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HUMORAL AND CELLULAR IMMUNE RESPONSE AFTER MRNA BNT162B2 COVID-19 VACCINE AMONG IMMUNOCOMPROMISED ADOLESCENTS
Abstract
Background
Lower antibody response to the COVID-19 vaccine has been reported in immunocompromised adults. However, data on the humoral and cellular immune response among immunocompromised adolescents are scarce.
Aims
To evaluate the humoral and cellular immune response to the BNT162b2 vaccine in immunocompromised adolescents.
Methods
This prospective cohort study included immunocompromised adolescents aged 12 to 18 years. Two doses of BNT162b2 were administered 21 days apart. The humoral immune response was assessed by surrogate virus neutralization test (sVNT) against Delta variant before and 4 weeks after the second dose. In addition, the ELISpot was used to determine cellular immune response against the S protein. A threshold of > 95 spot-forming units (SFUs)/106 peripheral blood mononuclear cells (PBMCs) indicates detectable T-cell responses.
Results
Thirty-seven immunocompromised adolescents included 8 kidney transplants, 11 bone marrow transplants, 16 rheumatologic disorders, and 2 cancer patients with a median age of 15.6 years (IQR 14.2, 17.8), were enrolled. Among 37 patients, only 3 (8.1%) and 23 (62.2%) patients achieved sVNT > 80% inhibition after the first and the second dose, respectively. Additionally, 29 (76.3%) patients demonstrated T-cell responses with the median spike-specific T-cell response of 220 (IQR 100, 428) SFUs/106 PBMCs. However, there was no correlation between sVNT and the magnitude of T-cell responses (Spearman’s rho: 0.18; P=0.28).
Conclusions
Two-third of immunocompromised adolescents developed humoral immune response after 2 doses of BNT162b2, but discordance between sVNT and T-cell responses was observed. Therefore, assessing only the humoral response may underestimate the immunogenicity of the vaccine.