Beyond Vaccines: The Search for Measles Antiviral Treatments

Measles cases in the United States are rising, with 2,030 cases reported as of June 4, 2025, putting the country at risk of losing its measles elimination status. Because no antiviral treatments currently exist, researchers are developing new drug candidates and monoclonal antibodies to protect unvaccinated and vulnerable populations, according to reports from health experts and virologists.

The current surge follows a trend where 2025 and 2026 case counts have become the largest in more than three decades. More than 90 percent of the 2,030 cases reported by June 4 occurred in people who were unvaccinated or whose status was unknown.

Why are measles cases increasing in the U.S.?

Vaccination rates are slipping across the U.S., Canada, and parts of Europe. This decline is driven by a lack of medical access, distrust of professionals, and concerns about vaccine safety that scientific evidence does not support.

A population needs vaccination rates above 95 percent to create a “blockade of protection,” according to the provided data. This threshold protects those unable to be vaccinated, such as infants under one year old and people with compromised immune systems.

Did You Know? Two doses of the measles vaccine prevent approximately 97 percent of cases.

What are the health risks of a measles infection?

The virus can cause severe complications including pneumonia and blindness, according to structural virologist Kathryn Hastie of the La Jolla Institute for Immunology. Measles can also erase immune memory, making patients more susceptible to other infections.

San Antonio researchers developing first-ever measles treatment

Severe neurological outcomes are also possible. Hastie notes that about 1 out of every 1,000 infected people develop encephalitis, which may lead to permanent brain damage. Additionally, 1 to 3 children die for every 1,000 infected.

How are researchers developing new measles treatments?

Because physicians can currently only manage symptoms like fever and rash, scientists are pursuing two primary paths: antivirals and monoclonal antibodies.

Richard Plemper, a virologist at Georgia State University, developed an antiviral candidate called GHP-88310. In tests involving ferrets infected with canine distemper virus—a proxy for measles—the drug dampened viral replication and all treated animals survived, as reported May 22 in Science Advances.

Separately, Kathryn Hastie and her team are testing monoclonal antibodies, which provide “on-demand immunity.” In a May 7 report in Cell Host and Microbe, the team found that infusing human antibodies into infected cotton rats decreased the virus in the lungs, with one antibody reducing the virus to undetectable levels.

Expert Insight: Samantha Carter notes that while vaccines provide long-term defense, monoclonal antibodies offer an immediate response. The trade-off is cost; antibodies are generally more expensive to produce than antivirals, though they may offer higher specificity and fewer side effects.

What happens next for measles drug development?

Clinical trials for measles treatments face significant hurdles. Richard Plemper notes that unpredictable outbreak locations and the ethical requirement to offer vaccines to children before trial enrollment make recruitment difficult.

As a possible next step, Plemper’s team plans to test GHP-88310 on human parainfluenza virus type 3. Because this virus is in the same family as measles and lacks a vaccine, success in these trials could eventually lead to the drug’s availability for measles outbreaks.

Frequently Asked Questions

Are there any current antiviral drugs for measles?
No. According to Ruth Lynfield of the Minnesota Department of Health, there are currently no antiviral treatments against measles, and developing them has not historically been a priority.

What is the difference between the vaccine and monoclonal antibodies?
Vaccines teach the body to recognize the virus and build defenses over several weeks. Monoclonal antibodies deliver pre-made, “hand-picked” proteins that work immediately to control infection, according to Kathryn Hastie.

Why is the Orthoparamyxovirus subfamily important?
This subfamily includes measles, Nipah virus, and two human parainfluenza viruses. Researchers like Richard Plemper target this group so that one drug, such as GHP-88310, could potentially treat multiple related human pathogens.

Do you believe increased investment in antiviral research is the right backup plan for declining vaccination rates?