Fourth Vaccine Dose May Up COVID-19 Immunity in Kidney Transplant Recipients

human kidney anatomy
Human kidney anatomy. 3d illustration
Fourth dose of mRNA vaccine increased antispike IgG titers in some kidney transplant recipients with weak serologic response after three doses

HealthDay News — A fourth dose of an mRNA-based anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine may increase antispike immunoglobulin (Ig)G titers in kidney transplant recipients, according to a research letter published online Jan. 11 in the Annals of Internal Medicine.

Sophie Caillard, M.D., Ph.D., from the University Hospitals of Strasbourg in France, and colleagues examined whether a fourth dose of an mRNA-based anti-SARS-CoV-2 vaccine would increase antispike IgG titers in 92 kidney transplant recipients (34 received BNT162b2; 58 received mRNA-1273) with antispike IgG titers <143 BAU/mL one month after the third dose.

The researchers found that no safety concerns were observed with the fourth dose. Median antispike IgG levels increased from 16.4 to 145 BAU/mL after a median of 29 days; 50 percent of patients reached the threshold of 143 BAU/mL. Patients who reached this threshold had a longer interval between transplant and fourth vaccine dose and less often received steroids. The percentage of patients with antispike IgG titers above 143 BAU/mL after the fourth dose was 48 and 52 percent for BNT162b2 and mRNA-1273, respectively; patients receiving mRNA-1273 had higher IgG titers (median 150 versus 122 BAU/mL). Only one patient was subsequently diagnosed with mild COVID-19; one month after the fourth dose, the patient’s antispike IgG level was 28 BAU/mL.

“We recognize that an increase in antispike IgG titers does not invariably provide protection from infection and disease, which is why we encourage longitudinal studies with a sufficient duration of follow-up to evaluate the risk for COVID-19 in patients like these after additional vaccine doses,” the authors write.

Two authors disclosed financial ties to the biopharmaceutical industry.

Abstract/Full Text