Using the vaccine developed by Pfizer and Germany’s BioNTechWalgreens has inoculated hundreds of thousands of Americans against Covid-19 this year. But the pharmacy chain has not been following guidance from federal health officials concerning the timing of second doses.
The guidelines require two doses, three weeks apart. Walgreens, however, separated them by four weeks because it was faster and simpler for the company to schedule appointments.
There is no evidence that separating the doses by an extra week decreases the vaccine’s effectiveness. Even though the Centers for Disease Control and Prevention recommends a three-week gap, the agency says it is acceptable to separate the doses by up to six weeks if necessary.
Walgreens’s decision, however, was never announced publicly and caused confusion for some customers. It also caught the attention of federal health officials. This decision was never announced publicly. Kate Grusich, a spokeswoman for the C.D.C., said the agency asked Walgreens to stop using a longer-than-recommended period between doses.
The company’s vaccine-scheduling system schedules all second doses four weeks after the first, by default. Doses of Moderna’s vaccine, which Walgreens is also administering, are supposed to be spaced four weeks apart, so using the same gap for both vaccines was “the easiest way to stand up the process based on our capabilities at the time,” Dr. Kevin Ban, Walgreens’ chief medical officer, said in an interview.
Walgreens is currently changing its system. Beginning as soon as the end of the week, the pharmacy will automatically schedule people for Pfizer doses three weeks apart, Dr. Ban said.
Walgreens is one of the largest drugstore and grocery store chains that are giving out vaccines allocated by states and via a federal program that the White House said last week would expand to 40,000 locations. Walgreens reported last week that it had given out more than eight million Covid vaccine doses, including four million in March, and expects to give out 26 million to 34 million before the end of August.
Walgreens, along with CVS, previously led an effort to vaccinate nursing homes and other long-term care facilities. The Pfizer doses at those facilities followed CDC guidelines and were spaced three weeks apart.
The vaccination campaign is a business opportunity for Walgreens. It brings in revenue from administering the vaccine from fees paid by the government and private payers as well as from purchases made by shoppers coming in for vaccines. Additionally, it helps their business database by requiring people to create a Walgreens account to search online for a vaccine appointment.
Most of the other major pharmacies, including CVS and Rite Aid, have been adhering to the C.D.C.’s guidance on the timing of second doses. CVS, for example, schedules second Pfizer shots for 20 to 23 days after the first shot, said T.J. Crawford, a spokesman for the chain.
Some public health experts believe the United States should delay the second dose of the vaccines by longer than what Walgreens has been doing with the Pfizer vaccine. It could allow more people to get partial protection through the first shots. Britain, for example, is delaying second shots by up to three months. Canada has begun delaying doses by up to four months.
But it was in fact a three-week gap between doses that underwent extensive clinical testing, and U.S. officials and Pfizer executives have not voiced support for alternate dosing schedules.
It is largely arbitrary that Pfizer’s and Moderna’s vaccines, which both use similar “messenger RNA” technology, have different dosing schedules. Pfizer’s decision to test its vaccine with less time separating the two shots helped the company finish its late-stage clinical trial quickly and report results one week faster than Moderna in November.
Walgreens’ decision to deviate from the C.D.C.’s guidance on dose spacing for Pfizer’s shot left some customers confused. Some assumed, based on their appointment dates, that they would be getting Moderna shots. It wasn’t until they arrived at their appointment that they learned they were getting the Pfizer vaccine.
Some public health experts stated they were not concerned that Walgreens had been scheduling doses with a four-week gap. “It’s a week difference. Everybody’s going to need to put it in their contexts and their risk factors, but I think this is a very reasonable approach” from Walgreens, said Dr. Katherine Poehling, a pediatrician at Wake Forest School of Medicine who sits on the C.D.C. advisory panel that recommended that Pfizer doses be given roughly three weeks apart.
Other experts were not as easily agreeable. “It is not the role of a private, for-profit company to make public health decisions that should be determined by guidelines issued by a public health authority,” said Lawrence Gostin, a global health law professor at Georgetown University.
Dima Qato, a pharmacist and associate professor at the University of Southern California School of Pharmacy, said she was concerned about how the public perceived inconsistent messages about spacing doses of the same vaccine.
“As we’re trying to build trust in this pandemic, I think this may push us back,” Dr. Qato said.
Walgreens is not the only vaccine provider that has been giving second shots slightly later than recommended. Others around the country have been doing so for months, especially in the early days of the rollout. The delays were based upon vaccine supply, which vaccines were available, and how many doses they would be receiving in subsequent weeks, said Tinglong Dai, who studies health care operations at Johns Hopkins University.
The California health system Stanford Health Care schedules all two-shot vaccine doses 28 days apart, with the goal of providing “stability to our patients” while vaccine supply is unpredictable, said Julie Greicius, a Stanford Medicine spokeswoman.
The majority of people in the United States are receiving their second shot when recommended, although more people have been getting it later as the vaccine rollout has expanded.
The C.D.C.’s data through March 28 shows that the percentage of people who got their second shot after the recommended period but within six weeks had increased to 7 percent from less than 3 percent through Feb. 14, according to Ms. Grusich, the agency spokeswoman.