Immunogenicity, Safety, and Breakthrough Severe Acute Respiratory Syndrome Coronavirus 2 Infections After Coronavirus Disease 2019 Vaccination in Organ Transplant Recipients: A Prospective Multicenter Canadian Study

• Published in: Open forum infectious diseases Vol. 10; no. 5; p. ofad200
• Main Authors: Kabbani, Dima, Yotis, Demitra M, Ferreira, Victor H, Shalhoub, Sarah, Belga, Sara, Tyagi, Varalika, Ierullo, Matthew, Kulasingam, Vathany, Hébert, Marie-Josée, West, Lori, Delisle, Jean-Sébastien, Racine, Normand, De Serres, Sacha A, Cardinal, Héloïse, Dieudé, Mélanie, Humar, Atul, Kumar, Deepali
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.05.2023
• Subjects: Major; vaccines; SARS-CoV-2; solid organ transplant
• ISSN: 2328-8957; 2328-8957
• DOI: 10.1093/ofid/ofad200

Abstract Background Solid organ transplant (SOT) recipients are at risk for severe coronavirus disease 2019 (COVID-19), despite vaccination. Our study aimed to elucidate COVID-19 vaccine immunogenicity and evaluate adverse events such as hospitalization, rejection, and breakthrough infection in a SOT cohort. Methods We performed a prospective, observational study on 539 adult SOT recipients (age ≥18 years old) recruited from 7 Canadian transplant centers. Demographics including transplant characteristics, vaccine types, and immunosuppression and events such as hospitalization, infection, and rejection were recorded. Follow ups occurred every 4–6 weeks postvaccination and at 6 and 12 months from first dose. Serum was processed from whole blood to measure anti-receptor binding domain (RBD) antibodies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein to assess immunogenicity. Results The COVID-19 vaccines were found to be safe in SOT recipients with low rates of rejection requiring therapy (0.7%). Immunogenicity improved after the third vaccine dose, yet 21% developed no anti-RBD response. Factors such as older age, lung transplantation, chronic kidney disease, and shorter duration from transplant were associated with decreased immunogenicity. Patients with at least 3 doses were protected from hospitalization when experiencing breakthrough infections. Significantly increased anti-RBD levels were observed in patients who received 3 doses and had breakthrough infection. Conclusions Three or four doses of COVID-19 vaccines were safe, increased immunogenicity, and protected against severe disease requiring hospitalization. Infection paired with multiple vaccinations significantly increased anti-RBD response. However, SOT populations should continue to practice infection prevention measures, and they should be prioritized for SARS-CoV-2 pre-exposure prophylactics and early therapeutics.