A popular question among us. This link I believe has two studies from 2021:
This study may already be posted here, sorry if it's redundant.
mpn-hub.com/medical-informa...
In the 1st study, with n=62:
<<22.6% of patients did not have a detectable anti-spike level (< 0.4 U/mL)>>
Prior infection may help, including for MF, see "high titer" below. Anti-nucleocapside antibodies usually or always result from infection rather than vax :
<<6.5% showed positive anti-nucleocapside antibodies, with three patients reporting a previous SARS-CoV-2 infection.
-Two of the four patients (with anti-nucleo) had myelofibrosis (MF), three were vaccinated with Pfizer-BioNTech and one with Moderna vaccine.
-All seroconversion for anti-spike occurred with a high titer.>>
The group had a large cohort of MF patients, which likely drove much of the low average response:
<<This study demonstrated that the rate of seroconversion to mRNA SARS-CoV-2 vaccines was lower (77.4%) in patients with MPN compared to healthy adults and patients, with patients with MF showing the worst outcomes (< 60%) >>
The negative immune effect of Rux is known, but here they say the reason for that is not known:
<<The median anti-spike titers were adversely affected by treatment with ruxolitinib in responders; however, the cause was not known.>>
But as we know, the booster can help:
With the booster << there was a 200% increase in the spike protein antibody level.>>
-----------
The 2nd study was retrospective with n=74:
In ET, INF provides improved response vs HU or aspirin only, but HU is not bad vs aspirin:
<<In the ET cohort, spike protein antibody levels were higher (mean 4,151.15 AU/mL) in patients treated with pegylated interferon compared to patients treated with hydroxyurea (mean 2,368.62 AU/mL) or aspirin only (2,447.52 AU/mL).>>
In PV, the different therapies had no effect. This stands out and invites more questions re INF. But at least for HU it's consistent that HU is not detrimental to vax response for either ET, PV:
<<There was no difference in spike protein antibody levels between patient with PV receiving or not receiving cytoreductive therapy.>>
In MF Rux reduced vax reponse by 10X. They say a 10x reduction was not signif, something missing since that's quantitatively not true. Maybe the idea is either level is protective, which is familiar:
<<Lower levels of spike protein antibody were observed in the MF cohort when comparing patients on ruxolitinib (mean 603.1 AU/mL) vs those under observation (mean 6,353.29 AU/mL), but the difference was not statistically significant. >>
Rux has a negative effect:
<<Only three patients, one with CML on ponatinib, one with PV on ruxolitinib, and one with MPN-BP on ruxolitinib did not have measurable antibody response to vaccination.>>
On the Voice there have been some members with PV and no Rux with less than 0.4 antibodies I recall. So this study is correct that <<Further research with a larger cohort and extended follow-up period is therefore warranted>> But the pattern for Rux vs vax is consistent.