Researchers pursue measles antivirals and antibodies as U.S. cases rise

U.S. measles cases reached 2,030 as of June 4, 2026, already surpassing the 2,288 cases recorded for all of 2025. More than 90 percent of this year's cases occurred in unvaccinated individuals or people whose vaccination status is unknown. The increase follows declining vaccination rates in the United States, Canada, and parts of Europe.

Officials have stated the country risks losing its measles elimination status.

Limited treatment options No antiviral drugs specifically approved for measles exist. Physicians currently manage symptoms such as fever, cough, fatigue, and rash but cannot target the virus itself. Ruth Lynfield, an epidemiologist at the Minnesota Department of Health, said during a May 27 news briefing that development of measles antivirals had not been a priority because of the vaccine's effectiveness.

Antiviral research Richard Plemper, a virologist at Georgia State University, led a team that screened more than 100,000 compounds. One candidate, GHP-88310, reduced viral replication and allowed survival in ferrets infected with canine distemper virus, a related pathogen.

The compound binds to a viral protein required for replication across the Orthoparamyxovirus subfamily. Plemper said the drug could eventually serve as a post-exposure treatment or prophylactic for unvaccinated individuals.

Antibody approach Kathryn Hastie, a structural virologist at the La Jolla Institute for Immunology, and colleagues isolated four measles antibodies from a vaccinated person. When infused into infected cotton rats, the antibodies lowered lung viral loads, with one reducing the virus to undetectable levels.

The team reported the findings May 7 in Cell Host and Microbe. Earlier studies of another candidate, mAb 77, also showed reduced viral loads in cotton rats. Vaccination with two doses prevents approximately 97 percent of cases and remains the primary public health tool.