Improved immunogenicity following the third dose of BNT162b2 mRNA vaccine in heart transplant recipients

Abstract

OBJECTIVES The immunogenicity of two-dose severe acute respiratory syndrome coronavirus 2 vaccine is lower among heart transplant (HTx) recipients, compared with the general population. Our aim was to assess the immunogenicity of a third-dose vaccine in HTx recipients. METHODS This is a prospective cohort study of HTx recipients who received a third dose of the BNT162b2 vaccine. Immunogenicity was assessed by serum levels of anti-spike immunoglobulin G (S-IgG), taken at baseline and 14–28 days after the third dose. Titres above 50 U/ml were interpreted positive. RESULTS We Included 42 HTx recipients at a median age of 65 years [interquartile range (IQR) 58–70]. At baseline, the median of 27 days (IQR 13–42) before the third dose and the median titre of the whole group was 18 U/ml (IQR 4–130). Only 14 patients (33%) were S-IgG seropositive. After the third dose, the proportion of seropositive patients increased significantly to 57% (P = 0.05) and the median titre increased significantly to 633 U/ml (IQR 7–6104, P < 0.0001). Younger age at HTx (OR per 1-year decrease 1.07, P = 0.05), low tacrolimus serum level (OR per 1-unit decrease 2.28, P = 0.02), mammalian target of rapamycin use (OR 13.3, P = 0.003), lack of oral steroids use (OR 4.17, P = 0.04) and lack of calcineurin inhibitor use (71% of responders vs 100% non-responders received calcineurin inhibitors, P = 0.01) were predictors of seropositive result after the third dose. However, no significant association was detected following adjustment for baseline S-IgG titre. CONCLUSIONS Third-dose booster of BNT162b2 vaccine significantly increased immunogenicity among HTx recipients who previously received a two-dose vaccine.

Humoral and cellular immune response after severe acute respiratory syndrome coronavirus 2 messenger ribonucleic acid vaccination in heart transplant recipients: An observational study in France

“…Our findings are in line with two recent studies. They reported, 3 weeks after vaccination, that additional third and fourth boosters of BNT162b2 vaccine improved the magnitude of IgG anti-RBD SARS-CoV-2 antibody response in seropositive HT recipients and the proportion of IgG responsive patients increase to 57 and 80%, respectively, compared to the range achieved after the two primary doses (19,20,32). Moreover, in our study, a large proportion of patients, more than eighty percent, with a high antibody response had a positive T-cell response.…”

Measures to Increase Immunogenicity of SARS-CoV-2 Vaccines in Solid Organ Transplant Recipients: A Narrative Review

“…One study showed antibody positivity increased from 68% to 90% in HTRs, and 43% to 63% in LTRs, one month after the third dose of an mRNA vaccine, but only 59% of HTRs and 25% of LTRs had developed enough antibodies to neutralize the omicron variant [ 67 ]. More recent studies with HTRs showed a seroconversion rate increase from 30% to 34% after two doses of a vaccine (BNT162b2, mRNA1273, or AZD 1222), from 57% to 63% after the third vaccine dose [ 68 , 69 , 70 ], and up to 80.7% with the fourth dose [ 71 ].…”

“…In two studies including liver transplant recipients and one of HTRs, the rates of cellular response were increased by repeated vaccines [ 39 , 68 , 75 ]. However, a liver transplant study showed that only 37% of liver transplant recipients had positive IGRA results 29 days after the second vaccine with mRNA vaccine or AZD1222 [ 76 ].…”