COVID-19 Antibodies Are Similar for Those With Solid Tumors Compared With Those Without 6-Months After the Second Dose

Patients with cancer and those without cancer had similar serologic results 6-months after receiving their second BNT162b2 vaccine.

After 6 months, patients with solid tumors and who received the second dose of Pfizer’s BNT162b2 vaccine (Comiraty) retained similar levels of SARS-CoV-2 antibodies compared with the general population of patients without cancer, according to a study published by the American Association for Cancer Research.1

In total, 79% of patients (n = 122) who were receiving active treatment for cancer were compared with 84% (n = 114) of those in the control group. There was no significant difference found between groups when comparing age, sex, or disease stage. Among the cancer cohort, treatment with chemotherapy was associated with a seronegative serologic status vs other therapies (27% vs 10%; OR, 0.31; P = .02). Among the population of patients who were seronegative, 81% were actively undergoing chemotherapy. In the population of seropositive individuals, a female predominance was noted in the control cohort compared with the patient group (93% vs 75%; OR, 0.21; P = .004).

“In our study we saw that in all outcomes, including immunogenicity, infectivity rate throughout the 6-month period, and safety, patients with solid tumors depicted a similar trend as the general population,” Irit Ben-Aharon, MD, PhD, director of the Oncology Division at Rambam Healthcare Campus in Israel, said in a press release.2

A total of 154 patients who were undergoing active intravenous treatment for their disease were included in the study, as well as the 135 age-matched health care workers who acted as the control group. The majority of patients with cancer who enrolled on the study were men (55%; n = 84) and the median patient age was 66 years. In the control group, 56% of participants were men (n = 75) and the median age was 63 years.

Patients were tested 166±29 days after the second dose and 187 days from the first dose. In the patient group, 84% (n = 129) had metastatic disease. The most common cancer types among patients who enrolled on the study included gastrointestinal cancer (36%; n = 56), lung cancer (23%; n = 36), breast cancer (17%; n = 26), and genitourinary cancer (11%; n = 18). Most patients had metastatic disease (84%; n = 129). Active cancer therapies included chemotherapy (62%), biological agents (36%), or immunotherapy (30%), although some patients notably received more than 1 class of drug.

Between the 2 cohorts, no significant difference in median absolute serology titer was noted among seropositive individuals. Additionally, both cohorts demonstrated a drastic decline over time in serology titers over 6 months, however, it remained above threshold value. A total of 15% of seropositive patients became seronegative after 6 months, which was comparable with the control group. Patients who achieved seronegativity remained seronegative throughout the study.

Investigators reported 1 documented case of COVID-19 infection following the second dose of the vaccine in the patient cohort, which required hospitalization. Of note, there were no other reported cases of COVID-19 during this study.

Elevation of liver enzyme levels was documented in 10% of patients up to 6-weeks following the first dose. Additionally, 5% of patient had newly documented regional lymphadenopathy that was identified through CT or PET scans that were performed during routine cancer care.

In total, 6% (n = 9) of patients’ anticancer treatment was delayed for 2 weeks after vaccination; all patients within this population were receiving chemotherapy. Additional treatment delays were due to neutropenia (n = 7), mild thrombocytopenia (n =1), and neutropenia with herpes labials (n = 1). In all patients with neutropenia, there was a gradual decline before vaccination, or neutropenia was found in other cycles. All patients had treatment renewed within a week for all patients.


1. Waldhorn I, Holland R, Goshen-Lago T, et al. Six month efficacy and toxicity profile of BNT162b2 vaccine in cancer patients with solid tumors. Cancer Discov. Published online first, September 2, 2021. doi: 10.1158/2159-8290.CD-21-1072

2. Six-month efficacy of Pfizer/BioNTech COVID-19 vaccine in patients with solid tumors similar to general population. News Release. American Society for Cancer Research. September 2, 2021. Accessed September 2, 2021.