Coping with a shattered immune system: COVID and beyond
Preparing for measles
Measles lit up on Dr. Pergam’s radar screen in 2019, when an outbreak occurred in nearby Clark County, Wash. This and other outbreaks in New York, California, and other states highlighted declines in measles herd immunity in the United States and prompted him to investigate the seroprevalence of measles antibodies in the Fred Hutchinson Cancer Research Center’s outpatient population.
Of 959 consecutive patients seen at the center, they found, 25% lacked protective antibodies for measles. For patients with hematologic malignancies and those with a history of HCT, seroprevalence was worse: 37% and 54%, respectively, were without the IgG antibodies.4 Measles “is the most contagious human virus we have at the moment,” he said, and “revaccinating people is hard when it comes to cancer because it is a live virus vaccine.”
Vaccine hesitancy, a rise in nonmedical exemptions, and other factors were threatening herd immunity before the pandemic began. Now, with declines in routine childhood medical visits and other vaccination opportunities and resources here and in other countries – and declining immunization rates documented by the CDC in May 2021 – the pandemic has made measles outbreaks more likely, he said. (Measles outbreaks in West Africa on the tail end of the Ebola outbreak in 2014-2015 caused more deaths in children than Ebola, he noted.)
The first priority is vaccination “cocooning,” a strategy that has long been important for patients with hematologic malignancies. But it also possible, Dr. Pergam said, that in the setting of any future community transmission, revaccination for HCT recipients could occur earlier than the standard 2-year post-transplantation recommendation.
In a 2019 position statement endorsed by the American Society for Transplantation and Cellular Therapy, Dr. Pergam and other infectious disease physicians and oncologists provide criteria for considering early revaccination on a case-by-case basis for patients on minimal immunosuppressive therapy who are at least 1-year post transplantation.5
“Our thinking was that there may be lower-risk patients to whom we could offer the vaccine” – patients for whom the risk of developing measles might outweigh the risk of potential vaccine-related complications, he said.
And if there were community cases, he added, there might be a place for testing antibody levels in post-transplant patients, however imperfect the window to immunity may be. “We’re thinking through potential scenarios,” he said. “Oncologists should think about measles again and have it on their back burner.”
References
1. Grivas P et al. Ann Oncol. 2021 Jun;32(6):787-800.
2. Agha ME et al. Open Forum Infect Dis. 2021 July;8(7):ofab353.
3. Greenberger LM et al. Cancer Cell. 2021 Aug 9;39(8):1031-3.
4. Marquis SR et al. JAMA Netw Open. 2021 July;4(7):e2118508.
5. Pergam SA et al. Biol Blood Marrow Transplant. 2019 Nov;25:e321-30.
