between 5 percent and 20 percent of people who aren’t vaccinated will develop flu infections, Poland said.

Rising rate of drugstore vaccinations

About 129 million doses of vaccine have been distributed this season, according to the CDC, and there is plenty of time to jump on the bandwagon: Flu season typically peaks in January and February. This year’s vaccine protects against three different strains, including H1N1 (also known as the swine flu), the emergence of which spurred a national panic two years ago.

In fact, the 2009 H1N1 epidemic spurred customers turning to drugstores, which often had vaccines left after doctors’ offices had depleted their supplies, according to the National Association of Chain Drug Stores.

While medical settings such as doctors’ offices account for about 55 percent of all flu shots given this season, according to the CDC, about 21 percent have been administered at commercial locations such as pharmacies, grocery stores and other stores — a jump of 3 percent since last year. Other locations include workplaces and schools.

“The upside of having the shot available in more places is it increases vaccine-administration rates,” said Dr. Joel Mendelson, director of allergy and immunology at Newark Beth Israel Medical Center, in New Jersey.

“I really can’t think of a significant downside,” Mendelson said. “And pharmacies are a natural place, because these are some of the places the high-risk people come — diabetics come there for insulin, asthmatics come for inhalers.”

It seems a win-win for pharmacies and supermarkets to offer vaccines: While analysts have debated just how profitable the practice itself is, there’s no question that it increases sales of other items to customers who consolidate their errands. Some insurance plans pay for immunizations — which are listed as “preventive care” — no matter where they are received, while others stipulate the shots must be given in a medical setting. But if an office co-pay must be met, it may be cheaper and easier (no appointment required) to get a flu shot while you’re picking up dinner fixings.

A standard protocol for administering the injection is observed no matter where flu shots are offered, Poland and Mendelson said. All who seek the vaccination (or, for children, their guardians) must first fill out a questionnaire that, among other things, explains who should not receive the shot – namely, people severely allergic to eggs (in which the vaccine is grown).

Because the flu vaccine is overwhelmingly safe, Poland said, the protocol of having a questionnaire negates most potential problems. That said, “I would have more concern about the place where infants receive vaccines,” he said, “primarily because if something did happen, almost nobody in that [supermarket] setting is prepared to treat or resuscitate an infant.”

Bad reactions

Mendelson noted that the rate of “immediate reactions,” in which a person suffers a negative medical reaction just after a shot is administered — including potentially fatal anaphylactic shock — is “exceedingly low,” happening only once in every 1.5 million vaccinations.

“Pharmacists dispense drugs every day that have much higher reaction rates when people take them home – like antibiotics,” he added.

But one of the tradeoffs of getting a flu shot outside of the doctor’s office is that it can disrupt the doctor-patient relationship, Poland said, causing doctors to miss the chance to intervene on other medical matters while giving simple immunizations.

“If you go to the grocery store and get a flu vaccine, that’s great,” Poland said. “But they’re not saying to you, ‘You need to lose weight . . . you also need the pneumococcal and pertussis vaccines . . . you haven’t had your screening for colon cancer or your mammogram.’ There’s always that.”

Pass it on: It’s generally safe for most people to get their flu shot at a pharmacy or grocery store, though experts say infants should be not immunized in such settings.