FRIDAY, Aug. 20, 2021 (HealthDay News) — The seropositivity rate among patients with cancer remains high four months after the second dose of the COVID-19 vaccine, according to a research letter published online Aug. 11 in JAMA Oncology.

Noa Eliakim-Raz, M.D., from the Rabin Medical Center in Petah Tikva, Israel, and colleagues assessed the antispike (anti-S) immunoglobulin (Ig)G antibody response to the messenger RNA vaccine (BioNTech-Pfizer) in 95 patients with cancer versus 66 controls approximately four months after the second vaccine dose.

The researchers found that after a median of 123 days from the second vaccination, 87 percent of patients and 100 percent of the controls were seropositive for anti-S IgG antibodies. In patients with cancer, the median titer levels were significantly lower than those in the control group (417 versus 1,220 arbitrary units per milliliter). Median IgG titers varied 3.6-fold by tumor type and 8.8-fold by anticancer treatment type, with the lowest titers observed with immunotherapy plus chemotherapy and biological therapy.

“Long-term cellular memory could call into question the need for a third BNT162b2 booster dose,” the authors write.

One author disclosed financial ties to the pharmaceutical industry.

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