The Food and Drug Administration is speeding efforts to authorize extra doses of the coronavirus vaccines for Americans with weakened immune systems, a change that reflects a growing concern within the Biden administration about these vulnerable patients as the contagious Delta variant surges nationwide.
The regulatory move would mean that people with impaired immune responses who need an extra shot, such as certain cancer patients, would be able to get one legally. That is a safer alternative than patients seeking shots on their own, as many now do, several experts said.
“The data are unequivocal that they have not gotten a good response to begin with” and need additional doses, Dr. Anthony S. Fauci, lead medical adviser to the White House on the pandemic, said in an interview on Friday.
Compared to other Americans, “there is much, much more of a compelling reason to do that sooner rather than later,” he said.
The benefit of vaccinating these patients may extend well beyond this group. Persistent infection with the coronavirus in immunocompromised people may lead to more transmissible or virulent variants, according to recent research. Protecting these patients may help prevent variants from emerging.
Officials at the Centers for Disease Control and Prevention and the F.D.A. had been exploring special programs to get additional shots to immunocompromised patients. Now the F.D.A. aims to modify the emergency authorizations of at least two of the vaccines, if data from the C.D.C. support such a move, according to two people with knowledge of the discussions.
The move, which is expected this month, was first reported by The Washington Post.
Full approval of the Pfizer-BioNTech vaccine is expected by early September, perhaps even sooner. “If you told me that full approval is expected by February, I would say that’s a long time for immunosuppressed people to wait,” said Dr. Dorry Segev, a transplant surgeon at Johns Hopkins University. “But the next month will bring us a lot of data.”
Dr. Fauci earlier in the week distinguished between booster shots for people who are fully vaccinated but may be seeing waning immunity, for which the scientific rationale is not yet clear, and additional shots for people with impaired immune systems. Research indicates that at least some of the latter group need extra doses.
The World Health Organization on Wednesday decried the move toward booster shots for fully vaccinated people in rich countries, saying poor nations urgently need the extra doses. But officials took pains to add that this criticism did not refer to extra doses for people with weakened immune systems, who may not have been fully protected to begin with.
Since April, France has offered third doses to certain people with poor immune responses, and recently Germany and Hungary followed suit. But in many European countries, the strategy is not limited only to these patients, but includes older adults, for example, or those who received the AstraZeneca or Johnson & Johnson vaccines.
In the United States, at least 3 percent of the population is immunocompromised because of medical reasons like some cancers, organ transplants, chronic liver disease, kidney failure and dialysis, or because of widely prescribed medications like Rituxan, steroids and methotrexate.
With the Delta variant surging, some of these patients, and their physicians, have been pleading with federal agencies to open a regulatory path to third doses. Although advisers to the C.D.C. have long seemed to favor the idea, the F.D.A. had not yet done so.
Older adults and people with some conditions that suppress the immune system are routinely given extra doses of the vaccines for influenza and hepatitis B. That experience provides a sound justification for offering additional doses to some older adults and people whose immune responses are muted, said Dr. Balazs Halmos, an oncologist at the Montefiore Medical Center in the Bronx.
“Being very proactive makes sense to me,” Dr. Halmos said. “I would love to see the F.D.A. quickly making that stand and maybe following these countries in terms of their proactive approach.”
But other experts are more circumspect. Scientists are still unsure which groups of immunocompromised people will benefit from a third dose.
“I think you can justify both positions,” said Dr. Helen Boucher, an infectious disease physician at Tufts Medical Center. “Germany is justified in what they’re doing, but I also feel like we’re justified in hanging back because the information is far from perfect.”
Dr. Boucher says she empathizes with patients who are immunosuppressed. But “the bottom line is we need more information,” she added.
That information has been trickling in far too slowly for some Americans.
Deborah Rogow, 70, has multiple myeloma and is worried about the spread of the contagious Delta variant. Ms. Rogow said having a doctor prescribe a third dose if necessary would have been ideal.
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For the moment, she’s on her own, and so Ms. Rogow plans to get a third dose of the Moderna vaccine next week at a pharmacy in Santa Barbara, Calif. The Moderna vaccine is still far from full approval, she noted, but she did not want to get a Pfizer-BioNTech dose without more data on mixing the two vaccines.
“I definitely would have appreciated if I could have had my doctor say to do it,” she said. “But it’s coming a little too late.”
Additional doses may help some people with weak immune systems, but others may show little improvement even after a third dose, and still others may not need extra doses at all. In a study of organ transplant recipients, only a third of the patients who got a third dose showed a benefit.
“I wish we had a more rational process to identify individuals within these categories who actually need it versus not,” said Deepta Bhattacharya, an immunologist at the University of Arizona.
There are safety concerns with enhancing immunity in patients whose responses are suppressed for a reason. One patient in the transplant study experienced mild rejection of her transplanted heart after receiving a third dose, and recovered, said Dr. Segev, who led the research. Patients who have autoimmune conditions may experience flares when their immunity is enhanced.
“You’re walking this fine line between wanting the immune system suppressed but also needing the immune system activated to get a good vaccine response,” Dr. Segev said.
There is also not much long-term data on people who have received third doses, he noted: “I don’t think there is strong evidence that a third dose is safe yet — there is encouraging evidence.”
In the meantime, he suggests that the safest way for people with weak immune systems to get a third dose is to enroll in research studies where they can be closely monitored.
The coronavirus persists for much longer than usual in some immunocompromised people and has opportunities to make big evolutionary leaps, according to a study published on Thursday in the New England Journal of Medicine.
Some variants now in circulation may have arisen in that way, researchers have said, and leaving people with impaired immune systems unprotected may open the door to more dangerous variants.