All drugs come with both benefits and risks.
For people with multiple sclerosis (MS) who take anti-CD20 therapies — which include ocrelizumab (Ocrevus), ofatumumab (Kesimpta), rituximab (Rituxan), and ublituximab (Briumvi) — the primary benefit is fewer relapses and less disability progression.
One potential downside is a higher risk of infection, especially over the long term, as noted in this NeurologyLive peer exchange.
Neuroinvasive West Nile Virus
Now a paper published in the journal Neurology finds that people with MS being treated with ocrelizumab could be as much as 258 times more likely than the average population to contract neuroinvasive West Nile virus.
What’s neuroinvasive West Nile virus? It’s West Nile virus — currently the leading cause of mosquito-borne disease in the United States — that infects the nervous system, particularly the central nervous system (brain and spinal cord).
The researchers found only four people, all women, out of a pool of 2,009 people with MS on ocrelizumab, who developed neuroinvasive West Nile virus. But that was compared with the entire populations of Pennsylvania and New Jersey, where only a total of 86 people were diagnosed with neuroinvasive West Nile virus during the study period.
Symptoms of West Nile Virus
These aren’t panic numbers, but if you are using ocrelizumab, it might be worth noting the symptoms of West Nile virus described by the Centers for Disease Control and Prevention (CDC). They include fever, headache, body aches, joint pains, vomiting, diarrhea, and rash, along with fatigue and weakness.
The women in this report additionally had symptoms indicating they had developed meningoencephalitis — a life-threatening condition in which a person has meningitis and encephalitis at the same time.
Meningitis is an infection or inflammation of the area surrounding the brain and spinal cord, according to the Cleveland Clinic, and encephalitis is inflammation of the brain tissue itself. According to the CDC, symptoms of West Nile virus infection of the central nervous system include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis.
Diagnosing West Nile Virus
Normally, healthcare providers diagnose West Nile virus on the basis of symptoms, a history of mosquito bites, and laboratory tests.
However, in the case of the women using ocrelizumab, it appeared that the use of an anti-CD20 therapy reduced the sensitivity of the blood tests doctor used to determine what was causing the women’s symptoms — meaning the test results were negative for West Nile virus when in fact they should have been positive.
The researchers concluded that a West Nile virus diagnosis “requires a high index of suspicion” on the part of medical professionals for people on immunosuppressive therapies who have signs and symptoms like those experienced by the women described in this article.
How Do You Protect Yourself From West Nile Virus Infection?
For most people, the only way to prevent West Nile virus is to take steps to avoid getting bitten by mosquitoes in the first place.
The CDC offers these tips:
- Use insect repellent.
- Wear long-sleeve shirts and long pants.
- Treat your clothes with permethrin.
- Use screens on windows and doors to keep mosquitoes out of your home.
- Empty any water-holding containers — such as buckets or flowerpots — inside or outside your home once a week to stop mosquitoes from laying eggs.
Be careful out there, kids.
Wishing you and your family the best of health.
Cheers,
Trevis
