As the Covid-19 pandemic continues, experts have become increasingly concerned with the efficacy of the available COVID-19 vaccines in immunocompromised patients. A team of researchers sought to evaluate responses to the mRNA vaccines in patients with BCR-ABL1-negative myeloproliferative neoplasms (MPNs). The findings were published in Blood Cancer Journal.

The researchers evaluated 62 patients with MPNs at a single center in Milan, Italy, who were vaccinated for COVID-19 between March and June 2021. Median age at vaccination was 71.9 years (range, 33.7 to 86.3). Of those patients, 26 had myelofibrosis (MF) and 36 had other MPNs. All but 5 were undergoing active treatment. Of those receiving treatment, 30 were receiving ruxolitinib. Other treatments included hydroxycarbamide (HU; 15), interferon alpha (4), anagrelide (3), givinostat (3), and other JAK inhibitors (2).

Compared with health adults of similar age groups, COVID-19 vaccine response was lower in patients both with MF diagnosis (57.7% vs 91.7%; P =.002) and receiving ruxolitinib therapy (66.7% vs 87.5%; P =.05). Among patients with MF, lower response was evident among both those not receiving ruxolitinib (66.7% vs 95.7%) and in those treated with ruxolitinib (52.9% vs 84.6%).

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In univariate analysis, the researchers found several factors were associated with lower anti-spike levels: MF diagnosis, older age, ruxolitinib therapy, and a short time (less than 3 years) from initiation of ongoing therapy to vaccination. But ultimately, only the MF diagnosis and ruxolitinib therapy were confirmed by multiple regression analysis.

These results demonstrate that rate of seroconversion to mRNA SARS-CoV-2 vaccines in patients with MPNs (77.4%) is lower compared with healthy people, and patients with MF have the worst response. Treatment with ruxolinitib also adversely affected median anti-spike titers among responders.

The researchers suggest that patients with MPNs, especially those with MF, should diligently follow protective measures against COVID-19, regardless of whether they are receiving ruxolitinib and even after being vaccinated.

The study was limited by its nature as a single center study.


Cattaneo D, Bucelli C, Cavallaro F, et al. Impact of diagnosis and treatment on response to COVID-19 vaccine in patients with BCR-ABL1-negative myeloproliferative neoplasms: a single-center experience. Blood Cancer J. 2021;11(11):185. doi:10.1038/s41408-021-00579-0