HIGH SEROCONVERSION RATE and DELTA NEUTRALIZATION in PLWHIV VACCINATED with BNT162b2

ABSTRACT

Background: The emergence of SARS-CoV-2 variants is a major concern. As the Delta variant became dominant worldwide, obtaining specific data on the humoral and cellular responses after BNT162b2 vaccination against this variant of concern in PLWHIV is crucial. Methods: Multicenter cohort study of PLWHIV, with a CD4 cell count <500/mm3 and a viral load <50 copies/ml on stable antiretroviral therapy for at least 3 months, to explore humoral and cellular responses to BNT162b2 vaccination. IgG antibodies (Ab) to the Receptor Binding Domain (RBD) of the spike protein and their neutralization capacity, assessed by an ELISA (Genscript) and a virus neutralization test (VNT), against historical strain, Beta and Delta variants were performed before vaccination (day 0) and one month after a complete vaccination schedule (M1). Results: 97 patients were enrolled in the study (table 1. baseline characteristics). Among them, 85 patients received 2 shots (11 previous COVID-19 and 1 premature exit). The median time between the 2 shots was 28 [IQR 28-29] days. 90 patients could be evaluated at M1. The seroconversion rate in anti-RBD IgG was 97% CI95%[90%;100%] at M1. Median (IQR) anti-RBD Ab titer was 0.97 (0.97-5.3) BAU/ml at D0 and 1219 (602-1929) at M1. Neutralizing Ab capacity improved between D0 (15% CI95%[8%;23%]) and M1 (94% CI95%[87%;98%]) with the Genscript assay. Neutralizing Ab with the VNT were present at M1 for historical strain, Beta and Delta variants in 82%, 77% and 84% patients respectively. Planned subgroups analysis at M1 showed that seroconversion rate and median anti-RBD Ab titer were 91% and 852 BAU/ml in patients with CD4<250/mm3 (n=13) and 98% and 1270 BAU/ml in patients with CD4>250/mm3 (n=64) (difference of change between D0 and M1 between subgroups p=0.8224). 73% of patients with CD4<250/mm3 had neutralizing Ab and 97% of those with CD4>250/mm3 (p=0.0130). The neutralization capacity of beta variant was 50% in CD4<250/mm3 and 81% in CD4>250/mm3 (p=0.0292). No change in CD4+ or CD8+ T cells count was observed while a decrease of CD19+ B cells count was observed (208 ±124/mm3 at D0 vs 188 ±112/mm3 at M1, p<0.01). Tolerance was very good and no COVID-19 was reported until M1. Conclusion: These results show a high seroconversion rate with a Delta neutralization in PLWHIV patients after a complete BNT162b2 vaccination schedule. However, patients with CD4<250/mm3 had a decrease neutralizing Ab capacity mainly against Beta than Delta variant.