The Humoral Response of Patients With Cancer to Breakthrough COVID-19 Infection or the Fourth BNT162b2 Vaccine Dose

Since January 2022 in Israel, high-risk populations with underlying health conditions were advised to receive a fourth dose of the BNT162b2 vaccine (Pfizer-BioNTech) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We monitored vaccine-induced immunity among oncology patients undergoing systemic anti-cancer therapy before and after the 4th-BNT162b2-dose. Three groups of patients were included in the study: those who received 3rd-BNT162b2-dose and had no breakthrough infection (control), those who received 3rd-BNT162b2-dose and had the breakthrough infection, and those who received the 4th-BNT162b2-dose and had no breakthrough infection. Anti-SARS-CoV-2 immunoglobulin-G (IgG) levels of the control group exhibited a rapid decrease over time, whereas IgG titers of patients with breakthrough-infections or patients vaccinated with the 4th-BNT162b2-dose were considerably elevated, consistent with the capacity of the second booster to induce anti-SARS-CoV-2 IgG levels. Additionally, oncology patients' humoral immune response was significantly greater after breakthrough-infection than in response to the 4th dose of BNT162b2. Since January 2022 in Israel, high-risk populations with underlying health conditions were advised to receive a fourth dose of the BNT162b2 vaccine against SARS-CoV-2. This article reports on vaccine-induced immunity among oncology patients undergoing systemic anti-cancer therapy before and after the 4th-BNT162b2-dose.

Automated summary

Since January 2022, high-risk populations in Israel have been advised to receive a fourth dose of the BNT162b2 vaccine for protection against SARS-CoV-2. This study monitored the vaccine-induced immunity among oncology patients undergoing anti-cancer therapy before and after the fourth dose of BNT162b2. The results showed that antibody levels were higher in patients who had breakthrough infections or received the fourth dose, compared to the control group.