Vaccination issues, evaluation of donors
Whether or not immunosuppression regimens should be adjusted prior to vaccination is a controversial question, but is “an absolutely valid one” and is currently being studied in at least one National Institutes of Health–funded trial involving solid organ transplant recipients, said Dr. Wolfe.
“Some have jumped to the conclusion [based on some earlier data] that they should reduce immunosuppression regimens for everyone at the time of vaccination ... but I don’t know the answer yet,” he said. “Balancing staying rejection free with potentially gaining more immune response is complicated ... and it may depend on where the pandemic is going in your area and other factors.”
Reductions aside, Dr. Wolfe tells lung transplant recipients that, based on his approximation of a number of different studies in solid organ transplant recipients, approximately 40%-50% of patients who are immunized with two doses of the COVID-19 mRNA vaccines will develop meaningful antibody levels – and that this rises to 50%-60% after a third dose.
It is difficult to glean from available studies the level of vaccine response for lung transplant recipients specifically. But given that their level of maintenance immunosuppression is higher than for recipients of other donor organs, “as a broad sweep, lung transplant recipients tend to be lower in the pecking order of response,” he said.
Still, “there’s a lot to gain,” he said, pointing to a recent study from the Morbidity and Mortality Weekly Report (2021 Nov 5. doi: 10.15585/mmwr.mm7044e3) showing that effectiveness of mRNA vaccination against COVID-19–associated hospitalization was 77% among immunocompromised adults (compared with 90% in immunocompetent adults).
“This is good vindication to keep vaccinating,” he said, “and perhaps speaks to how difficult it is to assess the vaccine response [through measurement of antibody only].”
Neither Duke University’s transplant program, which performed 100-120 lung transplants a year pre-COVID, nor the programs at UT Southwestern or the Mayo Clinic in Jacksonville require that solid organ transplant candidates be vaccinated against SARS-CoV-2 in order to receive transplants, as some other transplant programs have done. (When asked about the issue, Dr. Banga and Dr. Narula each said that they have had no or little trouble convincing patients awaiting lung transplants of the need for COVID-19 vaccination.)
In an August statement, the American Society of Transplantation recommended vaccination for all solid organ transplant recipients, preferably prior to transplantation, and said that it “support[s] the development of institutional policies regarding pretransplant vaccination.”
The Society is not tracking centers’ vaccination policies. But Kaiser Health News reported in October that a growing number of transplant programs, such as UCHealth in Denver and UW Medicine in Seattle, have decided to either bar patients who refuse to be vaccinated from receiving transplants or give them lower priority on waitlists.
Potential lung donors, meanwhile, must be evaluated with lower respiratory COVID-19 testing, with results available prior to transplantation, according to policy developed by the Organ Procurement and Transplantation Network and effective in May 2021. The policy followed three published cases of donor-derived COVID-19 in lung transplant recipients, said Dr. Wolfe, who wrote about use of COVID-positive donors in an editorial published in October.
In each case, the donor had a negative COVID-19 nasopharyngeal swab at the time of organ procurement but was later found to have the virus on bronchoalveolar lavage, he said.
(The use of other organs from COVID-positive donors is appearing thus far to be safe, Dr. Wolfe noted. In the editorial, he references 13 cases of solid organ transplantation from SARS-CoV-2–infected donors into noninfected recipients; none of the 13 transplant recipients developed COVID-19).
Some questions remain, such as how many lower respiratory tests should be run, and how donors should be evaluated in cases of discordant results. Dr. Banga shared the case of a donor with one positive lower respiratory test result followed by two negative results. After internal debate, and consideration of potential false positives and other issues, the team at UT Southwestern decided to decline the donor, Dr. Banga said.
Other programs are likely making similar, appropriately cautious decisions, said Dr. Wolfe. “There’s no way in real-time donor evaluation to know whether the positive test is active virus that could infect the recipient and replicate ... or whether it’s [picking up] inactive or dead fragments of virus that was there several weeks ago. Our tests don’t differentiate that.”
Transplants in COVID-19 patients
Decision-making about lung transplant candidacy among patients with COVID-19 acute respiratory distress syndrome is complex and in need of a new paradigm.
“Some of these patients have the potential to recover, and they’re going to recover way later than what we’re used to,” said Dr. Banga. “We can’t extrapolate for COVID ARDS what we’ve learned for any other virus-related ARDS.”
Dr. Narula also has recently seen at least one COVID-19 patient on ECMO and under evaluation for transplantation recover. “We do not want to transplant too early,” he said, noting that there is consensus that lung transplant should be pursued only when the damage is deemed irreversible clinically and radiologically in the best judgment of the team. Still, “for many of these patients the only exit route will be lung transplants. For the next 12-24 months, a significant proportion of our lung transplant patients will have had post-COVID–related lung damage.”
As of October 2021, 233 lung transplants had been performed in the United States in recipients whose primary diagnosis was reported as COVID related, said Anne Paschke, media relations specialist with the United Network for Organ Sharing.
Dr. Banga, Dr. Wolfe, and Dr. Narula reported that they have no relevant disclosures.