Review of Immunization Status of Patients Switched to Ocrelizumab: A Tertiary Care Experience

Background: Ocrelizumab, a newly approved B-cell depleting therapy for relapsing-remitting and progressive MS, induces prolonged immunosuppression. On Ocrelizumab, no live vaccine can be given and inactive vaccines while safe may not induce substantial immunization effects. No specific recommendations to guide immunizations in this cohort exist.

Objectives: To review the vaccination status of patients with multiple sclerosis (MS) considered for escalation to Ocrelizumab and evolving standards of care at an academic MS Center.

Methods: Chart review of the vaccination status of the first cohort of patients started on Ocrelizumab since its approval in March 2017.

Results: During March-September 2017, 86 patients were treated with Ocrelizumab at our site: 52.3% were male, 47.6% female; mean age 45.9 years. Patients with protective titers to Hepatitis B antibody, 32.5% (n=28) on baseline screening, were deemed to have sufficient immunity. 65.1% (n=56) had nonreactive and 2.32% (n=2) indeterminate titers; of these patients 50% were subsequently vaccinated prior to Ocrelizumab. Of the 86 total patients, 6.97% were previously and 51.2% were subsequently vaccinated with pneumococcal conjugate 13 (Prevnar®) or 23(Pneumovax®) prior to Ocrelizumab dosing. 76 patients (88.3%) had baseline VZV status assessment; 2 patients demonstrated insufficient immunity and were subsequently vaccinated with live vaccine (Varivax®) prior to Ocrelizumab dosing. Ten patients (11.6%) reported prior varicella infection but titers were not checked. Patients already on a B-cell depleting therapy (rituximab), very active MS disease, patient refusal and evolving clinic standards were the main factors for deferring vaccinations. In those vaccinated, the interval between completion of immunizations and Ocrelizumab averaged 39.7 days (range 21-91days).

Conclusions: A significant number of MS patients transitioned to ocrelizumab were not vaccinated or had insufficient immunity for basic  vaccines on baseline screening. Given that these vaccines are safe and effective in preventing infections, it appears warranted that MS patients should be screened and educated on vaccinations, especially when more potent agents with prolonged immuno suppression, such as ocrelizumab and others, are considered. We have updated our clinic standards in that regard.