To Vaccinate, or Not, in Patients With MS

Q) Are vaccines safe for patients with multiple sclerosis?

Vaccines are an important component of general disease prevention and are especially useful for patients with chronic illnesses, such as MS, who may be at elevated risk due to disability or medications that alter the immune system. Currently, there are many disease-modifying therapies that attempt to reduce relapses and impact the immune system, MRI activity, and disability. But is it safe for patients with MS to receive vaccines, given the multitude of studies suggesting that infections may increase relapse rate?

In 2002, the American Academy of Neurology published a summary of evidence and recommendations to provide guidance for practitioners.¹ The data showed an increased risk for MS relapse during the weeks following infection.^2,3 Therefore, preventing infections is beneficial for patients with MS. An analysis of studies in patients with MS who were vaccinated with inactivated vaccines (influenza, hepatitis B, tetanus) found sufficient evidence to support this practice. Studies of patients with MS who were given attenuated vaccines did not find enough evidence to support or reject these vaccines, except in the case of varicella. A study with sufficient follow-up concluded that varicella vaccination was safe for patients with MS who were not immunosuppressed. As a result of this effort, the MS Council for Clinical Practice Guidelines recommends that patients and health care providers follow the CDC’s indications for immunizations (www.cdc.gov/vaccines/schedules/hcp/adult.html).¹

On the other hand, administration of the live-virus yellow fever vaccine in patients with clinically relapsing MS was correlated with an increased risk for disease progression in one study.⁴ The researchers followed disease progression, measured by relapses and MRI activity, in patients taking glatiramer acetate and interferon ß. Relapse rates reached 8.57 within three months after vaccination, compared to a rate of 0.67 the year prior to vaccine administration. Additionally, significant changes were seen on MRI; new or enlarging T2-weighted lesions and gadolinium-enhancing lesions were observed at three months, compared to 12 months prior and nine months after.⁴ Therefore, the researchers concluded that patients with MS traveling to endemic yellow fever areas should be cautioned regarding the risk for disease progression with vaccination, versus the risk for exposure to yellow fever.

Over the past decade, as newer therapies with different mechanisms of action have become available, concern has risen that patients may not respond to immunizations or may have a higher risk for infection after vaccination. For that reason, several studies have evaluated the ability of patients with MS to mount a normal antibody and cellular immune response after vaccine administration. In 2016, a study by Lin et al determined that patients who received daclizumab were able to mount a normal response after influenza vaccination.⁵