A third dose of Pfizer COVID-19 vaccine could provide increased protection for cancer patients undergoing active treatment, revealed a new study.

A week following the administration of a third vaccine dose, neutralizing antibody responses were shown to improve in 80% of solid tumor patients who were undergoing chemotherapy. The adverse events were mild, reported researchers in Nature Medicine.

The study assessed immune responses following the two-dose Pfizer COVID-19 vaccine in 53 patients with solid tumors on active immunosuppressive cancer therapy, and compared them with 50 healthy controls. A phase I trial was then conducted of a third vaccine dose in the cancer cohort based on the two-dose results. Following the second vaccine dose, all healthy controls were found to have virus-neutralizing antibodies, with a median titer of 540, compared to 80% of the cancer cohort, with a median titer of 60. Of the 53 cancer patients, 20 participated in the phase I interventional trial. Following the third dose, neutralizing antibody levels were found to improve in 16 of the 20 patients, with titers of 180 or higher in 15 of the patients who experienced improvement… (Medpage Today)