The evidence for the efficacy of the COVID-19 vaccination in patients with compromised immunity is weak. These patients appear to have a weaker humoral reaction, based on the first findings. For a study, researchers assessed the efficacy of the mRNA BNT162b2 vaccination to that of matched controls in patients with hematological neoplasms. After two vaccination doses, data on patients with hematological neoplasms were retrieved and matched 1:1 with vaccinated controls. Patients undergoing therapy for hematological neoplasms, patients without treatment who were just followed, and patients getting specialized therapies were the subjects of subpopulation analyses. The study examined COVID-19 outcomes from days 7 to 43 following the second vaccination dose in the following areas: verified COVID-19 infection by polymerase chain reaction; symptomatic infection; hospitalizations; severe COVID-19 illness; and COVID-19–related mortality. A total of 32,516 patients with hematological neoplasms were found in a community of 4.7 million insured persons, 5,017 of them were getting treatment for an active illness. 

When compared to vaccinated matched controls, vaccinated patients with hematological neoplasms had an increased risk of documented infections (relative risk [RR] 1.60, 95% CI 1.12-2.37); symptomatic COVID-19 (RR 1.72, 95% CI 1.05-2.85); COVID-19–related hospitalizations (RR 3.13, 95% CI 1.68-7.08); severe COVID-19 (RR 2.27, 95% CI 1.18-5.19)  COVID-19–related death (RR 1.66, 95% CI 0.72-4.47). Patients taking hematological therapies were shown to be at greater risk when the study was restricted to them. 

The study found that vaccinated patients with hematological neoplasms, particularly those receiving treatment, were more likely to have COVID-19 results than vaccinated persons with a healthy immune system. Additional dosages, for example, should be investigated as a way to boost COVID-19 immunity in the patient population.