Up until recently, measles vaccination has been so effective that there’s been little medical or financial incentive to develop treatments for the disease.
But as measles cases hit a 35-year high and vaccination rates continue to decline in the US, a handful of biotech companies and academic groups have started working on measles treatments for those infected with the virus as well as vulnerable individuals needing short-term protection. It will likely be years, however, before these countermeasures are available, and it’s even more uncertain if those who refuse vaccines would take such treatments.
Fueled by large outbreaks in South Carolina and Utah, the US had already surpassed last year’s 2,289 measles cases, and it’s only July. For comparison, there were just 285 cases in all of 2024.
Because measles is so contagious, at least 95 percent of people in a community need to receive both doses of the measles vaccine to protect immunocompromised individuals and infants under 12 months old who are too young to be vaccinated. But measles vaccination rates have dipped well below that in many places across the country.
Young children are the most susceptible to severe complications from measles. The virus can cause pneumonia by damaging the respiratory tract lining directly and by suppressing the immune system, leaving them susceptible to bacterial infections. It can also cause deafness and potentially fatal brain damage. Without a measles-specific treatment, doctors rely on supportive care such as preventing dehydration, managing breathing difficulties, and administering steroids for inflammation. Vitamin A is sometimes given to patients because the virus can deplete levels of it in the body, but the supplement has no effect on the virus itself.
“What we’re seeing now as we get a resurgence of measles in communities is a horrible lack of options when somebody gets exposed,” says Michael Mina, an epidemiologist and chief medical officer of Invivyd, a Connecticut-based biotech company.
Invivyd is developing a type of therapy for measles known as a monoclonal antibody, which mimics natural antibodies the immune system makes to fight off disease. Given via IV or injection, monoclonal antibodies were widely used to treat and prevent Covid-19, especially in immunocompromised individuals who didn’t mount a strong immune response to the vaccines. Their protective effects can last up to a few months.
Invivyd, which developed a monoclonal antibody for Covid, has been getting inquiries from health care providers about when a similar therapy will be available for measles. In the event of a local measles outbreak, a monoclonal antibody could provide short-term protection to those at high risk of contracting the virus. Invivyd has not yet tested its measles antibody in humans, but Mina says the company is compiling the data needed for the Food and Drug Administration to sign off on clinical trials.
At the La Jolla Institute for Immunology, president and CEO Erica Ollmann Saphire has been trying to understand the human antibody response to measles. In May, Saphire and her team published a study describing human antibodies capable of blocking infection by binding to key sites on the measles virus. An infusion of these antibodies resulted in a 500-fold lower viral load in rodents.
A key step toward getting these treatments into human trials will be manufacturing monoclonal antibodies at scale, which is a costly and complex process. Clinical trials cost millions of dollars to run, and pharmaceutical partners are usually needed to fund them. But measles treatments could be a hard sell for pharma companies. Drugs for infectious diseases aren’t usually big money-makers because of the sporadic nature of outbreaks and short treatment courses.
“I think this is a real opportunity to solve a public health problem,” Saphire says. “A tool by which you could prevent or treat disease is still cheaper than managing an outbreak or managing a case of fatal encephalitis in a child.” Some disease models predict that measles could become endemic in the US in the next 25 years, even at current state-level vaccination rates.
Monoclonal antibodies could also be costly for patients and insurers. In early 2022, the US government spent $855 million for 1.7 million doses of Evusheld, a monoclonal antibody treatment authorized for Covid. The medication itself was free to patients, but some people were hit with hundreds of dollars in out-of-pocket costs related to the administration of the drug.
The monoclonal antibody combination that became Evusheld was created in just 25 days by scientists at Vanderbilt University, which have also discovered potent antibodies for measles. The university has partnered with small biotech firm Saravir Biopharma to continue development.
James Crowe, an immunologist and director of the Vanderbilt Center for Antibody Therapeutics who led the Covid work, says the strategy is to use a combination of two monoclonal antibodies to drastically reduce the chances that the measles virus could mutate to evade it. His group has been systematically making human antibodies against viruses that are most likely to cause future pandemics and happened to be in the middle of the measles work last year when US measles cases intensified.
“The antibodies that we have isolated are so potent, they strongly inhibit the virus. We feel for sure they could be formulated as a single, long acting shot,” Crowe says.
Once these monoclonal antibodies are ready for human testing, regulators will need to figure out how to evaluate them in clinical trials. New drugs are typically tested in adults first to make sure they’re safe for children. But complications from measles are more likely to hospitalize children, particularly those who are unvaccinated.
Antivirals could also be used as a strategy to treat measles, although they tend to be short-lived and must often be given very soon after a person is infected or starts to develop symptoms to be effective. Researchers at Georgia State University identified an oral antiviral drug and tested it in rats, ferrets, and dogs infected with related viruses in the orthoparamyxovirus subfamily since these animals don’t get human measles. The drug lowered viral load and all treated animals survived. It’s not yet been tested in people.
A challenge in antiviral development is that drugs toxic enough to kill viruses often have unpleasant side effects for people.
The big question, though, is if people will use the treatments being developed or allow their children to take them. While anti-vaccine sentiment is driving the current outbreaks, Mina of Invivyd hopes people who have not vaccinated their children or gotten the vaccine themselves will be open to getting a monoclonal antibody because “this is a molecule that our bodies create naturally.”
But during the Utah measles outbreak, some parents have refused to let doctors give their children immune globulin, a broad mix of antibodies derived from donated plasma. And anti-science sentiment has become more mainstream with Robert F. Kennedy Jr. leading the Department of Health and Human Services, where he has cast doubt on vaccines, treatments for depression, and other established medical treatments.
That doesn’t mean researching antibodies and other treatments for measles isn’t worth the effort, though, particularly given the potential to help populations who are unable to be vaccinated. Crowe says it’s important that work on measles treatments gets funded as vaccination rates continue to decline.
“I think there’s going to be hundreds of thousands of cases,” he says. “People are going to die. There’s some urgency to finishing this work.”
