Ocrevus may remove chicken pox immunity

The multiple sclerosis (MS) drug Ocrevus (ocrelizumab) may interfere with chicken pox immunity acquired from a vaccine, according to a new case study from Italy.

Ocrevus suppresses the immune system’s attacks on the myelin sheath. It targets mature B-cells and has been shown to allow the development of new B-cells and to preserve the immunity a patient has gained from previous infections or vaccinations. But there is some evidence treatment with Ocrevus has caused some people to lose the immunity they have gained from vaccines to prevent influenza or pneumococcal bacteria.

In this latest case study, researchers at the Magna Graecia University of Catanzaro in Italy wrote about the case of a 48 year old man with relapsing remitting MS (RRMS). The man had been vaccinated against the varicella-zoster (chicken pox) virus. He was screened and his immunity against the virus was confirmed.

Four months after he was immunised, he received the first Ocrevus treatment, with a second dose given a fortnight later. The patient was re-screened for anti-varicell-zoster and it was found he no longer had immunity. He was re-vaccinated

After five months, the patient was re-screened. Results showed he no longer had protective levels of anti-varicella-zoster virus antibodies in his blood, and he was given a second vaccine. He was then tested again eight weeks later but had not regained immunity.

The researchers decided not to vaccinate again but recommended a prevention strategy through avoiding coming into contact with anyone who may have the active virus and immunising the patient’s family.

The study’s authors also recommended people with MS taking Ocrevus should be re-tested for immunity against the varicella-zoster virus.