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Immune-Compromised ‘Absolutely’ Should Boost COVID-19 Vaccine Doses

Holidays and Winter Flu Season Put Cancer Patients, Transplant Recipients and Others at Higher Risk for Deadly Viruses, Cedars-Sinai Experts Say

Patients whose immune systems are weakened due to cancer, organ or bone marrow transplants, chronic diseases, or the medications used to treat these conditions may feel like they have enough on their plates without worrying about whether and when they should take an additional dose of COVID-19 vaccine and a flu shot.

But with larger holiday gatherings expected this year and flu season ramping up, experts warn of a surge of both COVID-19 and flu cases. That’s unwelcome news for the 3% of U.S. adults—some 7 million people, according to the Centers for Disease Control and Prevention—whose immune systems are moderately to severely compromised. Immunocompromised patients are especially vulnerable to COVID-19 and the flu because they often take medications that suppress their immune systems, making them less able to mount an effective response to infections.

The prescription, Cedars-Sinai experts say: Roll up your sleeves and get the shots.

“Immunocompromised patients absolutely should get a flu shot as well as an additional COVID-19 vaccine dose,” said neuroimmunologist Marwa Kaisey, MD, assistant professor of Neurology at Cedars-Sinai. “Otherwise, they are more likely to have worse outcomes if they get COVID-19 because they may not have built the same level of immunity from two doses of vaccine as those with healthy immune systems.”

The CDC recommends that immunocompromised people receive a third dose of Pfizer or Moderna vaccine at least one month after the second dose of the two-dose series. CDC experts also say it’s fine to mix or match the vaccines.

This week, Cedars-Sinai health professionals expect to vaccinate the health system's 100,000th patient since the COVID-19 vaccines became available in late-2020. And as more coronavirus variants are discovered, infectious disease experts say getting vaccinated becomes even more important. 

‘Additional Doses’ Versus ‘Boosters’

While the phrase “additional dose” sometimes is used interchangeably with “booster” in reference to COVID-19 vaccines, technically, their purposes are different, Kaisey explained. The “additional” shot may improve immunocompromised patients’ response to their initial two-dose series, bringing it closer to the protection level two doses provide those whose immune systems are not compromised.

A “booster,” on the other hand, is given to those who completed their two-dose vaccine series and protection against the virus is naturally wearing off over time, Kaisey said. They are advised to get the booster shot six months after their second vaccine dose of Pfizer or Moderna. Those who received the Johnson & Johnson vaccine may get a booster at least two months after receiving the one-shot vaccine. The Food and Drug Administration recently authorized booster shots of both the Pfizer-BioNTech and Moderna vaccines for everyone 18 and older.

Kaisey emphasized that the timing of additional shots—to get the most out of the vaccine—for immunocompromised patients depends on their specific conditions.

“Timing decisions should be based on when patients take their immune-suppressing medications,” Kaisey said. “They should consult with their doctor to determine that.”

Are You Immunocompromised?

Organ transplant recipients as well as patients with cancer or autoimmune disorders—including multiple sclerosis, rheumatoid arthritis, psoriasis, lupus, and advanced or untreated HIV infection—typically are immunocompromised.

Cancer treatments, such as chemotherapy, immunotherapy and radiation therapy, commonly suppress patients’ immune systems, said kidney cancer specialist Robert A. Figlin, MD, deputy director of Cedars-Sinai Cancer. Patients who have received a CAR-T cell or stem cell transplant for blood cancers within the last two years or are currently taking medicine to suppress their immune systems also risk a weakened response to vaccines.

Therefore, “It is critical that cancer patients with compromised immune systems receive additional vaccine doses,” added Figlin, the Steven Spielberg Family Chair in Hematology-Oncology and professor of Medicine and Biomedical Sciences. “Undervaccinated cancer patients often suffer worse COVID-19 and flu symptoms than those with strong immune systems.”

The immune response for vaccinated organ transplant patients is even more severely affected. Medications that prevent rejection of transplanted organs, such as a kidney, liver or lung, often block the production of protective COVID-19 antibodies.

“After two vaccinations, only about 20%-30% of our transplant patients are positive for COVID-19 antibodies,” said Stanley Jordan, MD, director of the Cedars-Sinai Nephrology and Transplant Immunology programs.

“This has raised a lot of concern about whether transplant patients should continue to socially distance, wear masks and surround themselves with a ‘wall of immunity’—meaning that they have contact only with vaccinated people,” Jordan said. “It’s created terrible angst among our patients, who ask, ‘I got vaccinated, what do I do now?’”

Jordan’s answer: “The third vaccine is very, very important for transplant patients,” he said. “A couple of excellent studies have found that patients got about a 60% immune response to the additional dose. We recommend that all of our patients get it. Those who received an additional dose of vaccine produced protective antibodies and longer-shielding T-cells.”

Read more about COVID-19 vaccines on the Cedars-Sinai Blog: Overcoming Vaccine Hesitancy Hurdles