If asked to show her vaccine card, Stacey Ricks can choose from three.
Ms. Ricks, 49, a kidney transplant recipient who takes immune suppressing medication, didn’t develop antibodies after her first two Moderna shots.
In June, without disclosing she already had received the Moderna shots, she got a dose of the Johnson & Johnson vaccine before federal health officials had approved anyone for a third shot.
Getting her fourth and fifth shots was trickier. By July, pharmacy records in the Houston area where she lives finally showed her prior shots. Armed with a doctor’s note explaining that she hadn’t developed antibodies, Ms. Ricks convinced a pharmacist to give her two doses of the Pfizer vaccine over the summer.
“She kept saying, ‘There’s no clinical data here,’” Ms. Ricks recalled. “And I said, ‘Hey, I am the clinical data.’”
Ms. Ricks is one of many people with compromised immune systems in the U.S. who have sidestepped government guidelines and received unauthorized fourth or fifth shots.
The Food and Drug Administration and the Centers for Disease Control and Prevention are in charge of determining when additional doses should be administered, but some patients and their doctors feel that federal agencies have acted too slowly to protect the most vulnerable.
Israel has already begun rolling out fourth shots — Prime Minister Naftali Bennett announced on Sunday that the country would offer additional shots to people age 60 and over, as well as to medical workers, becoming the first country to roll out an additional booster so broadly.
By comparison, the C.D.C. updated their guidelines in late October to say that immunocompromised groups would be eligible for a fourth dose six months after a third. For those who followed the rules, the earliest eligibility for a fourth would be in late February.
But as new variants like Omicron arise and vaccination rates continue to be sluggish in many areas, worrying those with weak immune systems, many of them are getting extra shots without being certain of whether they are safe or effective.
Typically, doctors have discretion to use approved medications outside of their recommended uses — so a fully approved vaccine like Pfizer’s could normally be prescribed as doctors see fit.
But, in order to receive and administer any Covid-19 vaccines, providers must sign a legal agreement with the C.D.C. — meaning that if they break the agency’s rules, they risk being kicked out of the vaccination program and could face prosecution. The C.D.C. also previously warned that providers administering unapproved shots may not have protection from patients’ legal claims if something goes wrong.
Legal experts say the government has done little to enforce compliance with regulations and seems unlikely to pursue punishments for most providers.
People taking the extra shots aren’t doing anything illegal. They could face civil lawsuits if vaccine providers decide to go after them for lying, but that is extremely unlikely, according to Govind Persad, an assistant professor at the University of Denver Sturm College of Law.
The F.D.A. and C.D.C. did not respond to questions.
Getting extra shots seems to have worked for some — to a degree. After Ms. Ricks’s fifth shot, her doctor sent her a note stating that she had developed a “moderate” antibody response but “still not a typical response.” She has continued taking extra precautions as if she is unvaccinated.
Researchers say some immunocompromised people — depending on their condition and the medications they take — may never generate an immune system response, no matter how many shots they receive. Doctors and advocates for the extra doses say the United States has a surplus of vaccines, so the alternative is often letting them go to waste.
Higher levels of antibodies seem to correlate to better protection against the virus, but researchers aren’t sure exactly what level of protection different numbers of antibodies provide, and the F.D.A. does not recommend that people use antibody tests to gauge immunity.
The C.D.C. estimates that there are around seven million immunocompromised individuals in the country, but it’s difficult to know who will benefit from additional doses, according to Dr. Robert Wachter, chair of the department of medicine at the University of California, San Francisco.
“This is, at this point, probably more improv than science,” he said.
With the blessing of his transplant team, Chris Neblett, who recently moved to Indiana, Pa., got a third shot in April.
Mr. Neblett, 44, had no idea whether it could help him — the medications he takes for his kidney transplant suppress his immune system and stopped him from generating antibodies after two shots of the Pfizer vaccine.
“Sure, we were skirting the rules, but what were the repercussions? There weren’t really any,” he said.
He generated low levels of antibodies after his third shot…