As Measles Cases Reach a Record High, Oncologists Feel the Impact

Despite the elimination of measles in the US in the 2000s due to effective vaccination,¹ measles cases are the highest in 33 years, with more than 1,000 cases reported in 2025 as of July.²

“This outbreak has brought an acute awareness of the vulnerability of cancer patients to vaccine-preventable diseases, like measles, as well as highlighting how important community herd immunity is for protecting our most vulnerable patients,” said Amy Spallone, MD, chief infection control officer at The University of Texas MD Anderson Cancer Center.

The highly contagious disease, which can be difficult to spot, can have profound impacts on oncology patients and lead to major complications.

A Vulnerable Population

A quarter of ambulatory patients with cancer lacked the antibodies needed to protect themselves against measles, and 38% lacked the antibodies needed for protection against mumps, according to a 2021 study published in JAMA Network Open. Research suggests that while rare, measles outbreaks in oncology wards can have a fatality rate of 70%.³

The cross-sectional study looked at outpatients who received care at the Fred Hutchinson Cancer Research Center’s Seattle Cancer Care Alliance. All 959 patients included in the study had residual plasma samples available after routine clinical testing over a 5-day period in August 2019.³

Most patients (75%) had a positive measles antibody test, 17% had a negative test, and 8% had equivocal results. Immunity deficiencies were the most common in patients between the ages of 30 and 59 with hematologic malignant neoplasms who underwent hematopoietic stem cell transplant (HSCT).³

Other studies suggest that children are at a particular risk. Case fatalities for childhood leukemia patients can range from 13% to 83%, according to a position statement published in Transplantation and Cellular Therapy.⁴

“Those who become infected while undergoing active cancer treatment or with hematologic malignancies are more susceptible to contracting measles and experiencing complications, like pneumonia, encephalitis, and other severe respiratory or neurological issues,” said Dr. Spallone.

Additionally, immunosuppressed patients are more likely to experience complications related to the disease. It is estimated that approximately half of patients with hematological malignancies and a measles infection develop life-threatening complications, including pneumonia, liver failure, and encephalitis.⁴

However, protecting this population isn’t as easy as administering a vaccine.

“Given that any immunity that you might have previously had is lost with an autologous transplant, you need to revaccinate after the transplant. With an allogeneic transplant, where you have to consistently suppress the immune system to prevent the graft from attacking the body, an infection such as measles could lead to unnecessary fatalities,” said Tycel Phillips, MD, associate professor of medicine at the City of Hope National Medical Center.

The current measles, mumps, and rubella (MMR) vaccine uses a live attenuated strain—the Edmonston-Enders strain—and results in greater than 93% protective immunity in normal hosts. In 1989, it was recommended that two doses of the vaccine be administered to immunocompromised children. A third dose did not improve immune responses.⁴

For patients receiving exogenous immunosuppression, it isn’t as simple. When it comes to vaccine administration, timing is vital. For patients with leukemia, the MMR vaccine should be administered at least 3 months after the conclusion of chemotherapy and 6 months after the administration of anti–B-cell antibodies, such as rituximab. Patients who have received autologous or allogeneic HSCT and are off immunosuppression and not receiving certain relapse prophylaxis or maintenance therapies can receive the vaccine 24 months post-transplantation.⁴

For patients who are more than 24 months post-allogeneic HSCT but require prolonged immunosuppressive therapy for chronic graft-versus-host disease, the vaccine can only be administered 8 to 11 months after ending immunosuppression therapy. The vaccine is not recommended for those receiving rituximab maintenance, but may be safe for those receiving bortezomib or lenalidomide.⁴

However, these guidelines were designed for situations in which there is no increased risk from community clusters or disease outbreaks. During large outbreaks, the benefits of vaccination may outweigh the associated risks. However, oncologists should take a case-by-case approach when deciding if vaccination is necessary and only after patients are at least 1 year post-transplantation.⁴

“For oncologists and healthcare providers, it is essential to discuss vaccinations with our patients, including revaccination during community outbreaks for those who are eligible to receive the vaccine. Immunocompromised patients who cannot receive the vaccine should avoid travel to areas known to have active measles cases,” said Dr. Spallone.

Steps for Oncologists

Many US healthcare professionals have seen few—if any—measles cases during their practice, making it difficult to determine an appropriate response.⁴ The evasive nature of the virus, which has an incubation period of 10 to 14 days, further complicates this. The period of contagiousness can be difficult to pin down, as RNA can appear for months after the appearance of the rash associated with the disease.⁵ Additionally, before the appearance of the rash, measles symptoms are similar to those of most common respiratory viruses. This can make pinning down exposure in a timely manner incredibly difficult.⁵

“The measles virus can live for up to 2 hours in an airspace in which an infected person has coughed or sneezed. Therefore, when considering exposures, those who were in the same space (eg, playroom, household, clinic, waiting room) as the contagious patient for up to 2 hours, after that patient was present should be considered at risk for measles exposure,” said Heather Symons, MD, MHS, clinical director of pediatric blood and marrow transplantation at Johns Hopkins Medicine.

In areas with active exposures, extra steps should be taken before the patient enters the facility. Those who screen positive should be isolated and undergo further testing. Additionally, transplant recipients should be fully educated on the impact of exposure and told to report any possible contact, along with limiting exposure to caregivers and family.⁴

If a patient tests positive or presents with concerning symptoms, they should be brought to a negative-pressure isolation room with airborne precautions. Portable rooms can be used if available. After the patient leaves the room, it should be left unoccupied for 2 hours then terminally disinfected. If negative-pressure rooms are not available, the patient should be put in a room by themselves with the door closed. All staff should use an N-95 mask or powered air purifying respirator along with standard measures.⁴

“The best measures to prevent an outbreak among our patients are to prevent possible measles-infected individuals from having contact with other patients on campus,” said Dr. Spallone. “Specifically, we aim to quickly identify possible measles cases, place those patients on appropriate isolation precautions, and then alert hospital Infection Control so that additional investigations can begin in partnership with local public health authorities.”

During times of widespread outbreak, cancer centers may need to take additional precautions, such as targeted screenings. After exposure, airborne isolation precautions should be maintained for 21 days, and 28 days for patients who receive postexposure prophylaxis with intravenous immunoglobulin.⁴

However, precautions can lead to care delays or interruptions, especially if isolation is needed. Additionally, outbreaks can have a financial impact on affected hospitals.

“In areas with outbreaks, or ongoing measles transmission, special screening and precaution measures that take time, money, and resources have had to be implemented. Some hospitals have needed to implement stricter isolation protocols, including designated areas for measles patients, enhanced hygiene practices, and increased surveillance for potential outbreaks,” said Dr. Symons. “Exposure to measles can lead to delays or changes in cancer treatment plans, as patients may need to be isolated or their treatment schedule adjusted.”