Vaccination Status of Patients with Hematologic Malignancies Not Correlated with Severity of COVID-19 Infection


Although vaccination status and the severity of COVID-19 infection were not correlated, the timing of vaccine administration influenced whether patients had severe COVID-19 infection.

COVID-19 booster vaccines were introduced to improve the efficacy of vaccinations; however, the success varied across patients with hematologic malignancies. Further, the Omicron variant puts individuals at a higher risk for contracting COVID-19 because of its higher infection rate. A study published in Cancer Medicine evaluated the outcomes of patients with hematologic malignancies during the COVID-19 Omicron outbreak, and how the availability of vaccine boosters and antiviral treatments would impact the patients’ outcomes.

Health care professional administering a vaccine

Image credit: Zoran Zeremski |

This retrospective study included patients 18 years of age and older with hematologic malignancies (e.g., lymphoma, plasma cell neoplasms, etc.) during the Omicron outbreak, with data collection starting January 2022. They enrolled 116 patients with hematologic malignancies who were recruited from 2 medical centers and had to have a COVID-19 diagnosis confirmed by a real-time polymerase chain reaction (PCR) test or an institutional supervised rapid antigen test. Further, the majority of enrolled patients (n = 106; 91%) were vaccinated with the BNT162b2 mRNA vaccine, with 2, 3, and 4 doses in 12%, 44%, and 33% of patients, respectively.

Hematologic diagnoses included both lymphoma (non-Hodgkin and Hodgkin lymphoma; n = 33, 28%), chronic lymphocytic leukemia (CLL; n = 22, 19%), plasma cell neoplasms (n = 24, 21%), and myeloid neoplasms (n = 37, 32%). Approximately 80% of patients reported 1 or more comorbidities, the most common being hypertension (49%), cardiovascular disease (19%), and diabetes mellitus (16%). At the time of their COVID-19 diagnoses, 13% of patients were treatment-naïve, 61% were on active hematologic treatment, and 30% were previously treated for their hematologic diseases.

In addition, 78% of patients contracted COVID-19 between January and February 2022, and the remaining 22% contracted COVID-19 between March and April 2022. Further, severe COVID-19 cases were reported only during the first period, with 2 patients being hospitalized due to their COVID-19 infection. Severe COVID-19 infection was commonly associated with older age (>65 years of age), more than 1 comorbidity, and cardiovascular disease. Patients with CLL had a higher risk of developing severe COVID-19, whereas patients with myeloid neoplasms had the lowest risk. Approximately 26% of patients who were receiving active treatment for their hematologic malignancies had to pause treatment at the time of their COVID-19 infection, with the median time off being 10 days (range: 7 to 14 days).

There were no recorded associations between severe COVID-19 infection and vaccination status (vaccinated compared to unvaccinated) or the number of given doses (up to 2 vs 3 and 4 doses); however, patients who had received a vaccine dose between 7 and 90 days prior to COVID-19 infection were significantly less likely to develop severe COVID-19 infection. Further, antiviral COVID-19 therapies were given to approximately 44% of patients. Administration occurred within 5 days of infection onset in high-risk patients, and treatments included nirmatrelvir and ritonavir (n = 35; 69%), molnupiravir (n = 13; 25%), and short-course remdesivir (n = 3, 6%).

The investigators note that active hematologic treatment or specific treatment groups were not correlated with COVID-19 severity. In addition, no association was seen between severe COVID-19 infection and exposure to anti-CD20 antibodies, and according to the study authors, this finding is similar to prior research conducted during the Omicron outbreak. In addition, the potential reason for a lack of association between anti-CD20 therapy and COVID-19 infection during the Omicron outbreak could be a sustained response from vaccine administration prior to the initiation of therapy combined with preserved cellular response.

A limitation of the study is the small sample size, as it could have affected the investigators’ ability to detect more significant findings. Further, the authors note that the severity of hematologic outcomes, although noted prior to COVID-19 infection, could be an additional adverse effect of COVID-19 infection. The authors note that a 3-month period of increased vaccine efficacy can assist when determining the ideal timing for re-vaccination in high-risk populations.


Gutwein, O, Herzog K, Apel, A, et al. Timing of BNT162b2 vaccine prior to COVID-19 infection, influence disease severity in patients with hematologic malignancies: Results from a cohort study. Cancer Med. 2023; 00: 1-8. doi:10.1002/cam4.6397

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