COVID-19 Vaccines May Not Provide Adequate Protection In Haematological Cancer Patients

Author: By Shreeya Nanda, Senior medwireNews Reporter 

medwireNews: A single-centre US study has found a low rate of seroconversion after two doses of the Pfizer–BioNTech or Moderna SARS-CoV-2 vaccines or a single dose of the Johnson & Johnson vaccine in patients with haematological cancers. 

Less than half (39%) of the 160 study participants achieved seroconversion, as indicated by a positive result on the qualitative SARS-CoV-2 Total Antibody Test, even after full vaccination, report the investigators in a research letter published in JAMA Oncology. 

The antibody response was even poorer among individuals who had previously been treated with B-cell-depleting monoclonal antibodies, with a seroconversion rate of 29% versus 60% for those who had not received such treatments, a significant difference. 

Three patients – all of whom had no detectable antibodies after vaccination – developed a breakthrough SARS-CoV-2 infection, with one proving fatal. 

The researchers caution that “[t]he qualitative test for anti–COVID-19 antibodies does not inform about T-cell–based immunity and has not been correlated with clinical outcomes related to potential COVID-19 infection.” 

Nonetheless, they believe these results “raise a concern that patients with hematologic cancers, particularly those receiving B-cell–depleting immunotherapy, may not gain adequate protection from vaccination, and as observed in our cohort, may still develop a potentially fatal infection.” 

To examine the effectiveness of COVID-19 vaccination “in patients with hematologic malignant disease who have an impaired humoral immunity from both treatment and disease”, the investigators from Rhode Island Hospital in Providence, USA, identified 160 patients who received two doses of the Pfizer–BioNTech or Moderna vaccines or one dose of the Johnson & Johnson vaccine at their institution in February–April 2021. 

Participants were aged a median of 72 years and just over half (54%) were men. The most common haematological cancer in the study population was aggressive B-cell lymphoma, in 36%, followed by indolent B-cell lymphoma, in 21%. Two-thirds of the patients had received B-cell-depleting therapies, most commonly rituximab. 

The majority (60%) received the Pfizer–BioNTech vaccine, with a respective 31% and 7% receiving the Moderna and Johnson & Johnson vaccines. 

Thomas Ollila and colleagues report that the seroconversion rate as assessed by the qualitative assay was significantly lower among patients with active disease than those in remission after treatment or undergoing watchful waiting without receipt of anticancer therapy, at 27% versus 49% and 67%, respectively. 

The rate was similarly significantly lower among participants who were vaccinated within 12 months of their last chemotherapy treatment than for those who completed treatment more than 12 months prior to vaccination, at 24% versus 69%. 

The findings were similar when quantitative immunoglobulin assays were used instead, say the study authors. 

Thomas Ollila et al therefore suggest that people with haematological cancers “may benefit from ongoing protective measures, including masks, social distancing, and screening.” 

And they conclude: “Consideration should be made to prioritizing vaccination for family members and caregivers to protect the patients themselves. With possible infection, we recommend testing regardless of vaccination status, and treatment with COVID-19–specific monoclonal antibody therapy.” 

Reference  

Ollila TA, Lu S, Masel R, et al. Antibody response to COVID-19 vaccination in adults with hematologic malignant disease. JAMA Oncol; Advance online publication 11 August 2021. doi: 10.1001/jamaoncol.2021.4381