When compared with healthy individuals, patients with cancer have lower levels of anti-spike protein (anti-S) antibodies after COVID-19 vaccination, according to research published in JAMA Oncology.

Though some patients studied had increases in anti-S antibodies after a second vaccine dose, antibody levels remained low — a median of 0 U/mL — in patients with hematologic malignancies receiving B cell-targeting agents.

For this study, researchers retrospectively analyzed data from 595 patients with cancer and 58 health care workers (HCWs).

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The patient group was made up of 2 cohorts — the Vienna cohort (n=111) and the Meran cohort (n=484) — and included patients with solid tumors (n=382) and hematologic cancers (n=213).

Prior SARS-CoV-2 infection was verified in 4.5% of the Vienna cohort, 7.9% of the Meran cohort, and 3.4% of the HCWs. Anti-SARS-CoV-2 nucleocapsid antibodies were detected in 6.3%, 9.1%, and 5.2%, respectively.

Vaccination Details

All 484 patients in the Meran cohort were vaccinated against COVID-19, as were 24 patients in the Vienna cohort and 43 in the HCW cohort. All Meran patients received the Pfizer/BioNTech vaccine, as did 58.3% of the Vienna patients and 67.3% of the HCWs.

The AstraZeneca vaccine was given to 20.4% of HCWs and 16.7% of the Vienna cohort. Only patients in the Vienna cohort (25.0%) received the Moderna vaccine.

At last follow-up, 64.6% of HCWs had received 2 doses of a vaccine, and 18.8% had received 1 dose. All patients in the Meran cohort had received at least 1 dose, and 25.8% had received 2. In the Vienna cohort, 62.5% of patients were partially vaccinated, and 37.5% had received 2 doses.

Antibody Levels: Patients vs HCWs

A direct comparison of anti-S levels was only possible between HCWs and patients in the Vienna cohort because of the assays used.

After the first vaccination, the median anti-S level was 30.60 U/mL in the HCWs and 0 U/mL in the Vienna cohort (P <.001). After both doses, the median anti-S levels were 2500 U/mL and 117 U/mL, respectively (P <.001).

In the Vienna cohort, the difference in anti-S levels between partially and fully vaccinated patients was statistically significant (P =.01).

The Vienna cohort was too small for the researchers to compare antibody levels by cancer type, treatment type, or the vaccine used in fully immunized patients.

Antibody Levels by Cancer and Treatment Type

In the Meran cohort, the median anti-S level was 201.2 AU/mL after the first vaccine dose.

There were 125 patients with anti-S levels of less than 50 AU/mL who underwent antibody testing again after the second vaccine dose. Median anti-S levels increased in this group, from 1.7 AU/mL after the first dose to 50 AU/mL after the second (P <.001).

However, 49.6% of patients with impaired seroconversion after the first dose still had low anti-S levels after the second dose.

Patients with hematologic cancers had lower median anti-S levels compared with solid tumor patients — 139.3 AU/mL and 246.4 AU/mL, respectively (P =.01) — and the researchers attributed this to the use of B cell-targeting therapies.

After the second vaccination, the median anti-S level was 0 U/mL in patients receiving B cell-targeting agents, 172.8 U/mL in patients with hematologic malignancies not receiving B cell-targeting therapies, and 124.9 U/mL in patients with solid tumors.

Among patients with solid tumors, seroconversion differed according to ongoing antineoplastic treatment. However, this was only seen after the first vaccine dose, not after the second.

After 1 vaccination, the median anti-S level was 157.7 AU/mL in patients who received chemotherapy only, 118.7 AU/mL in those who received chemo-immunotherapy, and 634.3 AU/mL in patients receiving no antineoplastic treatment.

“The included patients represent a wide spectrum of solid tumors and blood cancer as well as antineoplastic treatments, providing real-life insights,” the researchers wrote. “However, dedicated trials that evaluate the effectiveness of SARS-CoV-2 vaccination in patients with cancer are needed to ensure optimal cancer care during the pandemic and beyond.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures. 


Mair MJ, Berger JM, Berghoff AS, et al. Humoral immune response in hematooncological patients and health care workers who received SARS-CoV-2 vaccinations. JAMA Oncol. Published online September 30, 2021. doi:10.1001/jamaoncol.2021.5437