The use of progressively more powerful disease-modifying therapies (DMTs) in multiple sclerosis (MS) has increased the risk of severe infection of vaccine-preventable diseases, as hepatitis B (HBV). Considering the low risk of vaccination and the potential complication of acute infection by HBV in patients undergoing immunomodulating therapies, vaccination is considered in seronegative patients.
We aimed to evaluate if immunosenescence and DMT-treatment influenced the seroconversion rate following HBV vaccination.
We selected all seronegative MS patients submitted to HBV vaccination in our institution between January 2016 - May 2020. In our center, an accelerated HBV vaccination regimen is administrated with a 3 dose protocol (Day 0, 7, and 21). The antibody anti-HBs is reevaluated 4 weeks after the last dose and a fourth dose might be administrated if necessary.
Seroconversion status was defined as the outcome variable. To evaluate if immunosenescence influenced seroconversion, we compared the seroconversion rate of patients 50-years-old or younger and older than 50; to evaluate if DMTs were determinant in seroconversion rates we compared the following groups of patients: treatment-naïve, under BRACE and non-BRACE DMTs.
We included 101 patients, 58 (57.4%) female, mean age 45.7 ± 13.5 years. At the time of vaccination 33 (32.7%) patients were treatment-naïve, while the remaining 68 (67.3%) were under the following DMTs: 27.7% BRACE, 8.9% teriflunomide, 12.9% dimethyl fumarate, 7.9% fingolimod and 9.9% natalizumab.
Seroconversion was observed in 69.3% of patients following vaccination. The seroconversion rate was similar between different age groups: 74.1% vs 69.2% in patients 50-years-old or younger and older than 50, respectively (p=0.65). The seroconversion rates were similar between BRACE-treated and treatment-naïve patients (85.2% vs 81.8%, p=1) but lower in the group of patients under non-BRACE DMTs comparing to BRACE- treated patients (54.1% vs 85.2%, p=0.014) and treatment-naïve patients (54.1% vs 81.8%, p=0.021).
Seroconversion following HBV vaccination was not influenced by age in our sample; however, treatment with DMTs other than BRACE was associated with a lower seroconversion rate following vaccination. Vaccination should then be considered at an early stage of MS treatment, preferably in naïve-RRMS or patients under BRACE DMTs.