Lower response to BNT162b2 vaccine in patients with myelofibrosis compared to polycythemia vera and essential thrombocythemia

In a population of 42 Philadelphia negative myeloproliferative neoplasm patients, all on systemic active treatment, the likelihood of responding to anti-SARS-CoV-2 BNT162b2 vaccine at 2 weeks after the second dose was significantly lower in the ten patients with myelofibrosis compared to the 32 with essential thrombocythemia (n=17) and polycythemia vera (n=15) grouped together, both in terms of neutralizing anti-SARS-CoV-2 IgG titers and seroprotection rates (32.47 AU/mL vs 217.97 AU/mL, p=0.003 and 60% vs 93.8%, p=0.021, respectively). Ruxolitinib, which was the ongoing treatment in five patients with myelofibrosis and three with polycythemia vera, may be implicated in reducing vaccine immunogenicity (p=0.076), though large prospective study is needed to address this issue.

Automated summary

Among 42 Philadelphia negative myeloproliferative neoplasm patients receiving systemic active treatment, those with myelofibrosis showed significantly lower response to the anti-SARS-CoV-2 BNT162b2 vaccine compared to patients with essential thrombocythemia and polycythemia vera in terms of IgG titers and seroprotection rates. The ongoing treatment with Ruxolitinib in some patients may be associated with reduced vaccine immunogenicity, but further large prospective studies are needed to confirm this finding.