Benotmane I, Gautier G, Perrin P, et al. - Kidney transplant recipients who did not respond to 2 doses and received a third dose (100 μg) of the mRNA-1273 (Moderna) vaccine were investigated for the development of antibody responses.

• Researchers identified 159 kidney transplant recipients who exhibited SARS-CoV-2 antispike IgG levels less than 50 arbitrary units (AU) per milliliter after 1 month of the second dose.

• No antibody response was detected in 95 patients (59.7%) after 2 doses (titers < 6.8 AU/mL), and a response below the positivity limit was observed in 64 patients (40.3%) (titers, 6.8-49.9 AU/mL).

• A third dose of mRNA-1273 vaccine was injected after a median of 51 days (IQR, 48-59 days) following the second dose.

• 49% of kidney transplant recipients who did not respond after 2 doses showed a serologic response after the third dose.

• In this large group of kidney transplant recipients, the findings are in accordance with other studies of solid organ transplant recipients.

• However, anti–SARS-CoV-2 antibodies did not develop after the third dose in 51% of the patients, especially in those receiving triple immunosuppression.

• Some vaccinated transplant recipients showed the occurrence of severe COVID-19 suggesting the possible lack of immunity.