Humoral immunity of BBIBP-CorV (Sinopharm) in kidney transplant recipients: Is it time to revise vaccination strategies

Background The mortality of coronavirus disease 2019 (COVID-19) is high in transplant patients, and effective vaccination is aimed to reduce severe disease and mortality. Methods We conducted a cross-sectional study to evaluate humoral and cellular response to two 4-mu g doses of BBIBP-CorV vaccine in 100 kidney transplant recipients, using anti-spike IgG, total anti-receptor-binding domain, neutralizing antibody (Ab) level (enzyme-linked immunoassay), and interferon-gamma release assay (IGRA). Results Seroconversion was evaluated 85.84 +/- 30.72 days after the second dose. Note that, 58% of all and 43.05% of infection-naive participants have developed at least one of the tested antibodies. IGRA was positive in 30.7% of tested transplant recipients. Sixty percent of the participants had either humoral or cellular responses to COVID-19. Only age was independently linked to seropositivity of any degree after vaccination (p < .05). COVID-naive patients older than 60 years developed significantly less neutralizing Abs. (p = .011). Six patients developed mild COVID infection more than a month after the second dose of the vaccine (54.5 +/- 20.8 days). No vaccine-related adverse effects were reported, except self-limited mild to moderate fever and injection site pain. Conclusion BBIBP-CorV vaccine can be used safely in kidney transplant recipients, although impaired cellular and humoral immunity necessitate adjustments in vaccination strategies, like higher (8-mu g doses), fourth booster dose, or boost with different platform vaccine.