Possible solutions for those with low antibody responses
Dr. Larsen said that those with ongoing low antibody responses might still have other immune responses, such as a T-cell response. Such patients also could consider changing their vaccine type, he said.
“At the more significant intervention level, there may be circumstances where one could change the immunosuppressive drugs in a controlled way that might allow a better response,” suggested Dr. Larsen. “That’s obviously going to be something that requires a lot more thought and careful study.”
Dr. Werbel said that other options might need to be considered for those having no response following a third dose. One possibility is trying a vaccine with an adjuvant, such as the Novavax version, which might be more widely available soon.
“If you’re given a third dose of a very immunogenic vaccine – something that should work – and you just have no antibody development, it seems relatively unlikely that doing the same thing again is going to help you from that perspective, and for all we know might expose you to more risk,” Dr. Werbel noted.
Participant details
None of the 30 patients were thought to have ever had COVID-19. On average, patients had received their transplant 4.5 years before their original vaccination. In 25 patients, maintenance immunosuppression included tacrolimus or cyclosporine along with mycophenolate. Corticosteroids were also used for 24 patients, sirolimus was used for one patient, and belatacept was used for another patient.
Fifty-seven percent of patients had received the Pfizer/BioNTech vaccine originally, and 43% the Moderna vaccine. Most of the patients were kidney recipients, with two heart, three liver, one lung, one pancreas and one kidney-pancreas.
Dr. Werbel, Dr. Wender, and Dr. Larsen reported no relevant disclosures.