A May study published in the Journal of the American Medical Association found that 46 percent of transplant patients who got two doses of either the Moderna or Pfizer vaccine didn’t produce any COVID-19 antibodies, the key indicator of whether or not the vaccine was effective. The good news is that another 40 percent of the 658 transplant patients studied had no antibodies after their first vaccination but did develop antibodies after their second shot. However, that still leaves a large percentage of patients without any protection against COVID.ae0fcc31ae342fd3a1346ebb1f342fcb “This is really much more of a stark contrast than we had expected,” Dorry Segev, MD, a transplant surgeon at Johns Hopkins Hospital, told CBS News. “I’m hearing of transplant and other immunosuppressed people who got vaccinated and relaxed their safety behaviors and are now being admitted to hospitals and some are dying because they get COVID-19.” RELATED: 96 Percent of People Who Get the Pfizer Vaccine Have This In Common. Similarly, April research out of the Mayo Clinic, published in the American Journal of Transplantation, also raised concern that transplant patients seem to have a reduced immune response from the COVID-19 vaccine. The small study looked at seven organ transplant recipients diagnosed with COVID-19 at the Mayo Clinic in Florida after getting either of the mRNA vaccines, from Pfizer or Moderna. Two patients had been given one dose, and five were fully vaccinated. Five of the patients were hospitalized, three of whom required oxygen after they were discharged. Only one of the patients had antibodies against COVID. The research team therefore estimated that the infection rate in vaccinated solid organ transplant recipients is 10 times higher than the general population. “This study is eye-opening for the transplant community,” lead researcher Hani Wadei, MD, a Mayo Clinic Transplant Center nephrologist, said in a statement. “Our study suggests that transplant patients don’t have the same immune response as the general population. They got infected after getting vaccinated and lifting protective measures, thinking they were immune to the virus.” Wadei added: “Care should still be implemented in vaccinated solid organ transplant immunocompromised patients until we have better vaccine strategies. … All individuals, especially transplant patients, should continue to follow protective measures, such as social distancing, mask-wearing and regular hand hygiene.” RELATED: For more up-to-date information, sign up for our daily newsletter. Another study, published earlier this month in the journal Annals of the Rheumatic Diseases, looked at two groups of people who were vaccinated against COVID-19: 84 patients with autoimmune diseases (like rheumatoid arthritis, inflammatory bowel disease, psoriasis, and certain kinds of arthritis) and 182 healthy participants. In the latter group, all but one of the patients developed antibodies against COVID-19. In the former, as many as 1 in 10 people failed to develop any antibodies. In particular, the research showed that patients who take as methotrexate (sold as Rheumatrex, Trexall, Otrexup, Rasuvo) and rituximab (Rituxan) for their autoimmune diseases respond poorly to the vaccine, WebMD reports. That’s because these medications suppress the immune system so that the disorders, which cause your immune system to be overactive, are kept under control. Like Wadei, the Centers for Disease and Prevention (CDC) has cautioned people with compromised immune systems, including those who’ve gotten organ transplants, should continue wearing masks even if they’re fully vaccinated. “If you have a condition or are taking medications that weaken your immune system, you may NOT be fully protected even if you are fully vaccinated,” reads the CDC guidance, which was updated in mid-May. “Even after vaccination, you may need to continue taking all precautions.” CDC Director Rochelle Walensky, MD, expanded on that guidance during an appearance on NBC’s Meet the Press on May 16. “We know that—and there are emerging data to suggest—that if you don’t have a fully competent immune system from chemotherapy, from transplants, from other immune-modulating agents, that the vaccine may not have worked as well for you,” she said. “So, please, before you take off your mask, consult your physician.” RELATED: The CDC Just Changed This Controversial Guideline for Unvaccinated People.