Comparative immunogenicity of heterologous versus homologous 3rd SARS-CoV-2 vaccine doses in kidney transplant recipients
- Publié
- Serveur de preprints
- medRxiv
- DOI
- 10.1101/2022.01.25.22269778
Background
Solid organ transplant recipients have attenuated immune responses to SARS-CoV-2 vaccines. Emerging evidence suggests at least equivalent immunogenicity of heterologous compared with homologous vaccine regimens in the general population. In this study, we report on immune responses to 3 rd dose BNT162b2 vaccines in transplant recipients either primed with ChAdOx1 or BNT162b2.
Methods
700 kidney transplant recipients were prospectively screened for serological responses (median time of 33 (21-52) days) following 3 primary doses of a SARS-CoV2 vaccine. All vaccine doses were received post-transplant, and all 3 rd doses were BNT162b2. All participants had serological testing performed post-2 nd vaccination at a median time of 34 (IQR 26-46) days following the 2 nd inoculation, and at least once prior to their 1 st dose of vaccine.
Results
366/700 (52.3%) participants were primed with BNT162b2, whilst 334/700 (47.7) had received ChAdOx1. Overall, 139/700 (19.9%) participants had evidence of prior infection. Of 561 infection naïve participants, 263 (46.9%) had no detectable anti-S following 2-doses of vaccine (V2). 134 (23.9%) participants remained seronegative post 3 rd vaccine (V3); 54/291 (18.6%) and 79/270 (29.3%) of participants receiving BNT162b2 and ChAdOx1 respectively, p=0.0029. Median anti-S concentrations were significantly higher post-V3 in patients who had received BNT162b2 compared with ChAdOx1, at 612 (27-234) versus 122 (7.1-1111) BAU/ml respectively, p<0.0001.
Cellular responses were investigated in 30 infection naïve participants at a median time of 35 (24-46) days post-V3. Eighteen of 30 (60.0%) participants had undetectable T-cell responses. There were neither qualitative or quantitative differences in T-cell responses between those patients who received BNT162b2 or ChAdOx1 as their first 2-doses, with 10/16 (62.5%) and 8/14 (57.1%) respectively having undetectable T-cell responses, p=0.77.
Conclusion
A significant proportion of transplant recipients remain seronegative following 3 doses of SARS-CoV-2 vaccines, with anti-S concentrations lower in patients receiving heterologous versus homologous vaccinations.