Transfusion-Transmitted Yellow Fever Vaccine Virus Linked to Neurological Disease in Organ Recipients

Transfusion transmission of yellow fever vaccine virus to a solid organ donor appears to be the source of four subsequent cases of neurological disease in patients who received organ transplants from a common donor, according to an investigation published in The Lancet Microbe. Two of the four patients died due to severe neurological disease.

All currently available yellow fever vaccines are live, attenuated vaccines that use the 17D viral substrains. Due to an increased risk of vaccine-associated adverse events, the yellow fever vaccine – like all live vaccines – is contraindicated for immunocompromised individuals, including recipients of solid organ transplants.

In this case, the organ donor had no history of travel in the several months before transplantation or of yellow fever vaccination. To determine the source of the infections, a team led by the Centers for Disease Control and Prevention tested various specimens (blood, cerebrospinal fluid, intraocular fluid, serum and tissues) from the organ donor and recipients.

The investigation confirmed recent infection with yellow fever virus in all four organ recipients by identifying yellow fever virus RNA consistent with the 17D vaccine strain in brain tissue from one recipient and seroconversion after transplantation in three recipients.

The investigators also conducted a traceback of blood transfusions received by the organ donor. During the donor’s nine-day treatment in hospital before organ donation, he received six blood products— five packed red blood cell units and one unit of platelets — from six donors.

The traceback identified that three days before procurement, the organ donor received a blood transfusion from a donor who had received a yellow fever vaccine six days before blood donation. The blood donor did not report receiving any live vaccines within eight weeks of donation during the pre-donation screening. AABB Standards for Blood Banks and Transfusion Services, 33rd edition, recommend a two-week deferral for donor receipt of a live, attenuated yellow fever vaccine.

According to investigators, the report represents the first known transmission of live, attenuated yellow fever vaccine virus through solid organ transplantation to four organ recipients, causing severe neurological disease and two deaths. Furthermore, the authors noted that the investigation highlights the risk of transmission of live vaccine virus strains through blood transfusions.

“This investigation illustrates the importance of the continued adoption and implementation of new safety interventions to reduce the risk of transfusion-transmitted infections,” the researchers wrote. “Health care workers providing yellow fever vaccination should inform patients of the need to defer blood donation for at least two weeks after vaccination.”

Additional information about yellow fever vaccine and blood products is available in Yellow Fever Virus and Yellow Fever Vaccine Fact Sheet.

AABB reminds members of the blood community and public that the FDA-approved vaccines for COVID-19 (both mRNA vaccines and viral vector vaccines) do not contain live virus nor do they cause viral shedding. Furthermore, COVID-19 vaccines are not transmissible by blood transfusion and present no known risk to the safety of the blood supply.