H. Zoster Subunit Vaccine Efficacy with JAK Inhibitor Therapy Save

JAK inhibitors are known to increase the risk of herpes zoster infections between between 3-5 fold.  Two recent reports suggest variable efficacy when JAK inhibitor (JAKi) treated patients are vaccinated with the recombinant herpes zoster subunit vaccine (RZV). 

One study in Sweden looked RZV responses in 82 rheumatoid arthritis (RA) patients compared to 51 healthy controls.  All patients received two doses of HZ/su (Shingrix). Both patients and controls significantly mounted a vaccine-specific antibody response (P < 0.0001), with 80.5% of RA patients and 98% of controls demonstrating a ≥4-fold increase in antibody levels.

However, post-vaccination antibody levels were lower in RA patients compared to controls [ratio 0.44 (95% CI 0.31, 0.63)] and were also significantly lower when methotrexate was added to JAKi therapy [ratio 0.43 (95% CI 0.24, 0.79)]. compared to JAKi monotherapy.  In this study one patient developed HZ and six patients (6.5%) had increased RA disease activity following vaccination.

Another study from Spain studied the immunogenicity and safety of RZV in IMID patients on JAKi therapy.  This included 14 with RA, 2 PsA, 2 SpA, and one SLE. They studied 49 patients, showing that humoral seroconversion (>fourfold increase in antibody concentration) was only achieved in 39% of patients. Nearly 45% had at least a 3-fold response; and 82% had at least a doubling of their antibody titers. These results were unrelated to activity (63% were in remission) or background DMARD use  (33%). There was only only one serious adverse effect of local swelling. These authors called for more studies of such patients, but recanted the importance of RZV immunization in immunosuppressed patients. 

The RZV vaccine is serologically immunogenic in most RA patients and should be considered in those being treated with JAKi.