Predictors of poor seroconversion and adverse events to SARS-CoV-2 mRNA BNT162b2 vaccine in cancer patients on active treatment. Role of the Research Nurse.

BACKGROUND Vaccines have shown 95% protection from COVID-19 disease in healthy populations. Initial findings in cancer patients suggest a lower seroconversion and greater toxicity possibly related to myelo-immunosuppressive therapies. AIM We conducted a prospective study to assess factors predicting poor seroconversion and adverse events following immunization (AEFI) to the BNT162b2 vaccine in cancer patients on active treatment. METHODS Blood samples were collected by the research nurse at first dose (visit 1), second dose (visit 2), after 42 days (visit 3) and after 6 months (visit 4). At visit 1, 3 and 4 participants received: Hospital Anxiety and Depression Scale (HADS) and Distress Thermometer. Patients who ended treatment >6 months on active surveillance served as controls. RESULTS Between March and July 2021, 320 subjects were recruited and 291 were assessable. The lack of seroconversion at 21 days from the second dose was 1.6% (95% CI, 0.4-8.7) on active surveillance, 13.9% (8.2-21.6) on chemotherapy, 11.4% (5.1-21.3) on hormone therapy, 21.7% (7.5-43.7) on targeted therapy and 4.8% (0.12-23.8) on immunotherapy. Compared to controls, the risk of no IgG response was greater for chemotherapy (P=0.033), targeted therapy (0.005) and hormonotherapy (P=0.051). Lymphocyte count less than 1x109/L, older age and advanced stage also significantly predicted poor seroconversion. Overall, 43 patients (14.8%) complained of AEFI, mostly of mild grade. Risk of AEFI was greater in females (P=0.001) and younger patients (P=0.009). CONCLUSIONS A third booster dose and long-term serological testing is required in subjects who have not responded to the vaccine. NURSING IMPLICATIONS nurses must take responsibility for promoting and protecting the health of cancer patients.