People who are severely immune-compromised should consider getting a third dose of a COVID-19 vaccine, several members of a federal advisory committee said Thursday, and should definitely take other precautions like wearing masks and making sure those around them are vaccinated.
The Advisory Committee on Immunization Practices (ACIP), which doesn’t have the regulatory authority to officially recommend a third shot, presented data at its meeting Thursday that suggested a booster shot was unlikely to cause harm and might benefit someone who is significantly immunocompromised because of cancer or on powerful medication to prevent autoimmune reactions or organ rejection.
“There is sufficient data to suggest that an additional dose would be helpful,” said Dr. Grace Lee, a committee member and professor of pediatrics at Stanford University School of Medicine in California.
In four small studies of transplant and dialysis patients who did not develop antibodies in response to two shots, 33% to 50% developed them after a third.Lee said she hoped federal agencies would monitor people who receive a third dose to ensure these shots are safe.
The Centers for Disease Control and Prevention has said that booster shots are not yet needed by the general public, because people continue to be well protected by their initial shots. Currently, 97% of those hospitalized with COVID-19 were not vaccinated, according to the CDC.
While vaccines protect more than 90% of healthy people from getting symptoms of COVID-19 and even more from getting seriously ill, the shots are less protective for those with cancer, particularly blood cancers, people taking immunosuppressive medication and transplant patients.
People who are immunocompromised are at above-average risk for becoming severely ill if they catch COVID-19, Dr. Sara Oliver, with the CDC, told the committee. They are also more likely to transmit the virus to people they live with. And more than 40% of those hospitalized with COVID-19 after being vaccinated are immune-compromised.
About 2.7% of the population — or 900,000 Americans — are immunocompromised, she said.
Some immune-compromised patients are already getting booster shots on their own, without being studied or watched to make sure they are safe, Dr. Dorry Segev, a transplant surgeon and researcher at Johns Hopkins Medicine,who is not connected with the committee said after the meeting.
“Anytime you give someone a vaccine, you are trying to activate their immune system,” Segev said in an interview. In a transplant patient, activating the immune system could damage their donated organ, despite drugs aimed at keeping the body from rejecting it. The first two COVID-19 vaccine doses appear to be safe for transplant patients, but only a few dozen patients have been followed so far after a third.
Blood cancer patients also appear to be able to take the first two COVID-19 vaccine doses safely, said Dr. Gwen Nichols, chief medical officer of the Leukemia and Lymphoma Society, a research and support group.
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But it’s not yet clear whether a booster shot will be safe and effective for those with leukemia, lymphoma or multiple myeloma, she said.
“We all ought to act unvaccinated, especially blood cancer patients,” she said. “Continue to avoid places where you can’t control your environment. Don’t let people shame you from wearing a mask.”
In a study of 1,500 blood cancer patients published online Thursday, 75% mounted a measurable immune response after getting both doses of the vaccine, but 25% did not.
Many of the patients who did not make antibodies were not in active treatment, suggesting their disease, not their treatment, undermines their immune response, said Nichols, whose organization is still seeking volunteers for its registry of vaccinated patients.
It’s not clear what level of antibody is protective against infection or severe disease. The immune system has other means of defense in addition to antibodies, so just because someone doesn’t have antibodies doesn’t mean they are completely unsafe.
Plus, antibody levels decline over time, while protection from vaccination seems to remain strong at least for 6-12 months. And antibody levels are recorded differently by different tests.
That’s why the CDC discourages people from checking their antibody levels to decide if they are adequately protected.
But Segev said he uses antibody tests to screen enrollees in his research trials, hoping to identify those who most need a boost. To join one of his trials, a patient has to have no detectable antibodies or measure fewer than 50 units per milliliter more than a month after two shots of Pfizer or Moderna’s vaccine, using the Roche Elecsys anti-Receptor Binding Domain (RBD) assay.
Segev recently received a $40 million grant from the National Institutes of Health to study ways to better protect kidney transplant recipients.
He expects to enroll the first patients next month in a pilot study at Johns Hopkins and then expand it nationwide.
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It’s crucial, Segev said, to track patients as they try different protective approaches to ensure that they are safe and that others can learn from their experiences.
Dr. Jason Goldman, who represented the American College of Physicians at Thursday’s meeting, said he saw six COVID-19 patients in his clinic Wednesday, all vaccinated, as well as a newborn, who had been infected by an unvaccinated family member.
“I worry that boosters will not be any more effective in the immunocompromised than in the initial series (of shots),” said Goldman, who practices in Coral Springs, Florida. “We need to stress the importance of creating a circle of protection for ourselves and our family, friends and loved ones… by making sure everyone gets vaccinated.”
Contact Karen Weintraub at [email protected]
Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input
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