Investigators recently reported that only 17% of solid organ transplant (SOT) recipients mount an antibody response to the first dose of the SARS-CoV-2 messenger RNA (mRNA) vaccines produced by Moderna and Pfizer-BioNTech. Now, in an updated analysis published in JAMA, the same research team has found low antibody response after the second dose, especially among patients receiving anti-metabolite maintenance immunosuppression.
Of 658 participants, 301 (46%) had no antibody response after dose 1 or dose 2, including 168 kidney transplant recipients, Brian J. Boyarsky, MD, PhD, of Johns Hopkins University School of Medicine in Baltimore, Maryland, and colleagues reported. Another 259 patients (39%), including 118 kidney transplant recipients, had no antibody response after dose 1 but responded to dose 2. Only 98 patients (15%), including 36 kidney transplant recipients, had an antibody response after both dose 1 and dose 2.
An antibody response was detectable at a median 21 days after the first dose and a median 29 days after the second dose. The investigators employed 2 immunoassays: the Roche Elecsys anti–SARS-CoV-2 S enzyme immunoassayassay, which measures total antibodies to the receptor-binding domain of the SARS-CoV-2 spike protein (threshold at least 0.8 U/mL), and EUROIMMUN, which tests for immunoglobulin G to the S1 domain of SARS-CoV-2 spike protein (threshold at least 1.1 arbitrary units). Among the 259 patients with no antibody response after first dose, antibody response after the second dose was 34.7 U/mL using the Roche immunoassay and 5.05 arbitrary units using the EUROIMMUN immunoassay. In the 98 patients with an antibody response after the first dose, the antibody response after the second dose was more than 250 U/mL using the Roche assay and 9.23 arbitrary units using the EUROIMMUN assay.
Among 473 SOT recipients receiving antimetabolites, 268 (57%) had no antibody response after dose 1 or dose 2, 167 (35%) had no antibody response after dose 1 but had a subsequent antibody response after dose 2, and 38 (8%) had antibody response after dose 1 and dose 2. Among 185 SOT recipients who did not receive antimetabolites, only 33 (18%) had no antibody response after dose 1 or dose 2, 92 (50%) had no antibody response after dose 1 but did so after dose 2, and 60 (32%) had antibody response after dose 1 and dose 2.
“Although this study demonstrates an improvement in antispike antibody responses in transplant recipients after dose 2 compared with dose 1, these data suggest that a substantial proportion of transplant recipients likely remain at risk for COVID-19 after 2 doses of mRNA vaccine,” Dr Boyarsky’s team stated. “Future studies should address interventions to improve vaccine responses in this population, including additional booster doses or immunosuppression modulation.”
In an online presentation mentioning this study, Liise-anne Pirofski, MD, chief of infectious diseases at Albert Einstein College of Medicine – Montefiore Medical Center in the Bronx, New York, emphasized that for SOT recipients COVID-19 prevention is crucial.
Disclosure: Some [or one] study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Boyarsky BJ, Werbel WA, Avery RK, et al. Antibody response to 2-dose SARS-CoV-2 mRNA vaccine series in solid organ transplant recipients. JAMA. Published online May 5, 2021. doi:10.1001/jama.2021.7489