08/25/2026
The CDC is alerting clinicians that individuals taking anti-CD20 therapies are especially vulnerable to neuroinvasive disease from tick- and mosquito-borne viruses. The CDC said it is issuing the warning now because the US “had an early and strong start to this year’s West Nile virus season and many weeks of the arbovirus transmission season remain.”
Anti-CD20 monoclonal antibodies — which include rituximab and its biosimilars, ocrelizumab, ofatumumab, ublituximab, obinutuzumab, and ibritumomab tiuxetan — have warnings in labeling of the potential for serious infections, including West Nile virus. https://mdsc.pe/4cW4Mty