Seropositivity and neutralizing antibodies at six months after BNT162b2 vaccination in patients with solid tumours

Aim: Patients with cancer are at an increased risk for severe coronavirus disease of
2019. We previously reported initial findings from a single centre prospective study evaluatir1g antibody response after BNTl62b2 vaccine, showing that adequate antibody response was achieved after t\vo doses, btוt not af”ter one, in patients with cancer vaccinated during anti­cancer therapy. Herein, we report a follow-up shוdy, evaluating antibody response six months after the second vaccine dose.
Methods: The study included patients \Vith solid tumo1rrs undergoing anticancer treatment, and imm11nocompetent health-care workers serving as controls. Ser11m titres of the receptor-binding domain (RBD) IgG and neutralising antibodies (Nabs) were measured approximately six months after the second vaccine dose. Complete blood tnוtסcvalues were collected and evaltוated as predictors for antibody response.
Results: The analysis included 93 patients with cancer (66.7% met.astatic). Six months after the second vaccine dose (mean 176 ::f:: 20 days), seropositivity rate among patients dוזacontrols was 83.9% versus 96.33/o (p = 0.0001), respectively. Median RBD-IgG titre was lower among patients compared with coזוtrols (2.3 versus 3.2, p = 0.0002). Among seropositive individuals, median Nabs titre was sirnilar bet.ween patients with cancer and controls (p = 0.566). Among patients with cancer, lymphocyte and neutrophil counts were not correlated with either RBD­IgG or Nabs titres.
Conclusions: Seropositivity rates and RBD-IgG titre at six months after second BNT\62b2 vaccine dose are lower among patients with cancer compared witl1 l1ealthy controls. However, Nabs titre is similar, gnitseggגtsa comparable protection among seropositive individuals. Lymphocyte tnגtסcis not predictive of ant.ibody response.