Despite near-eradication following the introduction of the measles-mumps-rubella (MMR) vaccine in 1963, lower vaccination rates due to vaccine hesitancy have led to recent measles and mumps outbreaks in the Unites States. Decreased vaccination causes a drop in herd immunity, which protects individual people who are immunosuppressed or have contraindications to vaccination. Specifically, patients with immune cell-related cancers and those who receive hematopoietic stem cell transplants (HCT) or other immunosuppressive treatments are highly susceptible to severe disease and mortality resulting from infection with measles and mumps. Although decreased MMR vaccination in the general population has been documented, little is known about the prevalence of measles and mumps immunity in cancer patients, despite the potential for catastrophic consequences in the event of a measles or mumps outbreak at a cancer treatment center.
In a recent study published in JAMA Network Open, Sara Marquis, along with collaborators from the University of Washington, the Seattle Cancer Care Alliance, and the Fred Hutch Vaccine and Infectious Disease Division, sought to determine the seroprevalence of protective anti-measles or mumps antibodies in people with cancer. “Before our study, these data were largely unavailable for U.S. cancer patients, making it difficult for cancer centers to plan for potential outbreaks,” said Elizabeth Krantz, one of the lead authors of this research. The researchers tested plasma samples for measles or mumps antibodies from nearly 1,000 outpatients who received care from the Seattle Cancer Care Alliance in 2019 to determine what percentage of cancer patients were unprotected. “Our study provided estimates of how many and which types of cancer patients we might expect to be at greatest risk of acquiring measles or mumps in the event of an outbreak in the community,” Krantz explained. “Briefly, one in four cancer patients lacked protective antibodies for measles and more than one in three patients lacked protective antibodies for mumps. These deficits in protective antibodies were most common among younger patients (those aged 30-59 years old), those with hematologic malignancies, and hematopoietic cell transplant recipients,” she continued.
This alarming finding could be the result of several factors. Although some cancer patients may simply not have been vaccinated against measles and mumps, many have medical explanations for a lack of protective antibodies. Blood cancers affect immune cells; therefore patients with hematologic malignancies may have aberrant immune responses that fail to produce protective antibodies in response to vaccination. Likewise, hematopoietic cell transplants patients lose their original antibody-producing B cells and undergo a waiting period before they are eligible for re-vaccination. Complications such as these render the population of people with cancer extremely susceptible to infection and rely on others’ vaccinations to keep them safe. Dr. Steve Pergam, a senior author on this study, expanded on the importance of herd immunity in relation to cancer patients: “Improving community immunity is critical to preventing outbreaks, transmission and infections from vaccine preventable diseases, because cancer patients are better protected when everyone around them is vaccinated. Targeting education about the importance of vaccines to household contacts and family of our cancer patients, we can assure our patients are more insulated from measles.”
Going forward, Dr. Pergam said that these findings “are important to help ‘set the table’ for future outbreaks of measles in our community. We have seen Measles outbreaks in Washington state as recently as 2019, and so we need to be prepared. Data has already shown that childhood vaccination rates have dropped since the start of COVID-19 throughout the world, so we are worried about the potential that Measles outbreaks will follow.” Because some cancer patients cannot rely on their own vaccine-elicited immunity to protect themselves, the safety of the environment where they receive treatment is crucial. “By understanding risk within the center, we can organize our system for the next community outbreak. We also hope that these data help to strengthen policies for mandatory vaccines among healthcare workers to include vaccines beyond just COVID-19. Finally, we want these data to shift how our center approaches vaccines among those around cancer patients,” Dr. Pergam said.
Marquis SR, Logue JK, Chu HY, Loeffelholz T, Quinn ZZ, Liu C, Stewart FM, Carpenter PA, Pergam SA, Krantz EM. Seroprevalence of Measure and Mumps Antibodies Among Individuals With Cancer. JAMA. 2021 Jul 1;4(7):e2118508. doi: 10.1001/jamanetworkopen.2021.18508.
This work was supported by the National Cancer Institute and the Seattle Cancer Care Alliance.
Fred Hutch/UW Cancer Consortium members Paul Carpenter, Catherine Liu, and Steven Pergam contributed to this work.