Abstract
The rising need for repeated booster vaccinations against SARS-CoV-2 infections raises the question of whether chronic immunosuppressive chemotherapies influence the efficacy of vaccination. Here, we present the case of a 70-year-old post-thymoma surgery patient who received Vepesid (etoposide, Xediton Pharmaceuticals Inc) chemotherapy for six months before vaccination with Comirnaty (Pfizer-BioNTech COVID-19 mRNA Vaccine). The first two vaccinations elicited only minimal increases of IgG antibodies specific against the receptor-binding domain (RBD) on the spike protein (S1), while the third vaccination was effective in providing high, slowly subsiding antibody titers over a 7-month period. The patient also developed a cellular immune response after the third vaccination. Also, measuring of anti-polyethylene glycol (PEG) IgM titers before and after vaccinations showed no immunogenicity for PEG. Later, a single dose of Sinopharm (China National Pharmaceutical Group) inactivated virus-type vaccine was administered, which also modestly increased the level of IgG. A symptomless COVID-19 infection, however, greatly increased the serum level of anti-RBD IgG, which later subsided. This case confirms that an effective immune response can be achieved with a series of COVID-19 vaccinations despite cytostatic treatment in an old thymus cancer surviving patient in the absence of adverse reactions.