Exchange Transfusion Linked to Better Outcomes in Severe Babesiosis
Study Findings Show Significantly Reduced Risk of Death or Readmission, Offering Clearer Direction for Care
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Babesiosis, a tick-borne disease seen worldwide, has increased sharply in recent years, especially across the northeastern United States. For patients with severe illness, red blood cell exchange transfusion (ET) is commonly used—but evidence of its clinical benefit has been limited. A new study by a national group of researchers, including Marc El Khoury, M.D., associate professor of medicine at New York Medical College, now provides that evidence, reporting a significant benefit in findings published in JAMA Internal Medicine.
“We found that among severely ill adults hospitalized with babesiosis, the adjusted risk of in-hospital death or 30-day readmission was nearly five times lower in those treated with ET versus those who did not receive it,” says Dr. El Khoury. “Because ET is an invasive and resource-intensive intervention, there has been uncertainty about when to use it. Our study helps define which patients stand to benefit most, giving clinicians clearer direction and greater confidence in their decision-making.”
The multicenter cohort study included 629 patients hospitalized with severe babesiosis from 2010 to 2024 at 82 sites across the northeastern United States. Among them, 33 percent received ET within the first seven days of admission. The combined rate of in-hospital death or 30-day readmission was 3.6 percent among patients treated with ET, compared with 9.8 percent among those not treated.
“Another surprising result was that age did not affect the association between ET and outcomes,” says Dr. El Khoury. “This was unexpected given that many prior smaller studies showed increased mortality and comorbidity with patients older than 70.”
Dr. El Khoury also noted that a previous case series with a smaller cohort of patients, published in Pathogens as recently as 2025, did not show the same outcome. “We needed to examine a larger number of cases to improve the power of the study to show significance that was not evident from small individual case series,” he says. “While further trials remain necessary, providers will now have clearer parameters to help them decide when to use ET and who will clearly benefit from it.”
